AttributeError check on config no longer works

use new `'Class.trait' in config` check

IPython/core/application.py

@@ -1,373 +1,371
 # encoding: utf-8
 """
 An application for IPython.
 
 All top-level applications should use the classes in this module for
 handling configuration and creating componenets.
 
 The job of an :class:`Application` is to create the master configuration
 object and then create the configurable objects, passing the config to them.
 
 Authors:
 
 * Brian Granger
 * Fernando Perez
 * Min RK
 
 """
 
 #-----------------------------------------------------------------------------
 #  Copyright (C) 2008-2011  The IPython Development Team
 #
 #  Distributed under the terms of the BSD License.  The full license is in
 #  the file COPYING, distributed as part of this software.
 #-----------------------------------------------------------------------------
 
 #-----------------------------------------------------------------------------
 # Imports
 #-----------------------------------------------------------------------------
 
 import atexit
 import glob
 import logging
 import os
 import shutil
 import sys
 
 from IPython.config.application import Application, catch_config_error
 from IPython.config.loader import ConfigFileNotFound
 from IPython.core import release, crashhandler
 from IPython.core.profiledir import ProfileDir, ProfileDirError
 from IPython.utils.path import get_ipython_dir, get_ipython_package_dir
 from IPython.utils.traitlets import List, Unicode, Type, Bool, Dict, Set, Instance
 
 #-----------------------------------------------------------------------------
 # Classes and functions
 #-----------------------------------------------------------------------------
 
 
 #-----------------------------------------------------------------------------
 # Base Application Class
 #-----------------------------------------------------------------------------
 
 # aliases and flags
 
 base_aliases = {
     'profile-dir' : 'ProfileDir.location',
     'profile' : 'BaseIPythonApplication.profile',
     'ipython-dir' : 'BaseIPythonApplication.ipython_dir',
     'log-level' : 'Application.log_level',
     'config' : 'BaseIPythonApplication.extra_config_file',
 }
 
 base_flags = dict(
     debug = ({'Application' : {'log_level' : logging.DEBUG}},
             "set log level to logging.DEBUG (maximize logging output)"),
     quiet = ({'Application' : {'log_level' : logging.CRITICAL}},
             "set log level to logging.CRITICAL (minimize logging output)"),
     init = ({'BaseIPythonApplication' : {
                     'copy_config_files' : True,
                     'auto_create' : True}
             }, """Initialize profile with default config files.  This is equivalent
             to running `ipython profile create <profile>` prior to startup.
             """)
 )
 
 
 class BaseIPythonApplication(Application):
 
     name = Unicode(u'ipython')
     description = Unicode(u'IPython: an enhanced interactive Python shell.')
     version = Unicode(release.version)
 
     aliases = Dict(base_aliases)
     flags = Dict(base_flags)
     classes = List([ProfileDir])
 
     # Track whether the config_file has changed,
     # because some logic happens only if we aren't using the default.
     config_file_specified = Set()
 
     config_file_name = Unicode()
     def _config_file_name_default(self):
         return self.name.replace('-','_') + u'_config.py'
     def _config_file_name_changed(self, name, old, new):
         if new != old:
             self.config_file_specified.add(new)
 
     # The directory that contains IPython's builtin profiles.
     builtin_profile_dir = Unicode(
         os.path.join(get_ipython_package_dir(), u'config', u'profile', u'default')
     )
 
     config_file_paths = List(Unicode)
     def _config_file_paths_default(self):
         return [os.getcwdu()]
 
     extra_config_file = Unicode(config=True,
     help="""Path to an extra config file to load.
     
     If specified, load this config file in addition to any other IPython config.
     """)
     def _extra_config_file_changed(self, name, old, new):
         try:
             self.config_files.remove(old)
         except ValueError:
             pass
         self.config_file_specified.add(new)
         self.config_files.append(new)
 
     profile = Unicode(u'default', config=True,
         help="""The IPython profile to use."""
     )
 
     def _profile_changed(self, name, old, new):
         self.builtin_profile_dir = os.path.join(
                 get_ipython_package_dir(), u'config', u'profile', new
         )
 
     ipython_dir = Unicode(get_ipython_dir(), config=True,
         help="""
         The name of the IPython directory. This directory is used for logging
         configuration (through profiles), history storage, etc. The default
         is usually $HOME/.ipython. This options can also be specified through
         the environment variable IPYTHONDIR.
         """
     )
     _in_init_profile_dir = False
     profile_dir = Instance(ProfileDir)
     def _profile_dir_default(self):
         # avoid recursion
         if self._in_init_profile_dir:
             return
         # profile_dir requested early, force initialization
         self.init_profile_dir()
         return self.profile_dir
 
     overwrite = Bool(False, config=True,
         help="""Whether to overwrite existing config files when copying""")
     auto_create = Bool(False, config=True,
         help="""Whether to create profile dir if it doesn't exist""")
 
     config_files = List(Unicode)
     def _config_files_default(self):
         return [self.config_file_name]
 
     copy_config_files = Bool(False, config=True,
         help="""Whether to install the default config files into the profile dir.
         If a new profile is being created, and IPython contains config files for that
         profile, then they will be staged into the new directory.  Otherwise,
         default config files will be automatically generated.
         """)
     
     verbose_crash = Bool(False, config=True,
         help="""Create a massive crash report when IPython encounters what may be an
         internal error.  The default is to append a short message to the
         usual traceback""")
 
     # The class to use as the crash handler.
     crash_handler_class = Type(crashhandler.CrashHandler)
 
     @catch_config_error
     def __init__(self, **kwargs):
         super(BaseIPythonApplication, self).__init__(**kwargs)
         # ensure current working directory exists
         try:
             directory = os.getcwdu()
         except:
             # raise exception
             self.log.error("Current working directory doesn't exist.")
             raise
 
         # ensure even default IPYTHONDIR exists
         if not os.path.exists(self.ipython_dir):
             self._ipython_dir_changed('ipython_dir', self.ipython_dir, self.ipython_dir)
 
     #-------------------------------------------------------------------------
     # Various stages of Application creation
     #-------------------------------------------------------------------------
 
     def init_crash_handler(self):
         """Create a crash handler, typically setting sys.excepthook to it."""
         self.crash_handler = self.crash_handler_class(self)
         sys.excepthook = self.excepthook
         def unset_crashhandler():
             sys.excepthook = sys.__excepthook__
         atexit.register(unset_crashhandler)
     
     def excepthook(self, etype, evalue, tb):
         """this is sys.excepthook after init_crashhandler
         
         set self.verbose_crash=True to use our full crashhandler, instead of
         a regular traceback with a short message (crash_handler_lite)
         """
         
         if self.verbose_crash:
             return self.crash_handler(etype, evalue, tb)
         else:
             return crashhandler.crash_handler_lite(etype, evalue, tb)
     
     def _ipython_dir_changed(self, name, old, new):
         if old in sys.path:
             sys.path.remove(old)
         sys.path.append(os.path.abspath(new))
         if not os.path.isdir(new):
             os.makedirs(new, mode=0o777)
         readme = os.path.join(new, 'README')
         if not os.path.exists(readme):
             path = os.path.join(get_ipython_package_dir(), u'config', u'profile')
             shutil.copy(os.path.join(path, 'README'), readme)
         self.log.debug("IPYTHONDIR set to: %s" % new)
 
     def load_config_file(self, suppress_errors=True):
         """Load the config file.
 
         By default, errors in loading config are handled, and a warning
         printed on screen. For testing, the suppress_errors option is set
         to False, so errors will make tests fail.
         """
         self.log.debug("Searching path %s for config files", self.config_file_paths)
         base_config = 'ipython_config.py'
         self.log.debug("Attempting to load config file: %s" %
                        base_config)
         try:
             Application.load_config_file(
                 self,
                 base_config,
                 path=self.config_file_paths
             )
         except ConfigFileNotFound:
             # ignore errors loading parent
             self.log.debug("Config file %s not found", base_config)
             pass
         
         for config_file_name in self.config_files:
             if not config_file_name or config_file_name == base_config:
                 continue
             self.log.debug("Attempting to load config file: %s" %
                            self.config_file_name)
             try:
                 Application.load_config_file(
                     self,
                     config_file_name,
                     path=self.config_file_paths
                 )
             except ConfigFileNotFound:
                 # Only warn if the default config file was NOT being used.
                 if config_file_name in self.config_file_specified:
                     msg = self.log.warn
                 else:
                     msg = self.log.debug
                 msg("Config file not found, skipping: %s", config_file_name)
             except:
                 # For testing purposes.
                 if not suppress_errors:
                     raise
                 self.log.warn("Error loading config file: %s" %
                               self.config_file_name, exc_info=True)
 
     def init_profile_dir(self):
         """initialize the profile dir"""
         self._in_init_profile_dir = True
         if self.profile_dir is not None:
             # already ran
             return
-        try:
-            # location explicitly specified:
-            location = self.config.ProfileDir.location
-        except AttributeError:
+        if 'ProfileDir.location' not in self.config:
             # location not specified, find by profile name
             try:
                 p = ProfileDir.find_profile_dir_by_name(self.ipython_dir, self.profile, self.config)
             except ProfileDirError:
                 # not found, maybe create it (always create default profile)
                 if self.auto_create or self.profile == 'default':
                     try:
                         p = ProfileDir.create_profile_dir_by_name(self.ipython_dir, self.profile, self.config)
                     except ProfileDirError:
                         self.log.fatal("Could not create profile: %r"%self.profile)
                         self.exit(1)
                     else:
                         self.log.info("Created profile dir: %r"%p.location)
                 else:
                     self.log.fatal("Profile %r not found."%self.profile)
                     self.exit(1)
             else:
                 self.log.info("Using existing profile dir: %r"%p.location)
         else:
+            location = self.config.ProfileDir.location
             # location is fully specified
             try:
                 p = ProfileDir.find_profile_dir(location, self.config)
             except ProfileDirError:
                 # not found, maybe create it
                 if self.auto_create:
                     try:
                         p = ProfileDir.create_profile_dir(location, self.config)
                     except ProfileDirError:
                         self.log.fatal("Could not create profile directory: %r"%location)
                         self.exit(1)
                     else:
                         self.log.info("Creating new profile dir: %r"%location)
                 else:
                     self.log.fatal("Profile directory %r not found."%location)
                     self.exit(1)
             else:
                 self.log.info("Using existing profile dir: %r"%location)
 
         self.profile_dir = p
         self.config_file_paths.append(p.location)
         self._in_init_profile_dir = False
 
     def init_config_files(self):
         """[optionally] copy default config files into profile dir."""
         # copy config files
         path = self.builtin_profile_dir
         if self.copy_config_files:
             src = self.profile
 
             cfg = self.config_file_name
             if path and os.path.exists(os.path.join(path, cfg)):
                 self.log.warn("Staging %r from %s into %r [overwrite=%s]"%(
                         cfg, src, self.profile_dir.location, self.overwrite)
                 )
                 self.profile_dir.copy_config_file(cfg, path=path, overwrite=self.overwrite)
             else:
                 self.stage_default_config_file()
         else:
             # Still stage *bundled* config files, but not generated ones
             # This is necessary for `ipython profile=sympy` to load the profile
             # on the first go
             files = glob.glob(os.path.join(path, '*.py'))
             for fullpath in files:
                 cfg = os.path.basename(fullpath)
                 if self.profile_dir.copy_config_file(cfg, path=path, overwrite=False):
                     # file was copied
                     self.log.warn("Staging bundled %s from %s into %r"%(
                             cfg, self.profile, self.profile_dir.location)
                     )
 
 
     def stage_default_config_file(self):
         """auto generate default config file, and stage it into the profile."""
         s = self.generate_config_file()
         fname = os.path.join(self.profile_dir.location, self.config_file_name)
         if self.overwrite or not os.path.exists(fname):
             self.log.warn("Generating default config file: %r"%(fname))
             with open(fname, 'w') as f:
                 f.write(s)
 
     @catch_config_error
     def initialize(self, argv=None):
         # don't hook up crash handler before parsing command-line
         self.parse_command_line(argv)
         self.init_crash_handler()
         if self.subapp is not None:
             # stop here if subapp is taking over
             return
         cl_config = self.config
         self.init_profile_dir()
         self.init_config_files()
         self.load_config_file()
         # enforce cl-opts override configfile opts:
         self.update_config(cl_config)
 

IPython/parallel/apps/ipcontrollerapp.py

@@ -1,547 +1,547
 #!/usr/bin/env python
 # encoding: utf-8
 """
 The IPython controller application.
 
 Authors:
 
 * Brian Granger
 * MinRK
 
 """
 
 #-----------------------------------------------------------------------------
 #  Copyright (C) 2008  The IPython Development Team
 #
 #  Distributed under the terms of the BSD License.  The full license is in
 #  the file COPYING, distributed as part of this software.
 #-----------------------------------------------------------------------------
 
 #-----------------------------------------------------------------------------
 # Imports
 #-----------------------------------------------------------------------------
 
 from __future__ import with_statement
 
 import json
 import os
 import stat
 import sys
 
 from multiprocessing import Process
 from signal import signal, SIGINT, SIGABRT, SIGTERM
 
 import zmq
 from zmq.devices import ProcessMonitoredQueue
 from zmq.log.handlers import PUBHandler
 
 from IPython.core.profiledir import ProfileDir
 
 from IPython.parallel.apps.baseapp import (
     BaseParallelApplication,
     base_aliases,
     base_flags,
     catch_config_error,
 )
 from IPython.utils.importstring import import_item
 from IPython.utils.localinterfaces import localhost, public_ips
 from IPython.utils.traitlets import Instance, Unicode, Bool, List, Dict, TraitError
 
 from IPython.kernel.zmq.session import (
     Session, session_aliases, session_flags, default_secure
 )
 
 from IPython.parallel.controller.heartmonitor import HeartMonitor
 from IPython.parallel.controller.hub import HubFactory
 from IPython.parallel.controller.scheduler import TaskScheduler,launch_scheduler
 from IPython.parallel.controller.dictdb import DictDB
 
 from IPython.parallel.util import split_url, disambiguate_url, set_hwm
 
 # conditional import of SQLiteDB / MongoDB backend class
 real_dbs = []
 
 try:
     from IPython.parallel.controller.sqlitedb import SQLiteDB
 except ImportError:
     pass
 else:
     real_dbs.append(SQLiteDB)
 
 try:
     from IPython.parallel.controller.mongodb import MongoDB
 except ImportError:
     pass
 else:
     real_dbs.append(MongoDB)
 
 
 
 #-----------------------------------------------------------------------------
 # Module level variables
 #-----------------------------------------------------------------------------
 
 
 _description = """Start the IPython controller for parallel computing.
 
 The IPython controller provides a gateway between the IPython engines and
 clients. The controller needs to be started before the engines and can be
 configured using command line options or using a cluster directory. Cluster
 directories contain config, log and security files and are usually located in
 your ipython directory and named as "profile_name". See the `profile`
 and `profile-dir` options for details.
 """
 
 _examples = """
 ipcontroller --ip=192.168.0.1 --port=1000  # listen on ip, port for engines
 ipcontroller --scheme=pure  # use the pure zeromq scheduler
 """
 
 
 #-----------------------------------------------------------------------------
 # The main application
 #-----------------------------------------------------------------------------
 flags = {}
 flags.update(base_flags)
 flags.update({
     'usethreads' : ( {'IPControllerApp' : {'use_threads' : True}},
                     'Use threads instead of processes for the schedulers'),
     'sqlitedb' : ({'HubFactory' : {'db_class' : 'IPython.parallel.controller.sqlitedb.SQLiteDB'}},
                     'use the SQLiteDB backend'),
     'mongodb' : ({'HubFactory' : {'db_class' : 'IPython.parallel.controller.mongodb.MongoDB'}},
                     'use the MongoDB backend'),
     'dictdb' : ({'HubFactory' : {'db_class' : 'IPython.parallel.controller.dictdb.DictDB'}},
                     'use the in-memory DictDB backend'),
     'nodb' : ({'HubFactory' : {'db_class' : 'IPython.parallel.controller.dictdb.NoDB'}},
                     """use dummy DB backend, which doesn't store any information.
                     
                     This is the default as of IPython 0.13.
                     
                     To enable delayed or repeated retrieval of results from the Hub,
                     select one of the true db backends.
                     """),
     'reuse' : ({'IPControllerApp' : {'reuse_files' : True}},
                     'reuse existing json connection files'),
     'restore' : ({'IPControllerApp' : {'restore_engines' : True, 'reuse_files' : True}},
                     'Attempt to restore engines from a JSON file.  '
                     'For use when resuming a crashed controller'),
 })
 
 flags.update(session_flags)
 
 aliases = dict(
     ssh = 'IPControllerApp.ssh_server',
     enginessh = 'IPControllerApp.engine_ssh_server',
     location = 'IPControllerApp.location',
 
     url = 'HubFactory.url',
     ip = 'HubFactory.ip',
     transport = 'HubFactory.transport',
     port = 'HubFactory.regport',
 
     ping = 'HeartMonitor.period',
 
     scheme = 'TaskScheduler.scheme_name',
     hwm = 'TaskScheduler.hwm',
 )
 aliases.update(base_aliases)
 aliases.update(session_aliases)
 
 class IPControllerApp(BaseParallelApplication):
 
     name = u'ipcontroller'
     description = _description
     examples = _examples
     classes = [ProfileDir, Session, HubFactory, TaskScheduler, HeartMonitor, DictDB] + real_dbs
     
     # change default to True
     auto_create = Bool(True, config=True,
         help="""Whether to create profile dir if it doesn't exist.""")
     
     reuse_files = Bool(False, config=True,
         help="""Whether to reuse existing json connection files.
         If False, connection files will be removed on a clean exit.
         """
     )
     restore_engines = Bool(False, config=True,
         help="""Reload engine state from JSON file
         """
     )
     ssh_server = Unicode(u'', config=True,
         help="""ssh url for clients to use when connecting to the Controller
         processes. It should be of the form: [user@]server[:port]. The
         Controller's listening addresses must be accessible from the ssh server""",
     )
     engine_ssh_server = Unicode(u'', config=True,
         help="""ssh url for engines to use when connecting to the Controller
         processes. It should be of the form: [user@]server[:port]. The
         Controller's listening addresses must be accessible from the ssh server""",
     )
     location = Unicode(u'', config=True,
         help="""The external IP or domain name of the Controller, used for disambiguating
         engine and client connections.""",
     )
     import_statements = List([], config=True,
         help="import statements to be run at startup.  Necessary in some environments"
     )
 
     use_threads = Bool(False, config=True,
         help='Use threads instead of processes for the schedulers',
     )
 
     engine_json_file = Unicode('ipcontroller-engine.json', config=True,
         help="JSON filename where engine connection info will be stored.")
     client_json_file = Unicode('ipcontroller-client.json', config=True,
         help="JSON filename where client connection info will be stored.")
     
     def _cluster_id_changed(self, name, old, new):
         super(IPControllerApp, self)._cluster_id_changed(name, old, new)
         self.engine_json_file = "%s-engine.json" % self.name
         self.client_json_file = "%s-client.json" % self.name
 
 
     # internal
     children = List()
     mq_class = Unicode('zmq.devices.ProcessMonitoredQueue')
 
     def _use_threads_changed(self, name, old, new):
         self.mq_class = 'zmq.devices.%sMonitoredQueue'%('Thread' if new else 'Process')
     
     write_connection_files = Bool(True,
         help="""Whether to write connection files to disk.
         True in all cases other than runs with `reuse_files=True` *after the first*
         """
     )
 
     aliases = Dict(aliases)
     flags = Dict(flags)
     
 
     def save_connection_dict(self, fname, cdict):
         """save a connection dict to json file."""
         c = self.config
         url = cdict['registration']
         location = cdict['location']
         
         if not location:
             if public_ips():
                 location = public_ips()[-1]
             else:
                 self.log.warn("Could not identify this machine's IP, assuming %s."
                 " You may need to specify '--location=<external_ip_address>' to help"
                 " IPython decide when to connect via loopback." % localhost() )
                 location = localhost()
             cdict['location'] = location
         fname = os.path.join(self.profile_dir.security_dir, fname)
         self.log.info("writing connection info to %s", fname)
         with open(fname, 'w') as f:
             f.write(json.dumps(cdict, indent=2))
         os.chmod(fname, stat.S_IRUSR|stat.S_IWUSR)
     
     def load_config_from_json(self):
         """load config from existing json connector files."""
         c = self.config
         self.log.debug("loading config from JSON")
         
         # load engine config
         
         fname = os.path.join(self.profile_dir.security_dir, self.engine_json_file)
         self.log.info("loading connection info from %s", fname)
         with open(fname) as f:
             ecfg = json.loads(f.read())
         
         # json gives unicode, Session.key wants bytes
         c.Session.key = ecfg['key'].encode('ascii')
         
         xport,ip = ecfg['interface'].split('://')
         
         c.HubFactory.engine_ip = ip
         c.HubFactory.engine_transport = xport
         
         self.location = ecfg['location']
         if not self.engine_ssh_server:
             self.engine_ssh_server = ecfg['ssh']
         
         # load client config
         
         fname = os.path.join(self.profile_dir.security_dir, self.client_json_file)
         self.log.info("loading connection info from %s", fname)
         with open(fname) as f:
             ccfg = json.loads(f.read())
         
         for key in ('key', 'registration', 'pack', 'unpack', 'signature_scheme'):
             assert ccfg[key] == ecfg[key], "mismatch between engine and client info: %r" % key
         
         xport,addr = ccfg['interface'].split('://')
         
         c.HubFactory.client_transport = xport
         c.HubFactory.client_ip = ip
         if not self.ssh_server:
             self.ssh_server = ccfg['ssh']
         
         # load port config:
         c.HubFactory.regport = ecfg['registration']
         c.HubFactory.hb = (ecfg['hb_ping'], ecfg['hb_pong'])
         c.HubFactory.control = (ccfg['control'], ecfg['control'])
         c.HubFactory.mux = (ccfg['mux'], ecfg['mux'])
         c.HubFactory.task = (ccfg['task'], ecfg['task'])
         c.HubFactory.iopub = (ccfg['iopub'], ecfg['iopub'])
         c.HubFactory.notifier_port = ccfg['notification']
     
     def cleanup_connection_files(self):
         if self.reuse_files:
             self.log.debug("leaving JSON connection files for reuse")
             return
         self.log.debug("cleaning up JSON connection files")
         for f in (self.client_json_file, self.engine_json_file):
             f = os.path.join(self.profile_dir.security_dir, f)
             try:
                 os.remove(f)
             except Exception as e:
                 self.log.error("Failed to cleanup connection file: %s", e)
             else:
                 self.log.debug(u"removed %s", f)
     
     def load_secondary_config(self):
         """secondary config, loading from JSON and setting defaults"""
         if self.reuse_files:
             try:
                 self.load_config_from_json()
             except (AssertionError,IOError) as e:
                 self.log.error("Could not load config from JSON: %s" % e)
             else:
                 # successfully loaded config from JSON, and reuse=True
                 # no need to wite back the same file
                 self.write_connection_files = False
                 
         # switch Session.key default to secure
         default_secure(self.config)
         self.log.debug("Config changed")
         self.log.debug(repr(self.config))
         
     def init_hub(self):
         c = self.config
         
         self.do_import_statements()
         
         try:
             self.factory = HubFactory(config=c, log=self.log)
             # self.start_logging()
             self.factory.init_hub()
         except TraitError:
             raise
         except Exception:
             self.log.error("Couldn't construct the Controller", exc_info=True)
             self.exit(1)
         
         if self.write_connection_files:
             # save to new json config files
             f = self.factory
             base = {
                 'key'  : f.session.key.decode('ascii'),
                 'location'  : self.location,
                 'pack'      : f.session.packer,
                 'unpack'    : f.session.unpacker,
                 'signature_scheme' : f.session.signature_scheme,
             }
             
             cdict = {'ssh' : self.ssh_server}
             cdict.update(f.client_info)
             cdict.update(base)
             self.save_connection_dict(self.client_json_file, cdict)
             
             edict = {'ssh' : self.engine_ssh_server}
             edict.update(f.engine_info)
             edict.update(base)
             self.save_connection_dict(self.engine_json_file, edict)
 
         fname = "engines%s.json" % self.cluster_id
         self.factory.hub.engine_state_file = os.path.join(self.profile_dir.log_dir, fname)
         if self.restore_engines:
             self.factory.hub._load_engine_state()
 
     def init_schedulers(self):
         children = self.children
         mq = import_item(str(self.mq_class))
         
         f = self.factory
         ident = f.session.bsession
         # disambiguate url, in case of *
         monitor_url = disambiguate_url(f.monitor_url)
         # maybe_inproc = 'inproc://monitor' if self.use_threads else monitor_url
         # IOPub relay (in a Process)
         q = mq(zmq.PUB, zmq.SUB, zmq.PUB, b'N/A',b'iopub')
         q.bind_in(f.client_url('iopub'))
         q.setsockopt_in(zmq.IDENTITY, ident + b"_iopub")
         q.bind_out(f.engine_url('iopub'))
         q.setsockopt_out(zmq.SUBSCRIBE, b'')
         q.connect_mon(monitor_url)
         q.daemon=True
         children.append(q)
 
         # Multiplexer Queue (in a Process)
         q = mq(zmq.ROUTER, zmq.ROUTER, zmq.PUB, b'in', b'out')
         
         q.bind_in(f.client_url('mux'))
         q.setsockopt_in(zmq.IDENTITY, b'mux_in')
         q.bind_out(f.engine_url('mux'))
         q.setsockopt_out(zmq.IDENTITY, b'mux_out')
         q.connect_mon(monitor_url)
         q.daemon=True
         children.append(q)
 
         # Control Queue (in a Process)
         q = mq(zmq.ROUTER, zmq.ROUTER, zmq.PUB, b'incontrol', b'outcontrol')
         q.bind_in(f.client_url('control'))
         q.setsockopt_in(zmq.IDENTITY, b'control_in')
         q.bind_out(f.engine_url('control'))
         q.setsockopt_out(zmq.IDENTITY, b'control_out')
         q.connect_mon(monitor_url)
         q.daemon=True
         children.append(q)
-        try:
+        if 'TaskScheduler.scheme_name' in self.config:
             scheme = self.config.TaskScheduler.scheme_name
-        except AttributeError:
+        else:
             scheme = TaskScheduler.scheme_name.get_default_value()
         # Task Queue (in a Process)
         if scheme == 'pure':
             self.log.warn("task::using pure DEALER Task scheduler")
             q = mq(zmq.ROUTER, zmq.DEALER, zmq.PUB, b'intask', b'outtask')
             # q.setsockopt_out(zmq.HWM, hub.hwm)
             q.bind_in(f.client_url('task'))
             q.setsockopt_in(zmq.IDENTITY, b'task_in')
             q.bind_out(f.engine_url('task'))
             q.setsockopt_out(zmq.IDENTITY, b'task_out')
             q.connect_mon(monitor_url)
             q.daemon=True
             children.append(q)
         elif scheme == 'none':
             self.log.warn("task::using no Task scheduler")
 
         else:
             self.log.info("task::using Python %s Task scheduler"%scheme)
             sargs = (f.client_url('task'), f.engine_url('task'),
                     monitor_url, disambiguate_url(f.client_url('notification')),
                     disambiguate_url(f.client_url('registration')),
             )
             kwargs = dict(logname='scheduler', loglevel=self.log_level,
                             log_url = self.log_url, config=dict(self.config))
             if 'Process' in self.mq_class:
                 # run the Python scheduler in a Process
                 q = Process(target=launch_scheduler, args=sargs, kwargs=kwargs)
                 q.daemon=True
                 children.append(q)
             else:
                 # single-threaded Controller
                 kwargs['in_thread'] = True
                 launch_scheduler(*sargs, **kwargs)
         
         # set unlimited HWM for all relay devices
         if hasattr(zmq, 'SNDHWM'):
             q = children[0]
             q.setsockopt_in(zmq.RCVHWM, 0)
             q.setsockopt_out(zmq.SNDHWM, 0)
             
             for q in children[1:]:
                 if not hasattr(q, 'setsockopt_in'):
                     continue
                 q.setsockopt_in(zmq.SNDHWM, 0)
                 q.setsockopt_in(zmq.RCVHWM, 0)
                 q.setsockopt_out(zmq.SNDHWM, 0)
                 q.setsockopt_out(zmq.RCVHWM, 0)
                 q.setsockopt_mon(zmq.SNDHWM, 0)
             
 
     def terminate_children(self):
         child_procs = []
         for child in self.children:
             if isinstance(child, ProcessMonitoredQueue):
                 child_procs.append(child.launcher)
             elif isinstance(child, Process):
                 child_procs.append(child)
         if child_procs:
             self.log.critical("terminating children...")
             for child in child_procs:
                 try:
                     child.terminate()
                 except OSError:
                     # already dead
                     pass
     
     def handle_signal(self, sig, frame):
         self.log.critical("Received signal %i, shutting down", sig)
         self.terminate_children()
         self.loop.stop()
     
     def init_signal(self):
         for sig in (SIGINT, SIGABRT, SIGTERM):
             signal(sig, self.handle_signal)
 
     def do_import_statements(self):
         statements = self.import_statements
         for s in statements:
             try:
                 self.log.msg("Executing statement: '%s'" % s)
                 exec s in globals(), locals()
             except:
                 self.log.msg("Error running statement: %s" % s)
 
     def forward_logging(self):
         if self.log_url:
             self.log.info("Forwarding logging to %s"%self.log_url)
             context = zmq.Context.instance()
             lsock = context.socket(zmq.PUB)
             lsock.connect(self.log_url)
             handler = PUBHandler(lsock)
             handler.root_topic = 'controller'
             handler.setLevel(self.log_level)
             self.log.addHandler(handler)
     
     @catch_config_error
     def initialize(self, argv=None):
         super(IPControllerApp, self).initialize(argv)
         self.forward_logging()
         self.load_secondary_config()
         self.init_hub()
         self.init_schedulers()
     
     def start(self):
         # Start the subprocesses:
         self.factory.start()
         # children must be started before signals are setup,
         # otherwise signal-handling will fire multiple times
         for child in self.children:
             child.start()
         self.init_signal()
 
         self.write_pid_file(overwrite=True)
 
         try:
             self.factory.loop.start()
         except KeyboardInterrupt:
             self.log.critical("Interrupted, Exiting...\n")
         finally:
             self.cleanup_connection_files()
             
 
 def launch_new_instance(*args, **kwargs):
     """Create and run the IPython controller"""
     if sys.platform == 'win32':
         # make sure we don't get called from a multiprocessing subprocess
         # this can result in infinite Controllers being started on Windows
         # which doesn't have a proper fork, so multiprocessing is wonky
         
         # this only comes up when IPython has been installed using vanilla
         # setuptools, and *not* distribute.
         import multiprocessing
         p = multiprocessing.current_process()
         # the main process has name 'MainProcess'
         # subprocesses will have names like 'Process-1'
         if p.name != 'MainProcess':
             # we are a subprocess, don't start another Controller!
             return
     return IPControllerApp.launch_instance(*args, **kwargs)
 
 
 if __name__ == '__main__':
     launch_new_instance()

IPython/parallel/apps/ipengineapp.py

@@ -1,393 +1,384
 #!/usr/bin/env python
 # encoding: utf-8
 """
 The IPython engine application
 
 Authors:
 
 * Brian Granger
 * MinRK
 
 """
 
 #-----------------------------------------------------------------------------
 #  Copyright (C) 2008-2011  The IPython Development Team
 #
 #  Distributed under the terms of the BSD License.  The full license is in
 #  the file COPYING, distributed as part of this software.
 #-----------------------------------------------------------------------------
 
 #-----------------------------------------------------------------------------
 # Imports
 #-----------------------------------------------------------------------------
 
 import json
 import os
 import sys
 import time
 
 import zmq
 from zmq.eventloop import ioloop
 
 from IPython.core.profiledir import ProfileDir
 from IPython.parallel.apps.baseapp import (
     BaseParallelApplication,
     base_aliases,
     base_flags,
     catch_config_error,
 )
 from IPython.kernel.zmq.log import EnginePUBHandler
 from IPython.kernel.zmq.ipkernel import Kernel
 from IPython.kernel.zmq.kernelapp import IPKernelApp
 from IPython.kernel.zmq.session import (
     Session, session_aliases, session_flags
 )
 from IPython.kernel.zmq.zmqshell import ZMQInteractiveShell
 
 from IPython.config.configurable import Configurable
 
 from IPython.parallel.engine.engine import EngineFactory
 from IPython.parallel.util import disambiguate_ip_address
 
 from IPython.utils.importstring import import_item
 from IPython.utils.py3compat import cast_bytes
 from IPython.utils.traitlets import Bool, Unicode, Dict, List, Float, Instance
 
 
 #-----------------------------------------------------------------------------
 # Module level variables
 #-----------------------------------------------------------------------------
 
 _description = """Start an IPython engine for parallel computing.
 
 IPython engines run in parallel and perform computations on behalf of a client
 and controller. A controller needs to be started before the engines. The
 engine can be configured using command line options or using a cluster
 directory. Cluster directories contain config, log and security files and are
 usually located in your ipython directory and named as "profile_name".
 See the `profile` and `profile-dir` options for details.
 """
 
 _examples = """
 ipengine --ip=192.168.0.1 --port=1000     # connect to hub at ip and port
 ipengine --log-to-file --log-level=DEBUG  # log to a file with DEBUG verbosity
 """
 
 #-----------------------------------------------------------------------------
 # MPI configuration
 #-----------------------------------------------------------------------------
 
 mpi4py_init = """from mpi4py import MPI as mpi
 mpi.size = mpi.COMM_WORLD.Get_size()
 mpi.rank = mpi.COMM_WORLD.Get_rank()
 """
 
 
 pytrilinos_init = """from PyTrilinos import Epetra
 class SimpleStruct:
 pass
 mpi = SimpleStruct()
 mpi.rank = 0
 mpi.size = 0
 """
 
 class MPI(Configurable):
     """Configurable for MPI initialization"""
     use = Unicode('', config=True,
         help='How to enable MPI (mpi4py, pytrilinos, or empty string to disable).'
         )
 
     def _use_changed(self, name, old, new):
         # load default init script if it's not set
         if not self.init_script:
             self.init_script = self.default_inits.get(new, '')
 
     init_script = Unicode('', config=True,
         help="Initialization code for MPI")
 
     default_inits = Dict({'mpi4py' : mpi4py_init, 'pytrilinos':pytrilinos_init},
         config=True)
 
 
 #-----------------------------------------------------------------------------
 # Main application
 #-----------------------------------------------------------------------------
 aliases = dict(
     file = 'IPEngineApp.url_file',
     c = 'IPEngineApp.startup_command',
     s = 'IPEngineApp.startup_script',
 
     url = 'EngineFactory.url',
     ssh = 'EngineFactory.sshserver',
     sshkey = 'EngineFactory.sshkey',
     ip = 'EngineFactory.ip',
     transport = 'EngineFactory.transport',
     port = 'EngineFactory.regport',
     location = 'EngineFactory.location',
 
     timeout = 'EngineFactory.timeout',
 
     mpi = 'MPI.use',
 
 )
 aliases.update(base_aliases)
 aliases.update(session_aliases)
 flags = {}
 flags.update(base_flags)
 flags.update(session_flags)
 
 class IPEngineApp(BaseParallelApplication):
 
     name = 'ipengine'
     description = _description
     examples = _examples
     classes = List([ZMQInteractiveShell, ProfileDir, Session, EngineFactory, Kernel, MPI])
 
     startup_script = Unicode(u'', config=True,
         help='specify a script to be run at startup')
     startup_command = Unicode('', config=True,
             help='specify a command to be run at startup')
 
     url_file = Unicode(u'', config=True,
         help="""The full location of the file containing the connection information for
         the controller. If this is not given, the file must be in the
         security directory of the cluster directory.  This location is
         resolved using the `profile` or `profile_dir` options.""",
         )
     wait_for_url_file = Float(5, config=True,
         help="""The maximum number of seconds to wait for url_file to exist.
         This is useful for batch-systems and shared-filesystems where the
         controller and engine are started at the same time and it
         may take a moment for the controller to write the connector files.""")
 
     url_file_name = Unicode(u'ipcontroller-engine.json', config=True)
 
     def _cluster_id_changed(self, name, old, new):
         if new:
             base = 'ipcontroller-%s' % new
         else:
             base = 'ipcontroller'
         self.url_file_name = "%s-engine.json" % base
 
     log_url = Unicode('', config=True,
         help="""The URL for the iploggerapp instance, for forwarding
         logging to a central location.""")
     
     # an IPKernelApp instance, used to setup listening for shell frontends
     kernel_app = Instance(IPKernelApp)
 
     aliases = Dict(aliases)
     flags = Dict(flags)
     
     @property
     def kernel(self):
         """allow access to the Kernel object, so I look like IPKernelApp"""
         return self.engine.kernel
 
     def find_url_file(self):
         """Set the url file.
 
         Here we don't try to actually see if it exists for is valid as that
         is hadled by the connection logic.
         """
         config = self.config
         # Find the actual controller key file
         if not self.url_file:
             self.url_file = os.path.join(
                 self.profile_dir.security_dir,
                 self.url_file_name
             )
     
     def load_connector_file(self):
         """load config from a JSON connector file,
         at a *lower* priority than command-line/config files.
         """
         
         self.log.info("Loading url_file %r", self.url_file)
         config = self.config
         
         with open(self.url_file) as f:
             d = json.loads(f.read())
         
         # allow hand-override of location for disambiguation
         # and ssh-server
-        try:
-            config.EngineFactory.location
-        except AttributeError:
+        if 'EngineFactory.location' not in config:
             config.EngineFactory.location = d['location']
-        
-        try:
-            config.EngineFactory.sshserver
-        except AttributeError:
+        if 'EngineFactory.sshserver' not in config:
             config.EngineFactory.sshserver = d.get('ssh')
         
         location = config.EngineFactory.location
         
         proto, ip = d['interface'].split('://')
         ip = disambiguate_ip_address(ip, location)
         d['interface'] = '%s://%s' % (proto, ip)
         
         # DO NOT allow override of basic URLs, serialization, or key
         # JSON file takes top priority there
         config.Session.key = cast_bytes(d['key'])
         config.Session.signature_scheme = d['signature_scheme']
         
         config.EngineFactory.url = d['interface'] + ':%i' % d['registration']
         
         config.Session.packer = d['pack']
         config.Session.unpacker = d['unpack']
         
         self.log.debug("Config changed:")
         self.log.debug("%r", config)
         self.connection_info = d
     
     def bind_kernel(self, **kwargs):
         """Promote engine to listening kernel, accessible to frontends."""
         if self.kernel_app is not None:
             return
         
         self.log.info("Opening ports for direct connections as an IPython kernel")
         
         kernel = self.kernel
         
         kwargs.setdefault('config', self.config)
         kwargs.setdefault('log', self.log)
         kwargs.setdefault('profile_dir', self.profile_dir)
         kwargs.setdefault('session', self.engine.session)
         
         app = self.kernel_app = IPKernelApp(**kwargs)
         
         # allow IPKernelApp.instance():
         IPKernelApp._instance = app
         
         app.init_connection_file()
         # relevant contents of init_sockets:
         
         app.shell_port = app._bind_socket(kernel.shell_streams[0], app.shell_port)
         app.log.debug("shell ROUTER Channel on port: %i", app.shell_port)
         
         app.iopub_port = app._bind_socket(kernel.iopub_socket, app.iopub_port)
         app.log.debug("iopub PUB Channel on port: %i", app.iopub_port)
         
         kernel.stdin_socket = self.engine.context.socket(zmq.ROUTER)
         app.stdin_port = app._bind_socket(kernel.stdin_socket, app.stdin_port)
         app.log.debug("stdin ROUTER Channel on port: %i", app.stdin_port)
         
         # start the heartbeat, and log connection info:
         
         app.init_heartbeat()
         
         app.log_connection_info()
         app.write_connection_file()
         
     
     def init_engine(self):
         # This is the working dir by now.
         sys.path.insert(0, '')
         config = self.config
         # print config
         self.find_url_file()
         
         # was the url manually specified?
         keys = set(self.config.EngineFactory.keys())
         keys = keys.union(set(self.config.RegistrationFactory.keys()))
         
         if keys.intersection(set(['ip', 'url', 'port'])):
             # Connection info was specified, don't wait for the file
             url_specified = True
             self.wait_for_url_file = 0
         else:
             url_specified = False
 
         if self.wait_for_url_file and not os.path.exists(self.url_file):
             self.log.warn("url_file %r not found", self.url_file)
             self.log.warn("Waiting up to %.1f seconds for it to arrive.", self.wait_for_url_file)
             tic = time.time()
             while not os.path.exists(self.url_file) and (time.time()-tic < self.wait_for_url_file):
                 # wait for url_file to exist, or until time limit
                 time.sleep(0.1)
             
         if os.path.exists(self.url_file):
             self.load_connector_file()
         elif not url_specified:
             self.log.fatal("Fatal: url file never arrived: %s", self.url_file)
             self.exit(1)
         
-        
-        try:
-            exec_lines = config.IPKernelApp.exec_lines
-        except AttributeError:
-            try:
-                exec_lines = config.InteractiveShellApp.exec_lines
-            except AttributeError:
-                exec_lines = config.IPKernelApp.exec_lines = []
-        try:
-            exec_files = config.IPKernelApp.exec_files
-        except AttributeError:
-            try:
-                exec_files = config.InteractiveShellApp.exec_files
-            except AttributeError:
-                exec_files = config.IPKernelApp.exec_files = []
+        exec_lines = []
+        for app in ('IPKernelApp', 'InteractiveShellApp'):
+            if '%s.exec_lines' in config:
+                exec_lines = config.IPKernelApp.exec_lines = config[app].exec_lines
+                break
+        
+        exec_files = []
+        for app in ('IPKernelApp', 'InteractiveShellApp'):
+            if '%s.exec_files' in config:
+                exec_files = config.IPKernelApp.exec_files = config[app].exec_files
+                break
         
         if self.startup_script:
             exec_files.append(self.startup_script)
         if self.startup_command:
             exec_lines.append(self.startup_command)
 
         # Create the underlying shell class and Engine
         # shell_class = import_item(self.master_config.Global.shell_class)
         # print self.config
         try:
             self.engine = EngineFactory(config=config, log=self.log,
                             connection_info=self.connection_info,
                         )
         except:
             self.log.error("Couldn't start the Engine", exc_info=True)
             self.exit(1)
     
     def forward_logging(self):
         if self.log_url:
             self.log.info("Forwarding logging to %s", self.log_url)
             context = self.engine.context
             lsock = context.socket(zmq.PUB)
             lsock.connect(self.log_url)
             handler = EnginePUBHandler(self.engine, lsock)
             handler.setLevel(self.log_level)
             self.log.addHandler(handler)
     
     def init_mpi(self):
         global mpi
         self.mpi = MPI(parent=self)
 
         mpi_import_statement = self.mpi.init_script
         if mpi_import_statement:
             try:
                 self.log.info("Initializing MPI:")
                 self.log.info(mpi_import_statement)
                 exec mpi_import_statement in globals()
             except:
                 mpi = None
         else:
             mpi = None
 
     @catch_config_error
     def initialize(self, argv=None):
         super(IPEngineApp, self).initialize(argv)
         self.init_mpi()
         self.init_engine()
         self.forward_logging()
     
     def start(self):
         self.engine.start()
         try:
             self.engine.loop.start()
         except KeyboardInterrupt:
             self.log.critical("Engine Interrupted, shutting down...\n")
 
 
 launch_new_instance = IPEngineApp.launch_instance
 
 
 if __name__ == '__main__':
     launch_new_instance()
 

IPython/parallel/controller/hub.py

@@ -1,1422 +1,1421
 """The IPython Controller Hub with 0MQ
 This is the master object that handles connections from engines and clients,
 and monitors traffic through the various queues.
 
 Authors:
 
 * Min RK
 """
 #-----------------------------------------------------------------------------
 #  Copyright (C) 2010-2011  The IPython Development Team
 #
 #  Distributed under the terms of the BSD License.  The full license is in
 #  the file COPYING, distributed as part of this software.
 #-----------------------------------------------------------------------------
 
 #-----------------------------------------------------------------------------
 # Imports
 #-----------------------------------------------------------------------------
 from __future__ import print_function
 
 import json
 import os
 import sys
 import time
 from datetime import datetime
 
 import zmq
 from zmq.eventloop import ioloop
 from zmq.eventloop.zmqstream import ZMQStream
 
 # internal:
 from IPython.utils.importstring import import_item
 from IPython.utils.localinterfaces import localhost
 from IPython.utils.py3compat import cast_bytes
 from IPython.utils.traitlets import (
         HasTraits, Instance, Integer, Unicode, Dict, Set, Tuple, CBytes, DottedObjectName
         )
 
 from IPython.parallel import error, util
 from IPython.parallel.factory import RegistrationFactory
 
 from IPython.kernel.zmq.session import SessionFactory
 
 from .heartmonitor import HeartMonitor
 
 #-----------------------------------------------------------------------------
 # Code
 #-----------------------------------------------------------------------------
 
 def _passer(*args, **kwargs):
     return
 
 def _printer(*args, **kwargs):
     print (args)
     print (kwargs)
 
 def empty_record():
     """Return an empty dict with all record keys."""
     return {
         'msg_id' : None,
         'header' : None,
         'metadata' : None,
         'content': None,
         'buffers': None,
         'submitted': None,
         'client_uuid' : None,
         'engine_uuid' : None,
         'started': None,
         'completed': None,
         'resubmitted': None,
         'received': None,
         'result_header' : None,
         'result_metadata' : None,
         'result_content' : None,
         'result_buffers' : None,
         'queue' : None,
         'pyin' : None,
         'pyout': None,
         'pyerr': None,
         'stdout': '',
         'stderr': '',
     }
 
 def init_record(msg):
     """Initialize a TaskRecord based on a request."""
     header = msg['header']
     return {
         'msg_id' : header['msg_id'],
         'header' : header,
         'content': msg['content'],
         'metadata': msg['metadata'],
         'buffers': msg['buffers'],
         'submitted': header['date'],
         'client_uuid' : None,
         'engine_uuid' : None,
         'started': None,
         'completed': None,
         'resubmitted': None,
         'received': None,
         'result_header' : None,
         'result_metadata': None,
         'result_content' : None,
         'result_buffers' : None,
         'queue' : None,
         'pyin' : None,
         'pyout': None,
         'pyerr': None,
         'stdout': '',
         'stderr': '',
     }
 
 
 class EngineConnector(HasTraits):
     """A simple object for accessing the various zmq connections of an object.
     Attributes are:
     id (int): engine ID
     uuid (unicode): engine UUID
     pending: set of msg_ids
     stallback: DelayedCallback for stalled registration
     """
     
     id = Integer(0)
     uuid = Unicode()
     pending = Set()
     stallback = Instance(ioloop.DelayedCallback)
 
 
 _db_shortcuts = {
     'sqlitedb' : 'IPython.parallel.controller.sqlitedb.SQLiteDB',
     'mongodb'  : 'IPython.parallel.controller.mongodb.MongoDB',
     'dictdb'   : 'IPython.parallel.controller.dictdb.DictDB',
     'nodb'     : 'IPython.parallel.controller.dictdb.NoDB',
 }
 
 class HubFactory(RegistrationFactory):
     """The Configurable for setting up a Hub."""
 
     # port-pairs for monitoredqueues:
     hb = Tuple(Integer,Integer,config=True,
         help="""PUB/ROUTER Port pair for Engine heartbeats""")
     def _hb_default(self):
         return tuple(util.select_random_ports(2))
 
     mux = Tuple(Integer,Integer,config=True,
         help="""Client/Engine Port pair for MUX queue""")
 
     def _mux_default(self):
         return tuple(util.select_random_ports(2))
 
     task = Tuple(Integer,Integer,config=True,
         help="""Client/Engine Port pair for Task queue""")
     def _task_default(self):
         return tuple(util.select_random_ports(2))
 
     control = Tuple(Integer,Integer,config=True,
         help="""Client/Engine Port pair for Control queue""")
 
     def _control_default(self):
         return tuple(util.select_random_ports(2))
 
     iopub = Tuple(Integer,Integer,config=True,
         help="""Client/Engine Port pair for IOPub relay""")
 
     def _iopub_default(self):
         return tuple(util.select_random_ports(2))
 
     # single ports:
     mon_port = Integer(config=True,
         help="""Monitor (SUB) port for queue traffic""")
 
     def _mon_port_default(self):
         return util.select_random_ports(1)[0]
 
     notifier_port = Integer(config=True,
         help="""PUB port for sending engine status notifications""")
 
     def _notifier_port_default(self):
         return util.select_random_ports(1)[0]
 
     engine_ip = Unicode(config=True,
         help="IP on which to listen for engine connections. [default: loopback]")
     def _engine_ip_default(self):
         return localhost()
     engine_transport = Unicode('tcp', config=True,
         help="0MQ transport for engine connections. [default: tcp]")
 
     client_ip = Unicode(config=True,
         help="IP on which to listen for client connections. [default: loopback]")
     client_transport = Unicode('tcp', config=True,
         help="0MQ transport for client connections. [default : tcp]")
 
     monitor_ip = Unicode(config=True,
         help="IP on which to listen for monitor messages. [default: loopback]")
     monitor_transport = Unicode('tcp', config=True,
         help="0MQ transport for monitor messages. [default : tcp]")
     
     _client_ip_default = _monitor_ip_default = _engine_ip_default
     
 
     monitor_url = Unicode('')
 
     db_class = DottedObjectName('NoDB',
         config=True, help="""The class to use for the DB backend
         
         Options include:
         
         SQLiteDB: SQLite
         MongoDB : use MongoDB
         DictDB  : in-memory storage (fastest, but be mindful of memory growth of the Hub)
         NoDB    : disable database altogether (default)
         
         """)
 
     # not configurable
     db = Instance('IPython.parallel.controller.dictdb.BaseDB')
     heartmonitor = Instance('IPython.parallel.controller.heartmonitor.HeartMonitor')
 
     def _ip_changed(self, name, old, new):
         self.engine_ip = new
         self.client_ip = new
         self.monitor_ip = new
         self._update_monitor_url()
 
     def _update_monitor_url(self):
         self.monitor_url = "%s://%s:%i" % (self.monitor_transport, self.monitor_ip, self.mon_port)
 
     def _transport_changed(self, name, old, new):
         self.engine_transport = new
         self.client_transport = new
         self.monitor_transport = new
         self._update_monitor_url()
 
     def __init__(self, **kwargs):
         super(HubFactory, self).__init__(**kwargs)
         self._update_monitor_url()
 
 
     def construct(self):
         self.init_hub()
 
     def start(self):
         self.heartmonitor.start()
         self.log.info("Heartmonitor started")
 
     def client_url(self, channel):
         """return full zmq url for a named client channel"""
         return "%s://%s:%i" % (self.client_transport, self.client_ip, self.client_info[channel])
     
     def engine_url(self, channel):
         """return full zmq url for a named engine channel"""
         return "%s://%s:%i" % (self.engine_transport, self.engine_ip, self.engine_info[channel])
     
     def init_hub(self):
         """construct Hub object"""
 
         ctx = self.context
         loop = self.loop
-
-        try:
+        if 'TaskScheduler.scheme_name' in self.config:
             scheme = self.config.TaskScheduler.scheme_name
-        except AttributeError:
+        else:
             from .scheduler import TaskScheduler
             scheme = TaskScheduler.scheme_name.get_default_value()
         
         # build connection dicts
         engine = self.engine_info = {
             'interface'     : "%s://%s" % (self.engine_transport, self.engine_ip),
             'registration'  : self.regport,
             'control'       : self.control[1],
             'mux'           : self.mux[1],
             'hb_ping'       : self.hb[0],
             'hb_pong'       : self.hb[1],
             'task'          : self.task[1],
             'iopub'         : self.iopub[1],
             }
 
         client = self.client_info = {
             'interface'     : "%s://%s" % (self.client_transport, self.client_ip),
             'registration'  : self.regport,
             'control'       : self.control[0],
             'mux'           : self.mux[0],
             'task'          : self.task[0],
             'task_scheme'   : scheme,
             'iopub'         : self.iopub[0],
             'notification'  : self.notifier_port,
             }
         
         self.log.debug("Hub engine addrs: %s", self.engine_info)
         self.log.debug("Hub client addrs: %s", self.client_info)
         
         # Registrar socket
         q = ZMQStream(ctx.socket(zmq.ROUTER), loop)
         util.set_hwm(q, 0)
         q.bind(self.client_url('registration'))
         self.log.info("Hub listening on %s for registration.", self.client_url('registration'))
         if self.client_ip != self.engine_ip:
             q.bind(self.engine_url('registration'))
             self.log.info("Hub listening on %s for registration.", self.engine_url('registration'))
 
         ### Engine connections ###
 
         # heartbeat
         hpub = ctx.socket(zmq.PUB)
         hpub.bind(self.engine_url('hb_ping'))
         hrep = ctx.socket(zmq.ROUTER)
         util.set_hwm(hrep, 0)
         hrep.bind(self.engine_url('hb_pong'))
         self.heartmonitor = HeartMonitor(loop=loop, parent=self, log=self.log,
                                 pingstream=ZMQStream(hpub,loop),
                                 pongstream=ZMQStream(hrep,loop)
                             )
 
         ### Client connections ###
         
         # Notifier socket
         n = ZMQStream(ctx.socket(zmq.PUB), loop)
         n.bind(self.client_url('notification'))
 
         ### build and launch the queues ###
 
         # monitor socket
         sub = ctx.socket(zmq.SUB)
         sub.setsockopt(zmq.SUBSCRIBE, b"")
         sub.bind(self.monitor_url)
         sub.bind('inproc://monitor')
         sub = ZMQStream(sub, loop)
 
         # connect the db
         db_class = _db_shortcuts.get(self.db_class.lower(), self.db_class)
         self.log.info('Hub using DB backend: %r', (db_class.split('.')[-1]))
         self.db = import_item(str(db_class))(session=self.session.session,
                                             parent=self, log=self.log)
         time.sleep(.25)
 
         # resubmit stream
         r = ZMQStream(ctx.socket(zmq.DEALER), loop)
         url = util.disambiguate_url(self.client_url('task'))
         r.connect(url)
 
         self.hub = Hub(loop=loop, session=self.session, monitor=sub, heartmonitor=self.heartmonitor,
                 query=q, notifier=n, resubmit=r, db=self.db,
                 engine_info=self.engine_info, client_info=self.client_info,
                 log=self.log)
 
 
 class Hub(SessionFactory):
     """The IPython Controller Hub with 0MQ connections
 
     Parameters
     ==========
     loop: zmq IOLoop instance
     session: Session object
     <removed> context: zmq context for creating new connections (?)
     queue: ZMQStream for monitoring the command queue (SUB)
     query: ZMQStream for engine registration and client queries requests (ROUTER)
     heartbeat: HeartMonitor object checking the pulse of the engines
     notifier: ZMQStream for broadcasting engine registration changes (PUB)
     db: connection to db for out of memory logging of commands
                 NotImplemented
     engine_info: dict of zmq connection information for engines to connect
                 to the queues.
     client_info: dict of zmq connection information for engines to connect
                 to the queues.
     """
     
     engine_state_file = Unicode()
     
     # internal data structures:
     ids=Set() # engine IDs
     keytable=Dict()
     by_ident=Dict()
     engines=Dict()
     clients=Dict()
     hearts=Dict()
     pending=Set()
     queues=Dict()  # pending msg_ids keyed by engine_id
     tasks=Dict() # pending msg_ids submitted as tasks, keyed by client_id
     completed=Dict() # completed msg_ids keyed by engine_id
     all_completed=Set() # completed msg_ids keyed by engine_id
     dead_engines=Set() # completed msg_ids keyed by engine_id
     unassigned=Set() # set of task msg_ds not yet assigned a destination
     incoming_registrations=Dict()
     registration_timeout=Integer()
     _idcounter=Integer(0)
 
     # objects from constructor:
     query=Instance(ZMQStream)
     monitor=Instance(ZMQStream)
     notifier=Instance(ZMQStream)
     resubmit=Instance(ZMQStream)
     heartmonitor=Instance(HeartMonitor)
     db=Instance(object)
     client_info=Dict()
     engine_info=Dict()
 
 
     def __init__(self, **kwargs):
         """
         # universal:
         loop: IOLoop for creating future connections
         session: streamsession for sending serialized data
         # engine:
         queue: ZMQStream for monitoring queue messages
         query: ZMQStream for engine+client registration and client requests
         heartbeat: HeartMonitor object for tracking engines
         # extra:
         db: ZMQStream for db connection (NotImplemented)
         engine_info: zmq address/protocol dict for engine connections
         client_info: zmq address/protocol dict for client connections
         """
 
         super(Hub, self).__init__(**kwargs)
         self.registration_timeout = max(10000, 5*self.heartmonitor.period)
 
         # register our callbacks
         self.query.on_recv(self.dispatch_query)
         self.monitor.on_recv(self.dispatch_monitor_traffic)
 
         self.heartmonitor.add_heart_failure_handler(self.handle_heart_failure)
         self.heartmonitor.add_new_heart_handler(self.handle_new_heart)
 
         self.monitor_handlers = {b'in' : self.save_queue_request,
                                 b'out': self.save_queue_result,
                                 b'intask': self.save_task_request,
                                 b'outtask': self.save_task_result,
                                 b'tracktask': self.save_task_destination,
                                 b'incontrol': _passer,
                                 b'outcontrol': _passer,
                                 b'iopub': self.save_iopub_message,
         }
 
         self.query_handlers = {'queue_request': self.queue_status,
                                 'result_request': self.get_results,
                                 'history_request': self.get_history,
                                 'db_request': self.db_query,
                                 'purge_request': self.purge_results,
                                 'load_request': self.check_load,
                                 'resubmit_request': self.resubmit_task,
                                 'shutdown_request': self.shutdown_request,
                                 'registration_request' : self.register_engine,
                                 'unregistration_request' : self.unregister_engine,
                                 'connection_request': self.connection_request,
         }
 
         # ignore resubmit replies
         self.resubmit.on_recv(lambda msg: None, copy=False)
 
         self.log.info("hub::created hub")
     
     @property
     def _next_id(self):
         """gemerate a new ID.
 
         No longer reuse old ids, just count from 0."""
         newid = self._idcounter
         self._idcounter += 1
         return newid
         # newid = 0
         # incoming = [id[0] for id in self.incoming_registrations.itervalues()]
         # # print newid, self.ids, self.incoming_registrations
         # while newid in self.ids or newid in incoming:
         #     newid += 1
         # return newid
     
     #-----------------------------------------------------------------------------
     # message validation
     #-----------------------------------------------------------------------------
 
     def _validate_targets(self, targets):
         """turn any valid targets argument into a list of integer ids"""
         if targets is None:
             # default to all
             return self.ids
 
         if isinstance(targets, (int,str,unicode)):
             # only one target specified
             targets = [targets]
         _targets = []
         for t in targets:
             # map raw identities to ids
             if isinstance(t, (str,unicode)):
                 t = self.by_ident.get(cast_bytes(t), t)
             _targets.append(t)
         targets = _targets
         bad_targets = [ t for t in targets if t not in self.ids ]
         if bad_targets:
             raise IndexError("No Such Engine: %r" % bad_targets)
         if not targets:
             raise IndexError("No Engines Registered")
         return targets
 
     #-----------------------------------------------------------------------------
     # dispatch methods (1 per stream)
     #-----------------------------------------------------------------------------
 
 
     @util.log_errors
     def dispatch_monitor_traffic(self, msg):
         """all ME and Task queue messages come through here, as well as
         IOPub traffic."""
         self.log.debug("monitor traffic: %r", msg[0])
         switch = msg[0]
         try:
             idents, msg = self.session.feed_identities(msg[1:])
         except ValueError:
             idents=[]
         if not idents:
             self.log.error("Monitor message without topic: %r", msg)
             return
         handler = self.monitor_handlers.get(switch, None)
         if handler is not None:
             handler(idents, msg)
         else:
             self.log.error("Unrecognized monitor topic: %r", switch)
 
 
     @util.log_errors
     def dispatch_query(self, msg):
         """Route registration requests and queries from clients."""
         try:
             idents, msg = self.session.feed_identities(msg)
         except ValueError:
             idents = []
         if not idents:
             self.log.error("Bad Query Message: %r", msg)
             return
         client_id = idents[0]
         try:
             msg = self.session.unserialize(msg, content=True)
         except Exception:
             content = error.wrap_exception()
             self.log.error("Bad Query Message: %r", msg, exc_info=True)
             self.session.send(self.query, "hub_error", ident=client_id,
                     content=content)
             return
         # print client_id, header, parent, content
         #switch on message type:
         msg_type = msg['header']['msg_type']
         self.log.info("client::client %r requested %r", client_id, msg_type)
         handler = self.query_handlers.get(msg_type, None)
         try:
             assert handler is not None, "Bad Message Type: %r" % msg_type
         except:
             content = error.wrap_exception()
             self.log.error("Bad Message Type: %r", msg_type, exc_info=True)
             self.session.send(self.query, "hub_error", ident=client_id,
                     content=content)
             return
 
         else:
             handler(idents, msg)
 
     def dispatch_db(self, msg):
         """"""
         raise NotImplementedError
 
     #---------------------------------------------------------------------------
     # handler methods (1 per event)
     #---------------------------------------------------------------------------
 
     #----------------------- Heartbeat --------------------------------------
 
     def handle_new_heart(self, heart):
         """handler to attach to heartbeater.
         Called when a new heart starts to beat.
         Triggers completion of registration."""
         self.log.debug("heartbeat::handle_new_heart(%r)", heart)
         if heart not in self.incoming_registrations:
             self.log.info("heartbeat::ignoring new heart: %r", heart)
         else:
             self.finish_registration(heart)
 
 
     def handle_heart_failure(self, heart):
         """handler to attach to heartbeater.
         called when a previously registered heart fails to respond to beat request.
         triggers unregistration"""
         self.log.debug("heartbeat::handle_heart_failure(%r)", heart)
         eid = self.hearts.get(heart, None)
         uuid = self.engines[eid].uuid
         if eid is None or self.keytable[eid] in self.dead_engines:
             self.log.info("heartbeat::ignoring heart failure %r (not an engine or already dead)", heart)
         else:
             self.unregister_engine(heart, dict(content=dict(id=eid, queue=uuid)))
 
     #----------------------- MUX Queue Traffic ------------------------------
 
     def save_queue_request(self, idents, msg):
         if len(idents) < 2:
             self.log.error("invalid identity prefix: %r", idents)
             return
         queue_id, client_id = idents[:2]
         try:
             msg = self.session.unserialize(msg)
         except Exception:
             self.log.error("queue::client %r sent invalid message to %r: %r", client_id, queue_id, msg, exc_info=True)
             return
 
         eid = self.by_ident.get(queue_id, None)
         if eid is None:
             self.log.error("queue::target %r not registered", queue_id)
             self.log.debug("queue::    valid are: %r", self.by_ident.keys())
             return
         record = init_record(msg)
         msg_id = record['msg_id']
         self.log.info("queue::client %r submitted request %r to %s", client_id, msg_id, eid)
         # Unicode in records
         record['engine_uuid'] = queue_id.decode('ascii')
         record['client_uuid'] = msg['header']['session']
         record['queue'] = 'mux'
 
         try:
             # it's posible iopub arrived first:
             existing = self.db.get_record(msg_id)
             for key,evalue in existing.iteritems():
                 rvalue = record.get(key, None)
                 if evalue and rvalue and evalue != rvalue:
                     self.log.warn("conflicting initial state for record: %r:%r <%r> %r", msg_id, rvalue, key, evalue)
                 elif evalue and not rvalue:
                     record[key] = evalue
             try:
                 self.db.update_record(msg_id, record)
             except Exception:
                 self.log.error("DB Error updating record %r", msg_id, exc_info=True)
         except KeyError:
             try:
                 self.db.add_record(msg_id, record)
             except Exception:
                 self.log.error("DB Error adding record %r", msg_id, exc_info=True)
 
 
         self.pending.add(msg_id)
         self.queues[eid].append(msg_id)
 
     def save_queue_result(self, idents, msg):
         if len(idents) < 2:
             self.log.error("invalid identity prefix: %r", idents)
             return
 
         client_id, queue_id = idents[:2]
         try:
             msg = self.session.unserialize(msg)
         except Exception:
             self.log.error("queue::engine %r sent invalid message to %r: %r",
                     queue_id, client_id, msg, exc_info=True)
             return
 
         eid = self.by_ident.get(queue_id, None)
         if eid is None:
             self.log.error("queue::unknown engine %r is sending a reply: ", queue_id)
             return
 
         parent = msg['parent_header']
         if not parent:
             return
         msg_id = parent['msg_id']
         if msg_id in self.pending:
             self.pending.remove(msg_id)
             self.all_completed.add(msg_id)
             self.queues[eid].remove(msg_id)
             self.completed[eid].append(msg_id)
             self.log.info("queue::request %r completed on %s", msg_id, eid)
         elif msg_id not in self.all_completed:
             # it could be a result from a dead engine that died before delivering the
             # result
             self.log.warn("queue:: unknown msg finished %r", msg_id)
             return
         # update record anyway, because the unregistration could have been premature
         rheader = msg['header']
         md = msg['metadata']
         completed = rheader['date']
         started = md.get('started', None)
         result = {
             'result_header' : rheader,
             'result_metadata': md,
             'result_content': msg['content'],
             'received': datetime.now(),
             'started' : started,
             'completed' : completed
         }
 
         result['result_buffers'] = msg['buffers']
         try:
             self.db.update_record(msg_id, result)
         except Exception:
             self.log.error("DB Error updating record %r", msg_id, exc_info=True)
 
 
     #--------------------- Task Queue Traffic ------------------------------
 
     def save_task_request(self, idents, msg):
         """Save the submission of a task."""
         client_id = idents[0]
 
         try:
             msg = self.session.unserialize(msg)
         except Exception:
             self.log.error("task::client %r sent invalid task message: %r",
                     client_id, msg, exc_info=True)
             return
         record = init_record(msg)
 
         record['client_uuid'] = msg['header']['session']
         record['queue'] = 'task'
         header = msg['header']
         msg_id = header['msg_id']
         self.pending.add(msg_id)
         self.unassigned.add(msg_id)
         try:
             # it's posible iopub arrived first:
             existing = self.db.get_record(msg_id)
             if existing['resubmitted']:
                 for key in ('submitted', 'client_uuid', 'buffers'):
                     # don't clobber these keys on resubmit
                     # submitted and client_uuid should be different
                     # and buffers might be big, and shouldn't have changed
                     record.pop(key)
                     # still check content,header which should not change
                     # but are not expensive to compare as buffers
 
             for key,evalue in existing.iteritems():
                 if key.endswith('buffers'):
                     # don't compare buffers
                     continue
                 rvalue = record.get(key, None)
                 if evalue and rvalue and evalue != rvalue:
                     self.log.warn("conflicting initial state for record: %r:%r <%r> %r", msg_id, rvalue, key, evalue)
                 elif evalue and not rvalue:
                     record[key] = evalue
             try:
                 self.db.update_record(msg_id, record)
             except Exception:
                 self.log.error("DB Error updating record %r", msg_id, exc_info=True)
         except KeyError:
             try:
                 self.db.add_record(msg_id, record)
             except Exception:
                 self.log.error("DB Error adding record %r", msg_id, exc_info=True)
         except Exception:
             self.log.error("DB Error saving task request %r", msg_id, exc_info=True)
 
     def save_task_result(self, idents, msg):
         """save the result of a completed task."""
         client_id = idents[0]
         try:
             msg = self.session.unserialize(msg)
         except Exception:
             self.log.error("task::invalid task result message send to %r: %r",
                     client_id, msg, exc_info=True)
             return
 
         parent = msg['parent_header']
         if not parent:
             # print msg
             self.log.warn("Task %r had no parent!", msg)
             return
         msg_id = parent['msg_id']
         if msg_id in self.unassigned:
             self.unassigned.remove(msg_id)
 
         header = msg['header']
         md = msg['metadata']
         engine_uuid = md.get('engine', u'')
         eid = self.by_ident.get(cast_bytes(engine_uuid), None)
         
         status = md.get('status', None)
 
         if msg_id in self.pending:
             self.log.info("task::task %r finished on %s", msg_id, eid)
             self.pending.remove(msg_id)
             self.all_completed.add(msg_id)
             if eid is not None:
                 if status != 'aborted':
                     self.completed[eid].append(msg_id)
                 if msg_id in self.tasks[eid]:
                     self.tasks[eid].remove(msg_id)
             completed = header['date']
             started = md.get('started', None)
             result = {
                 'result_header' : header,
                 'result_metadata': msg['metadata'],
                 'result_content': msg['content'],
                 'started' : started,
                 'completed' : completed,
                 'received' : datetime.now(),
                 'engine_uuid': engine_uuid,
             }
 
             result['result_buffers'] = msg['buffers']
             try:
                 self.db.update_record(msg_id, result)
             except Exception:
                 self.log.error("DB Error saving task request %r", msg_id, exc_info=True)
 
         else:
             self.log.debug("task::unknown task %r finished", msg_id)
 
     def save_task_destination(self, idents, msg):
         try:
             msg = self.session.unserialize(msg, content=True)
         except Exception:
             self.log.error("task::invalid task tracking message", exc_info=True)
             return
         content = msg['content']
         # print (content)
         msg_id = content['msg_id']
         engine_uuid = content['engine_id']
         eid = self.by_ident[cast_bytes(engine_uuid)]
 
         self.log.info("task::task %r arrived on %r", msg_id, eid)
         if msg_id in self.unassigned:
             self.unassigned.remove(msg_id)
         # else:
         #     self.log.debug("task::task %r not listed as MIA?!"%(msg_id))
 
         self.tasks[eid].append(msg_id)
         # self.pending[msg_id][1].update(received=datetime.now(),engine=(eid,engine_uuid))
         try:
             self.db.update_record(msg_id, dict(engine_uuid=engine_uuid))
         except Exception:
             self.log.error("DB Error saving task destination %r", msg_id, exc_info=True)
 
 
     def mia_task_request(self, idents, msg):
         raise NotImplementedError
         client_id = idents[0]
         # content = dict(mia=self.mia,status='ok')
         # self.session.send('mia_reply', content=content, idents=client_id)
 
 
     #--------------------- IOPub Traffic ------------------------------
 
     def save_iopub_message(self, topics, msg):
         """save an iopub message into the db"""
         # print (topics)
         try:
             msg = self.session.unserialize(msg, content=True)
         except Exception:
             self.log.error("iopub::invalid IOPub message", exc_info=True)
             return
 
         parent = msg['parent_header']
         if not parent:
             self.log.warn("iopub::IOPub message lacks parent: %r", msg)
             return
         msg_id = parent['msg_id']
         msg_type = msg['header']['msg_type']
         content = msg['content']
 
         # ensure msg_id is in db
         try:
             rec = self.db.get_record(msg_id)
         except KeyError:
             rec = empty_record()
             rec['msg_id'] = msg_id
             self.db.add_record(msg_id, rec)
         # stream
         d = {}
         if msg_type == 'stream':
             name = content['name']
             s = rec[name] or ''
             d[name] = s + content['data']
 
         elif msg_type == 'pyerr':
             d['pyerr'] = content
         elif msg_type == 'pyin':
             d['pyin'] = content['code']
         elif msg_type in ('display_data', 'pyout'):
             d[msg_type] = content
         elif msg_type == 'status':
             pass
         elif msg_type == 'data_pub':
             self.log.info("ignored data_pub message for %s" % msg_id)
         else:
             self.log.warn("unhandled iopub msg_type: %r", msg_type)
 
         if not d:
             return
 
         try:
             self.db.update_record(msg_id, d)
         except Exception:
             self.log.error("DB Error saving iopub message %r", msg_id, exc_info=True)
 
 
 
     #-------------------------------------------------------------------------
     # Registration requests
     #-------------------------------------------------------------------------
 
     def connection_request(self, client_id, msg):
         """Reply with connection addresses for clients."""
         self.log.info("client::client %r connected", client_id)
         content = dict(status='ok')
         jsonable = {}
         for k,v in self.keytable.iteritems():
             if v not in self.dead_engines:
                 jsonable[str(k)] = v
         content['engines'] = jsonable
         self.session.send(self.query, 'connection_reply', content, parent=msg, ident=client_id)
 
     def register_engine(self, reg, msg):
         """Register a new engine."""
         content = msg['content']
         try:
             uuid = content['uuid']
         except KeyError:
             self.log.error("registration::queue not specified", exc_info=True)
             return
 
         eid = self._next_id
 
         self.log.debug("registration::register_engine(%i, %r)", eid, uuid)
 
         content = dict(id=eid,status='ok',hb_period=self.heartmonitor.period)
         # check if requesting available IDs:
         if cast_bytes(uuid) in self.by_ident:
             try:
                 raise KeyError("uuid %r in use" % uuid)
             except:
                 content = error.wrap_exception()
                 self.log.error("uuid %r in use", uuid, exc_info=True)
         else:
             for h, ec in self.incoming_registrations.iteritems():
                 if uuid == h:
                     try:
                         raise KeyError("heart_id %r in use" % uuid)
                     except:
                         self.log.error("heart_id %r in use", uuid, exc_info=True)
                         content = error.wrap_exception()
                     break
                 elif uuid == ec.uuid:
                     try:
                         raise KeyError("uuid %r in use" % uuid)
                     except:
                         self.log.error("uuid %r in use", uuid, exc_info=True)
                         content = error.wrap_exception()
                     break
 
         msg = self.session.send(self.query, "registration_reply",
                 content=content,
                 ident=reg)
 
         heart = cast_bytes(uuid)
 
         if content['status'] == 'ok':
             if heart in self.heartmonitor.hearts:
                 # already beating
                 self.incoming_registrations[heart] = EngineConnector(id=eid,uuid=uuid)
                 self.finish_registration(heart)
             else:
                 purge = lambda : self._purge_stalled_registration(heart)
                 dc = ioloop.DelayedCallback(purge, self.registration_timeout, self.loop)
                 dc.start()
                 self.incoming_registrations[heart] = EngineConnector(id=eid,uuid=uuid,stallback=dc)
         else:
             self.log.error("registration::registration %i failed: %r", eid, content['evalue'])
         
         return eid
 
     def unregister_engine(self, ident, msg):
         """Unregister an engine that explicitly requested to leave."""
         try:
             eid = msg['content']['id']
         except:
             self.log.error("registration::bad engine id for unregistration: %r", ident, exc_info=True)
             return
         self.log.info("registration::unregister_engine(%r)", eid)
         # print (eid)
         uuid = self.keytable[eid]
         content=dict(id=eid, uuid=uuid)
         self.dead_engines.add(uuid)
         # self.ids.remove(eid)
         # uuid = self.keytable.pop(eid)
         #
         # ec = self.engines.pop(eid)
         # self.hearts.pop(ec.heartbeat)
         # self.by_ident.pop(ec.queue)
         # self.completed.pop(eid)
         handleit = lambda : self._handle_stranded_msgs(eid, uuid)
         dc = ioloop.DelayedCallback(handleit, self.registration_timeout, self.loop)
         dc.start()
         ############## TODO: HANDLE IT ################
         
         self._save_engine_state()
 
         if self.notifier:
             self.session.send(self.notifier, "unregistration_notification", content=content)
 
     def _handle_stranded_msgs(self, eid, uuid):
         """Handle messages known to be on an engine when the engine unregisters.
 
         It is possible that this will fire prematurely - that is, an engine will
         go down after completing a result, and the client will be notified
         that the result failed and later receive the actual result.
         """
 
         outstanding = self.queues[eid]
 
         for msg_id in outstanding:
             self.pending.remove(msg_id)
             self.all_completed.add(msg_id)
             try:
                 raise error.EngineError("Engine %r died while running task %r" % (eid, msg_id))
             except:
                 content = error.wrap_exception()
             # build a fake header:
             header = {}
             header['engine'] = uuid
             header['date'] = datetime.now()
             rec = dict(result_content=content, result_header=header, result_buffers=[])
             rec['completed'] = header['date']
             rec['engine_uuid'] = uuid
             try:
                 self.db.update_record(msg_id, rec)
             except Exception:
                 self.log.error("DB Error handling stranded msg %r", msg_id, exc_info=True)
 
 
     def finish_registration(self, heart):
         """Second half of engine registration, called after our HeartMonitor
         has received a beat from the Engine's Heart."""
         try:
             ec = self.incoming_registrations.pop(heart)
         except KeyError:
             self.log.error("registration::tried to finish nonexistant registration", exc_info=True)
             return
         self.log.info("registration::finished registering engine %i:%s", ec.id, ec.uuid)
         if ec.stallback is not None:
             ec.stallback.stop()
         eid = ec.id
         self.ids.add(eid)
         self.keytable[eid] = ec.uuid
         self.engines[eid] = ec
         self.by_ident[cast_bytes(ec.uuid)] = ec.id
         self.queues[eid] = list()
         self.tasks[eid] = list()
         self.completed[eid] = list()
         self.hearts[heart] = eid
         content = dict(id=eid, uuid=self.engines[eid].uuid)
         if self.notifier:
             self.session.send(self.notifier, "registration_notification", content=content)
         self.log.info("engine::Engine Connected: %i", eid)
         
         self._save_engine_state()
 
     def _purge_stalled_registration(self, heart):
         if heart in self.incoming_registrations:
             ec = self.incoming_registrations.pop(heart)
             self.log.info("registration::purging stalled registration: %i", ec.id)
         else:
             pass
 
     #-------------------------------------------------------------------------
     # Engine State
     #-------------------------------------------------------------------------
 
 
     def _cleanup_engine_state_file(self):
         """cleanup engine state mapping"""
         
         if os.path.exists(self.engine_state_file):
             self.log.debug("cleaning up engine state: %s", self.engine_state_file)
             try:
                 os.remove(self.engine_state_file)
             except IOError:
                 self.log.error("Couldn't cleanup file: %s", self.engine_state_file, exc_info=True)
 
 
     def _save_engine_state(self):
         """save engine mapping to JSON file"""
         if not self.engine_state_file:
             return
         self.log.debug("save engine state to %s" % self.engine_state_file)
         state = {}
         engines = {}
         for eid, ec in self.engines.iteritems():
             if ec.uuid not in self.dead_engines:
                 engines[eid] = ec.uuid
         
         state['engines'] = engines
         
         state['next_id'] = self._idcounter
         
         with open(self.engine_state_file, 'w') as f:
             json.dump(state, f)
 
 
     def _load_engine_state(self):
         """load engine mapping from JSON file"""
         if not os.path.exists(self.engine_state_file):
             return
         
         self.log.info("loading engine state from %s" % self.engine_state_file)
         
         with open(self.engine_state_file) as f:
             state = json.load(f)
         
         save_notifier = self.notifier
         self.notifier = None
         for eid, uuid in state['engines'].iteritems():
             heart = uuid.encode('ascii')
             # start with this heart as current and beating:
             self.heartmonitor.responses.add(heart)
             self.heartmonitor.hearts.add(heart)
             
             self.incoming_registrations[heart] = EngineConnector(id=int(eid), uuid=uuid)
             self.finish_registration(heart)
         
         self.notifier = save_notifier
         
         self._idcounter = state['next_id']
 
     #-------------------------------------------------------------------------
     # Client Requests
     #-------------------------------------------------------------------------
 
     def shutdown_request(self, client_id, msg):
         """handle shutdown request."""
         self.session.send(self.query, 'shutdown_reply', content={'status': 'ok'}, ident=client_id)
         # also notify other clients of shutdown
         self.session.send(self.notifier, 'shutdown_notice', content={'status': 'ok'})
         dc = ioloop.DelayedCallback(lambda : self._shutdown(), 1000, self.loop)
         dc.start()
 
     def _shutdown(self):
         self.log.info("hub::hub shutting down.")
         time.sleep(0.1)
         sys.exit(0)
 
 
     def check_load(self, client_id, msg):
         content = msg['content']
         try:
             targets = content['targets']
             targets = self._validate_targets(targets)
         except:
             content = error.wrap_exception()
             self.session.send(self.query, "hub_error",
                     content=content, ident=client_id)
             return
 
         content = dict(status='ok')
         # loads = {}
         for t in targets:
             content[bytes(t)] = len(self.queues[t])+len(self.tasks[t])
         self.session.send(self.query, "load_reply", content=content, ident=client_id)
 
 
     def queue_status(self, client_id, msg):
         """Return the Queue status of one or more targets.
         if verbose: return the msg_ids
         else: return len of each type.
         keys: queue (pending MUX jobs)
             tasks (pending Task jobs)
             completed (finished jobs from both queues)"""
         content = msg['content']
         targets = content['targets']
         try:
             targets = self._validate_targets(targets)
         except:
             content = error.wrap_exception()
             self.session.send(self.query, "hub_error",
                     content=content, ident=client_id)
             return
         verbose = content.get('verbose', False)
         content = dict(status='ok')
         for t in targets:
             queue = self.queues[t]
             completed = self.completed[t]
             tasks = self.tasks[t]
             if not verbose:
                 queue = len(queue)
                 completed = len(completed)
                 tasks = len(tasks)
             content[str(t)] = {'queue': queue, 'completed': completed , 'tasks': tasks}
         content['unassigned'] = list(self.unassigned) if verbose else len(self.unassigned)
         # print (content)
         self.session.send(self.query, "queue_reply", content=content, ident=client_id)
 
     def purge_results(self, client_id, msg):
         """Purge results from memory. This method is more valuable before we move
         to a DB based message storage mechanism."""
         content = msg['content']
         self.log.info("Dropping records with %s", content)
         msg_ids = content.get('msg_ids', [])
         reply = dict(status='ok')
         if msg_ids == 'all':
             try:
                 self.db.drop_matching_records(dict(completed={'$ne':None}))
             except Exception:
                 reply = error.wrap_exception()
         else:
             pending = filter(lambda m: m in self.pending, msg_ids)
             if pending:
                 try:
                     raise IndexError("msg pending: %r" % pending[0])
                 except:
                     reply = error.wrap_exception()
             else:
                 try:
                     self.db.drop_matching_records(dict(msg_id={'$in':msg_ids}))
                 except Exception:
                     reply = error.wrap_exception()
 
             if reply['status'] == 'ok':
                 eids = content.get('engine_ids', [])
                 for eid in eids:
                     if eid not in self.engines:
                         try:
                             raise IndexError("No such engine: %i" % eid)
                         except:
                             reply = error.wrap_exception()
                         break
                     uid = self.engines[eid].uuid
                     try:
                         self.db.drop_matching_records(dict(engine_uuid=uid, completed={'$ne':None}))
                     except Exception:
                         reply = error.wrap_exception()
                         break
 
         self.session.send(self.query, 'purge_reply', content=reply, ident=client_id)
 
     def resubmit_task(self, client_id, msg):
         """Resubmit one or more tasks."""
         def finish(reply):
             self.session.send(self.query, 'resubmit_reply', content=reply, ident=client_id)
 
         content = msg['content']
         msg_ids = content['msg_ids']
         reply = dict(status='ok')
         try:
             records = self.db.find_records({'msg_id' : {'$in' : msg_ids}}, keys=[
                 'header', 'content', 'buffers'])
         except Exception:
             self.log.error('db::db error finding tasks to resubmit', exc_info=True)
             return finish(error.wrap_exception())
 
         # validate msg_ids
         found_ids = [ rec['msg_id'] for rec in records ]
         pending_ids = [ msg_id for msg_id in found_ids if msg_id in self.pending ]
         if len(records) > len(msg_ids):
             try:
                 raise RuntimeError("DB appears to be in an inconsistent state."
                     "More matching records were found than should exist")
             except Exception:
                 return finish(error.wrap_exception())
         elif len(records) < len(msg_ids):
             missing = [ m for m in msg_ids if m not in found_ids ]
             try:
                 raise KeyError("No such msg(s): %r" % missing)
             except KeyError:
                 return finish(error.wrap_exception())
         elif pending_ids:
             pass
             # no need to raise on resubmit of pending task, now that we
             # resubmit under new ID, but do we want to raise anyway?
             # msg_id = invalid_ids[0]
             # try:
             #     raise ValueError("Task(s) %r appears to be inflight" % )
             # except Exception:
             #     return finish(error.wrap_exception())
 
         # mapping of original IDs to resubmitted IDs
         resubmitted = {}
 
         # send the messages
         for rec in records:
             header = rec['header']
             msg = self.session.msg(header['msg_type'], parent=header)
             msg_id = msg['msg_id']
             msg['content'] = rec['content']
             
             # use the old header, but update msg_id and timestamp
             fresh = msg['header']
             header['msg_id'] = fresh['msg_id']
             header['date'] = fresh['date']
             msg['header'] = header
 
             self.session.send(self.resubmit, msg, buffers=rec['buffers'])
 
             resubmitted[rec['msg_id']] = msg_id
             self.pending.add(msg_id)
             msg['buffers'] = rec['buffers']
             try:
                 self.db.add_record(msg_id, init_record(msg))
             except Exception:
                 self.log.error("db::DB Error updating record: %s", msg_id, exc_info=True)
                 return finish(error.wrap_exception())
 
         finish(dict(status='ok', resubmitted=resubmitted))
         
         # store the new IDs in the Task DB
         for msg_id, resubmit_id in resubmitted.iteritems():
             try:
                 self.db.update_record(msg_id, {'resubmitted' : resubmit_id})
             except Exception:
                 self.log.error("db::DB Error updating record: %s", msg_id, exc_info=True)
 
 
     def _extract_record(self, rec):
         """decompose a TaskRecord dict into subsection of reply for get_result"""
         io_dict = {}
         for key in ('pyin', 'pyout', 'pyerr', 'stdout', 'stderr'):
                 io_dict[key] = rec[key]
         content = { 
             'header': rec['header'],
             'metadata': rec['metadata'],
             'result_metadata': rec['result_metadata'],
             'result_header' : rec['result_header'],
             'result_content': rec['result_content'],
             'received' : rec['received'],
             'io' : io_dict,
         }
         if rec['result_buffers']:
             buffers = map(bytes, rec['result_buffers'])
         else:
             buffers = []
 
         return content, buffers
 
     def get_results(self, client_id, msg):
         """Get the result of 1 or more messages."""
         content = msg['content']
         msg_ids = sorted(set(content['msg_ids']))
         statusonly = content.get('status_only', False)
         pending = []
         completed = []
         content = dict(status='ok')
         content['pending'] = pending
         content['completed'] = completed
         buffers = []
         if not statusonly:
             try:
                 matches = self.db.find_records(dict(msg_id={'$in':msg_ids}))
                 # turn match list into dict, for faster lookup
                 records = {}
                 for rec in matches:
                     records[rec['msg_id']] = rec
             except Exception:
                 content = error.wrap_exception()
                 self.session.send(self.query, "result_reply", content=content,
                                                     parent=msg, ident=client_id)
                 return
         else:
             records = {}
         for msg_id in msg_ids:
             if msg_id in self.pending:
                 pending.append(msg_id)
             elif msg_id in self.all_completed:
                 completed.append(msg_id)
                 if not statusonly:
                     c,bufs = self._extract_record(records[msg_id])
                     content[msg_id] = c
                     buffers.extend(bufs)
             elif msg_id in records:
                 if rec['completed']:
                     completed.append(msg_id)
                     c,bufs = self._extract_record(records[msg_id])
                     content[msg_id] = c
                     buffers.extend(bufs)
                 else:
                     pending.append(msg_id)
             else:
                 try:
                     raise KeyError('No such message: '+msg_id)
                 except:
                     content = error.wrap_exception()
                 break
         self.session.send(self.query, "result_reply", content=content,
                                             parent=msg, ident=client_id,
                                             buffers=buffers)
 
     def get_history(self, client_id, msg):
         """Get a list of all msg_ids in our DB records"""
         try:
             msg_ids = self.db.get_history()
         except Exception as e:
             content = error.wrap_exception()
         else:
             content = dict(status='ok', history=msg_ids)
 
         self.session.send(self.query, "history_reply", content=content,
                                             parent=msg, ident=client_id)
 
     def db_query(self, client_id, msg):
         """Perform a raw query on the task record database."""
         content = msg['content']
         query = content.get('query', {})
         keys = content.get('keys', None)
         buffers = []
         empty = list()
         try:
             records = self.db.find_records(query, keys)
         except Exception as e:
             content = error.wrap_exception()
         else:
             # extract buffers from reply content:
             if keys is not None:
                 buffer_lens = [] if 'buffers' in keys else None
                 result_buffer_lens = [] if 'result_buffers' in keys else None
             else:
                 buffer_lens = None
                 result_buffer_lens = None
 
             for rec in records:
                 # buffers may be None, so double check
                 b = rec.pop('buffers', empty) or empty
                 if buffer_lens is not None:
                     buffer_lens.append(len(b))
                     buffers.extend(b)
                 rb = rec.pop('result_buffers', empty) or empty
                 if result_buffer_lens is not None:
                     result_buffer_lens.append(len(rb))
                     buffers.extend(rb)
             content = dict(status='ok', records=records, buffer_lens=buffer_lens,
                                     result_buffer_lens=result_buffer_lens)
         # self.log.debug (content)
         self.session.send(self.query, "db_reply", content=content,
                                             parent=msg, ident=client_id,
                                             buffers=buffers)
 

IPython/qt/console/qtconsoleapp.py

@@ -1,382 +1,374
 """ A minimal application using the Qt console-style IPython frontend.
 
 This is not a complete console app, as subprocess will not be able to receive
 input, there is no real readline support, among other limitations.
 
 Authors:
 
 * Evan Patterson
 * Min RK
 * Erik Tollerud
 * Fernando Perez
 * Bussonnier Matthias
 * Thomas Kluyver
 * Paul Ivanov
 
 """
 
 #-----------------------------------------------------------------------------
 # Imports
 #-----------------------------------------------------------------------------
 
 # stdlib imports
 import os
 import signal
 import sys
 
 # If run on Windows, install an exception hook which pops up a
 # message box. Pythonw.exe hides the console, so without this
 # the application silently fails to load.
 #
 # We always install this handler, because the expectation is for
 # qtconsole to bring up a GUI even if called from the console.
 # The old handler is called, so the exception is printed as well.
 # If desired, check for pythonw with an additional condition
 # (sys.executable.lower().find('pythonw.exe') >= 0).
 if os.name == 'nt':
     old_excepthook = sys.excepthook
 
     def gui_excepthook(exctype, value, tb):
         try:
             import ctypes, traceback
             MB_ICONERROR = 0x00000010L
             title = u'Error starting IPython QtConsole'
             msg = u''.join(traceback.format_exception(exctype, value, tb))
             ctypes.windll.user32.MessageBoxW(0, msg, title, MB_ICONERROR)
         finally:
             # Also call the old exception hook to let it do
             # its thing too.
             old_excepthook(exctype, value, tb)
 
     sys.excepthook = gui_excepthook
 
 # System library imports
 from IPython.external.qt import QtCore, QtGui
 
 # Local imports
 from IPython.config.application import catch_config_error
 from IPython.core.application import BaseIPythonApplication
 from IPython.qt.console.ipython_widget import IPythonWidget
 from IPython.qt.console.rich_ipython_widget import RichIPythonWidget
 from IPython.qt.console import styles
 from IPython.qt.console.mainwindow import MainWindow
 from IPython.qt.client import QtKernelClient
 from IPython.qt.manager import QtKernelManager
 from IPython.utils.traitlets import (
     Dict, Unicode, CBool, Any
 )
 
 from IPython.consoleapp import (
         IPythonConsoleApp, app_aliases, app_flags, flags, aliases
     )
 
 #-----------------------------------------------------------------------------
 # Network Constants
 #-----------------------------------------------------------------------------
 
 from IPython.utils.localinterfaces import is_local_ip
 
 #-----------------------------------------------------------------------------
 # Globals
 #-----------------------------------------------------------------------------
 
 _examples = """
 ipython qtconsole                      # start the qtconsole
 ipython qtconsole --matplotlib=inline  # start with matplotlib inline plotting mode
 """
 
 #-----------------------------------------------------------------------------
 # Aliases and Flags
 #-----------------------------------------------------------------------------
 
 # start with copy of flags
 flags = dict(flags)
 qt_flags = {
     'plain' : ({'IPythonQtConsoleApp' : {'plain' : True}},
             "Disable rich text support."),
 }
 
 # and app_flags from the Console Mixin
 qt_flags.update(app_flags)
 # add frontend flags to the full set
 flags.update(qt_flags)
 
 # start with copy of front&backend aliases list
 aliases = dict(aliases)
 qt_aliases = dict(
     style = 'IPythonWidget.syntax_style',
     stylesheet = 'IPythonQtConsoleApp.stylesheet',
     colors = 'ZMQInteractiveShell.colors',
 
     editor = 'IPythonWidget.editor',
     paging = 'ConsoleWidget.paging',
 )
 # and app_aliases from the Console Mixin
 qt_aliases.update(app_aliases)
 qt_aliases.update({'gui-completion':'ConsoleWidget.gui_completion'})
 # add frontend aliases to the full set
 aliases.update(qt_aliases)
 
 # get flags&aliases into sets, and remove a couple that
 # shouldn't be scrubbed from backend flags:
 qt_aliases = set(qt_aliases.keys())
 qt_aliases.remove('colors')
 qt_flags = set(qt_flags.keys())
 
 #-----------------------------------------------------------------------------
 # Classes
 #-----------------------------------------------------------------------------
 
 #-----------------------------------------------------------------------------
 # IPythonQtConsole
 #-----------------------------------------------------------------------------
 
 
 class IPythonQtConsoleApp(BaseIPythonApplication, IPythonConsoleApp):
     name = 'ipython-qtconsole'
 
     description = """
         The IPython QtConsole.
         
         This launches a Console-style application using Qt.  It is not a full
         console, in that launched terminal subprocesses will not be able to accept
         input.
         
         The QtConsole supports various extra features beyond the Terminal IPython
         shell, such as inline plotting with matplotlib, via:
         
             ipython qtconsole --matplotlib=inline
         
         as well as saving your session as HTML, and printing the output.
         
     """
     examples = _examples
 
     classes = [IPythonWidget] + IPythonConsoleApp.classes
     flags = Dict(flags)
     aliases = Dict(aliases)
     frontend_flags = Any(qt_flags)
     frontend_aliases = Any(qt_aliases)
     kernel_client_class = QtKernelClient
     kernel_manager_class = QtKernelManager
 
     stylesheet = Unicode('', config=True,
         help="path to a custom CSS stylesheet")
 
     hide_menubar = CBool(False, config=True,
         help="Start the console window with the menu bar hidden.")
 
     maximize = CBool(False, config=True,
         help="Start the console window maximized.")
 
     plain = CBool(False, config=True,
         help="Use a plaintext widget instead of rich text (plain can't print/save).")
 
     def _plain_changed(self, name, old, new):
         kind = 'plain' if new else 'rich'
         self.config.ConsoleWidget.kind = kind
         if new:
             self.widget_factory = IPythonWidget
         else:
             self.widget_factory = RichIPythonWidget
 
     # the factory for creating a widget
     widget_factory = Any(RichIPythonWidget)
 
     def parse_command_line(self, argv=None):
         super(IPythonQtConsoleApp, self).parse_command_line(argv)
         self.build_kernel_argv(argv)
 
 
     def new_frontend_master(self):
         """ Create and return new frontend attached to new kernel, launched on localhost.
         """
         kernel_manager = self.kernel_manager_class(
                                 connection_file=self._new_connection_file(),
                                 parent=self,
                                 autorestart=True,
         )
         # start the kernel
         kwargs = dict()
         kwargs['extra_arguments'] = self.kernel_argv
         kernel_manager.start_kernel(**kwargs)
         kernel_manager.client_factory = self.kernel_client_class
         kernel_client = kernel_manager.client()
         kernel_client.start_channels(shell=True, iopub=True)
         widget = self.widget_factory(config=self.config,
                                    local_kernel=True)
         self.init_colors(widget)
         widget.kernel_manager = kernel_manager
         widget.kernel_client = kernel_client
         widget._existing = False
         widget._may_close = True
         widget._confirm_exit = self.confirm_exit
         return widget
 
     def new_frontend_slave(self, current_widget):
         """Create and return a new frontend attached to an existing kernel.
         
         Parameters
         ----------
         current_widget : IPythonWidget
             The IPythonWidget whose kernel this frontend is to share
         """
         kernel_client = self.kernel_client_class(
                                 connection_file=current_widget.kernel_client.connection_file,
                                 config = self.config,
         )
         kernel_client.load_connection_file()
         kernel_client.start_channels()
         widget = self.widget_factory(config=self.config,
                                 local_kernel=False)
         self.init_colors(widget)
         widget._existing = True
         widget._may_close = False
         widget._confirm_exit = False
         widget.kernel_client = kernel_client
         widget.kernel_manager = current_widget.kernel_manager
         return widget
 
     def init_qt_app(self):
         # separate from qt_elements, because it must run first
         self.app = QtGui.QApplication([])
 
     def init_qt_elements(self):
         # Create the widget.
 
         base_path = os.path.abspath(os.path.dirname(__file__))
         icon_path = os.path.join(base_path, 'resources', 'icon', 'IPythonConsole.svg')
         self.app.icon = QtGui.QIcon(icon_path)
         QtGui.QApplication.setWindowIcon(self.app.icon)
 
         ip = self.ip
         local_kernel = (not self.existing) or is_local_ip(ip)
         self.widget = self.widget_factory(config=self.config,
                                         local_kernel=local_kernel)
         self.init_colors(self.widget)
         self.widget._existing = self.existing
         self.widget._may_close = not self.existing
         self.widget._confirm_exit = self.confirm_exit
 
         self.widget.kernel_manager = self.kernel_manager
         self.widget.kernel_client = self.kernel_client
         self.window = MainWindow(self.app,
                                 confirm_exit=self.confirm_exit,
                                 new_frontend_factory=self.new_frontend_master,
                                 slave_frontend_factory=self.new_frontend_slave,
                                 )
         self.window.log = self.log
         self.window.add_tab_with_frontend(self.widget)
         self.window.init_menu_bar()
 
         # Ignore on OSX, where there is always a menu bar
         if sys.platform != 'darwin' and self.hide_menubar:
             self.window.menuBar().setVisible(False)
 
         self.window.setWindowTitle('IPython')
 
     def init_colors(self, widget):
         """Configure the coloring of the widget"""
         # Note: This will be dramatically simplified when colors
         # are removed from the backend.
 
         # parse the colors arg down to current known labels
-        try:
-            colors = self.config.ZMQInteractiveShell.colors
-        except AttributeError:
-            colors = None
-        try:
-            style = self.config.IPythonWidget.syntax_style
-        except AttributeError:
-            style = None
-        try:
-            sheet = self.config.IPythonWidget.style_sheet
-        except AttributeError:
-            sheet = None
+        cfg = self.config
+        colors = cfg.ZMQInteractiveShell.colors if 'ZMQInteractiveShell.colors' in cfg else None
+        style = cfg.IPythonWidget.syntax_style if 'IPythonWidget.syntax_style' in cfg else None
+        sheet = cfg.IPythonWidget.style_sheet if 'IPythonWidget.style_sheet' in cfg else None
 
         # find the value for colors:
         if colors:
             colors=colors.lower()
             if colors in ('lightbg', 'light'):
                 colors='lightbg'
             elif colors in ('dark', 'linux'):
                 colors='linux'
             else:
                 colors='nocolor'
         elif style:
             if style=='bw':
                 colors='nocolor'
             elif styles.dark_style(style):
                 colors='linux'
             else:
                 colors='lightbg'
         else:
             colors=None
 
         # Configure the style
         if style:
             widget.style_sheet = styles.sheet_from_template(style, colors)
             widget.syntax_style = style
             widget._syntax_style_changed()
             widget._style_sheet_changed()
         elif colors:
             # use a default dark/light/bw style
             widget.set_default_style(colors=colors)
 
         if self.stylesheet:
             # we got an explicit stylesheet
             if os.path.isfile(self.stylesheet):
                 with open(self.stylesheet) as f:
                     sheet = f.read()
             else:
                 raise IOError("Stylesheet %r not found." % self.stylesheet)
         if sheet:
             widget.style_sheet = sheet
             widget._style_sheet_changed()
             
 
     def init_signal(self):
         """allow clean shutdown on sigint"""
         signal.signal(signal.SIGINT, lambda sig, frame: self.exit(-2))
         # need a timer, so that QApplication doesn't block until a real
         # Qt event fires (can require mouse movement)
         # timer trick from http://stackoverflow.com/q/4938723/938949
         timer = QtCore.QTimer()
          # Let the interpreter run each 200 ms:
         timer.timeout.connect(lambda: None)
         timer.start(200)
         # hold onto ref, so the timer doesn't get cleaned up
         self._sigint_timer = timer
 
     @catch_config_error
     def initialize(self, argv=None):
         self.init_qt_app()
         super(IPythonQtConsoleApp, self).initialize(argv)
         IPythonConsoleApp.initialize(self,argv)
         self.init_qt_elements()
         self.init_signal()
 
     def start(self):
 
         # draw the window
         if self.maximize:
             self.window.showMaximized()
         else:
             self.window.show()
         self.window.raise_()
 
         # Start the application main loop.
         self.app.exec_()
 
 #-----------------------------------------------------------------------------
 # Main entry point
 #-----------------------------------------------------------------------------
 
 def main():
     app = IPythonQtConsoleApp()
     app.initialize()
     app.start()
 
 
 if __name__ == '__main__':
     main()