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Backport PR #4118: ZMQ heartbeat channel: catch EINTR exceptions and continue....
Backport PR #4118: ZMQ heartbeat channel: catch EINTR exceptions and continue. The zmq heartbeat channel exits when it encounters an "Interrupted system call", thereby causing the qtconsole to report that it is not responding, despite the console working perfectly fine. Observed in a large Qt application embedding the ipython qtconsole in KDE desktop. Fixes #2310 Inspired by #501

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application.py
578 lines | 20.5 KiB | text/x-python | PythonLexer
# encoding: utf-8
"""
A base class for a configurable application.
Authors:
* Brian Granger
* 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 logging
import os
import re
import sys
from copy import deepcopy
from collections import defaultdict
from IPython.external.decorator import decorator
from IPython.config.configurable import SingletonConfigurable
from IPython.config.loader import (
KVArgParseConfigLoader, PyFileConfigLoader, Config, ArgumentError, ConfigFileNotFound,
)
from IPython.utils.traitlets import (
Unicode, List, Enum, Dict, Instance, TraitError
)
from IPython.utils.importstring import import_item
from IPython.utils.text import indent, wrap_paragraphs, dedent
#-----------------------------------------------------------------------------
# function for re-wrapping a helpstring
#-----------------------------------------------------------------------------
#-----------------------------------------------------------------------------
# Descriptions for the various sections
#-----------------------------------------------------------------------------
# merge flags&aliases into options
option_description = """
Arguments that take values are actually convenience aliases to full
Configurables, whose aliases are listed on the help line. For more information
on full configurables, see '--help-all'.
""".strip() # trim newlines of front and back
keyvalue_description = """
Parameters are set from command-line arguments of the form:
`--Class.trait=value`.
This line is evaluated in Python, so simple expressions are allowed, e.g.::
`--C.a='range(3)'` For setting C.a=[0,1,2].
""".strip() # trim newlines of front and back
# sys.argv can be missing, for example when python is embedded. See the docs
# for details: http://docs.python.org/2/c-api/intro.html#embedding-python
if not hasattr(sys, "argv"):
sys.argv = [""]
subcommand_description = """
Subcommands are launched as `{app} cmd [args]`. For information on using
subcommand 'cmd', do: `{app} cmd -h`.
""".strip().format(app=os.path.basename(sys.argv[0]))
# get running program name
#-----------------------------------------------------------------------------
# Application class
#-----------------------------------------------------------------------------
@decorator
def catch_config_error(method, app, *args, **kwargs):
"""Method decorator for catching invalid config (Trait/ArgumentErrors) during init.
On a TraitError (generally caused by bad config), this will print the trait's
message, and exit the app.
For use on init methods, to prevent invoking excepthook on invalid input.
"""
try:
return method(app, *args, **kwargs)
except (TraitError, ArgumentError) as e:
app.print_help()
app.log.fatal("Bad config encountered during initialization:")
app.log.fatal(str(e))
app.log.debug("Config at the time: %s", app.config)
app.exit(1)
class ApplicationError(Exception):
pass
class LevelFormatter(logging.Formatter):
"""Formatter with additional `highlevel` record
This field is empty if log level is less than highlevel_limit,
otherwise it is formatted with self.highlevel_format.
Useful for adding 'WARNING' to warning messages,
without adding 'INFO' to info, etc.
"""
highlevel_limit = logging.WARN
highlevel_format = " %(levelname)s |"
def format(self, record):
if record.levelno >= self.highlevel_limit:
record.highlevel = self.highlevel_format % record.__dict__
else:
record.highlevel = ""
if sys.version_info[:2] > (2,6):
return super(LevelFormatter, self).format(record)
else:
return logging.Formatter.format(self, record)
class Application(SingletonConfigurable):
"""A singleton application with full configuration support."""
# The name of the application, will usually match the name of the command
# line application
name = Unicode(u'application')
# The description of the application that is printed at the beginning
# of the help.
description = Unicode(u'This is an application.')
# default section descriptions
option_description = Unicode(option_description)
keyvalue_description = Unicode(keyvalue_description)
subcommand_description = Unicode(subcommand_description)
# The usage and example string that goes at the end of the help string.
examples = Unicode()
# A sequence of Configurable subclasses whose config=True attributes will
# be exposed at the command line.
classes = List([])
# The version string of this application.
version = Unicode(u'0.0')
# The log level for the application
log_level = Enum((0,10,20,30,40,50,'DEBUG','INFO','WARN','ERROR','CRITICAL'),
default_value=logging.WARN,
config=True,
help="Set the log level by value or name.")
def _log_level_changed(self, name, old, new):
"""Adjust the log level when log_level is set."""
if isinstance(new, basestring):
new = getattr(logging, new)
self.log_level = new
self.log.setLevel(new)
log_datefmt = Unicode("%Y-%m-%d %H:%M:%S", config=True,
help="The date format used by logging formatters for %(asctime)s"
)
def _log_datefmt_changed(self, name, old, new):
self._log_format_changed()
log_format = Unicode("[%(name)s]%(highlevel)s %(message)s", config=True,
help="The Logging format template",
)
def _log_format_changed(self, name, old, new):
"""Change the log formatter when log_format is set."""
_log_handler = self.log.handlers[0]
_log_formatter = LevelFormatter(new, datefmt=self.log_datefmt)
_log_handler.setFormatter(_log_formatter)
log = Instance(logging.Logger)
def _log_default(self):
"""Start logging for this application.
The default is to log to stderr using a StreamHandler, if no default
handler already exists. The log level starts at logging.WARN, but this
can be adjusted by setting the ``log_level`` attribute.
"""
log = logging.getLogger(self.__class__.__name__)
log.setLevel(self.log_level)
log.propagate = False
_log = log # copied from Logger.hasHandlers() (new in Python 3.2)
while _log:
if _log.handlers:
return log
if not _log.propagate:
break
else:
_log = _log.parent
if sys.executable.endswith('pythonw.exe'):
# this should really go to a file, but file-logging is only
# hooked up in parallel applications
_log_handler = logging.StreamHandler(open(os.devnull, 'w'))
else:
_log_handler = logging.StreamHandler()
_log_formatter = LevelFormatter(self.log_format, datefmt=self.log_datefmt)
_log_handler.setFormatter(_log_formatter)
log.addHandler(_log_handler)
return log
# the alias map for configurables
aliases = Dict({'log-level' : 'Application.log_level'})
# flags for loading Configurables or store_const style flags
# flags are loaded from this dict by '--key' flags
# this must be a dict of two-tuples, the first element being the Config/dict
# and the second being the help string for the flag
flags = Dict()
def _flags_changed(self, name, old, new):
"""ensure flags dict is valid"""
for key,value in new.iteritems():
assert len(value) == 2, "Bad flag: %r:%s"%(key,value)
assert isinstance(value[0], (dict, Config)), "Bad flag: %r:%s"%(key,value)
assert isinstance(value[1], basestring), "Bad flag: %r:%s"%(key,value)
# subcommands for launching other applications
# if this is not empty, this will be a parent Application
# this must be a dict of two-tuples,
# the first element being the application class/import string
# and the second being the help string for the subcommand
subcommands = Dict()
# parse_command_line will initialize a subapp, if requested
subapp = Instance('IPython.config.application.Application', allow_none=True)
# extra command-line arguments that don't set config values
extra_args = List(Unicode)
def __init__(self, **kwargs):
SingletonConfigurable.__init__(self, **kwargs)
# Ensure my class is in self.classes, so my attributes appear in command line
# options and config files.
if self.__class__ not in self.classes:
self.classes.insert(0, self.__class__)
def _config_changed(self, name, old, new):
SingletonConfigurable._config_changed(self, name, old, new)
self.log.debug('Config changed:')
self.log.debug(repr(new))
@catch_config_error
def initialize(self, argv=None):
"""Do the basic steps to configure me.
Override in subclasses.
"""
self.parse_command_line(argv)
def start(self):
"""Start the app mainloop.
Override in subclasses.
"""
if self.subapp is not None:
return self.subapp.start()
def print_alias_help(self):
"""Print the alias part of the help."""
if not self.aliases:
return
lines = []
classdict = {}
for cls in self.classes:
# include all parents (up to, but excluding Configurable) in available names
for c in cls.mro()[:-3]:
classdict[c.__name__] = c
for alias, longname in self.aliases.iteritems():
classname, traitname = longname.split('.',1)
cls = classdict[classname]
trait = cls.class_traits(config=True)[traitname]
help = cls.class_get_trait_help(trait).splitlines()
# reformat first line
help[0] = help[0].replace(longname, alias) + ' (%s)'%longname
if len(alias) == 1:
help[0] = help[0].replace('--%s='%alias, '-%s '%alias)
lines.extend(help)
# lines.append('')
print os.linesep.join(lines)
def print_flag_help(self):
"""Print the flag part of the help."""
if not self.flags:
return
lines = []
for m, (cfg,help) in self.flags.iteritems():
prefix = '--' if len(m) > 1 else '-'
lines.append(prefix+m)
lines.append(indent(dedent(help.strip())))
# lines.append('')
print os.linesep.join(lines)
def print_options(self):
if not self.flags and not self.aliases:
return
lines = ['Options']
lines.append('-'*len(lines[0]))
lines.append('')
for p in wrap_paragraphs(self.option_description):
lines.append(p)
lines.append('')
print os.linesep.join(lines)
self.print_flag_help()
self.print_alias_help()
print
def print_subcommands(self):
"""Print the subcommand part of the help."""
if not self.subcommands:
return
lines = ["Subcommands"]
lines.append('-'*len(lines[0]))
lines.append('')
for p in wrap_paragraphs(self.subcommand_description):
lines.append(p)
lines.append('')
for subc, (cls, help) in self.subcommands.iteritems():
lines.append(subc)
if help:
lines.append(indent(dedent(help.strip())))
lines.append('')
print os.linesep.join(lines)
def print_help(self, classes=False):
"""Print the help for each Configurable class in self.classes.
If classes=False (the default), only flags and aliases are printed.
"""
self.print_description()
self.print_subcommands()
self.print_options()
if classes:
if self.classes:
print "Class parameters"
print "----------------"
print
for p in wrap_paragraphs(self.keyvalue_description):
print p
print
for cls in self.classes:
cls.class_print_help()
print
else:
print "To see all available configurables, use `--help-all`"
print
self.print_examples()
def print_description(self):
"""Print the application description."""
for p in wrap_paragraphs(self.description):
print p
print
def print_examples(self):
"""Print usage and examples.
This usage string goes at the end of the command line help string
and should contain examples of the application's usage.
"""
if self.examples:
print "Examples"
print "--------"
print
print indent(dedent(self.examples.strip()))
print
def print_version(self):
"""Print the version string."""
print self.version
def update_config(self, config):
"""Fire the traits events when the config is updated."""
# Save a copy of the current config.
newconfig = deepcopy(self.config)
# Merge the new config into the current one.
newconfig.merge(config)
# Save the combined config as self.config, which triggers the traits
# events.
self.config = newconfig
@catch_config_error
def initialize_subcommand(self, subc, argv=None):
"""Initialize a subcommand with argv."""
subapp,help = self.subcommands.get(subc)
if isinstance(subapp, basestring):
subapp = import_item(subapp)
# clear existing instances
self.__class__.clear_instance()
# instantiate
self.subapp = subapp.instance(config=self.config)
# and initialize subapp
self.subapp.initialize(argv)
def flatten_flags(self):
"""flatten flags and aliases, so cl-args override as expected.
This prevents issues such as an alias pointing to InteractiveShell,
but a config file setting the same trait in TerminalInteraciveShell
getting inappropriate priority over the command-line arg.
Only aliases with exactly one descendent in the class list
will be promoted.
"""
# build a tree of classes in our list that inherit from a particular
# it will be a dict by parent classname of classes in our list
# that are descendents
mro_tree = defaultdict(list)
for cls in self.classes:
clsname = cls.__name__
for parent in cls.mro()[1:-3]:
# exclude cls itself and Configurable,HasTraits,object
mro_tree[parent.__name__].append(clsname)
# flatten aliases, which have the form:
# { 'alias' : 'Class.trait' }
aliases = {}
for alias, cls_trait in self.aliases.iteritems():
cls,trait = cls_trait.split('.',1)
children = mro_tree[cls]
if len(children) == 1:
# exactly one descendent, promote alias
cls = children[0]
aliases[alias] = '.'.join([cls,trait])
# flatten flags, which are of the form:
# { 'key' : ({'Cls' : {'trait' : value}}, 'help')}
flags = {}
for key, (flagdict, help) in self.flags.iteritems():
newflag = {}
for cls, subdict in flagdict.iteritems():
children = mro_tree[cls]
# exactly one descendent, promote flag section
if len(children) == 1:
cls = children[0]
newflag[cls] = subdict
flags[key] = (newflag, help)
return flags, aliases
@catch_config_error
def parse_command_line(self, argv=None):
"""Parse the command line arguments."""
argv = sys.argv[1:] if argv is None else argv
if argv and argv[0] == 'help':
# turn `ipython help notebook` into `ipython notebook -h`
argv = argv[1:] + ['-h']
if self.subcommands and len(argv) > 0:
# we have subcommands, and one may have been specified
subc, subargv = argv[0], argv[1:]
if re.match(r'^\w(\-?\w)*$', subc) and subc in self.subcommands:
# it's a subcommand, and *not* a flag or class parameter
return self.initialize_subcommand(subc, subargv)
# Arguments after a '--' argument are for the script IPython may be
# about to run, not IPython iteslf. For arguments parsed here (help and
# version), we want to only search the arguments up to the first
# occurrence of '--', which we're calling interpreted_argv.
try:
interpreted_argv = argv[:argv.index('--')]
except ValueError:
interpreted_argv = argv
if any(x in interpreted_argv for x in ('-h', '--help-all', '--help')):
self.print_help('--help-all' in interpreted_argv)
self.exit(0)
if '--version' in interpreted_argv or '-V' in interpreted_argv:
self.print_version()
self.exit(0)
# flatten flags&aliases, so cl-args get appropriate priority:
flags,aliases = self.flatten_flags()
loader = KVArgParseConfigLoader(argv=argv, aliases=aliases,
flags=flags)
config = loader.load_config()
self.update_config(config)
# store unparsed args in extra_args
self.extra_args = loader.extra_args
@catch_config_error
def load_config_file(self, filename, path=None):
"""Load a .py based config file by filename and path."""
loader = PyFileConfigLoader(filename, path=path)
try:
config = loader.load_config()
except ConfigFileNotFound:
# problem finding the file, raise
raise
except Exception:
# try to get the full filename, but it will be empty in the
# unlikely event that the error raised before filefind finished
filename = loader.full_filename or filename
# problem while running the file
self.log.error("Exception while loading config file %s",
filename, exc_info=True)
else:
self.log.debug("Loaded config file: %s", loader.full_filename)
self.update_config(config)
def generate_config_file(self):
"""generate default config file from Configurables"""
lines = ["# Configuration file for %s."%self.name]
lines.append('')
lines.append('c = get_config()')
lines.append('')
for cls in self.classes:
lines.append(cls.class_config_section())
return '\n'.join(lines)
def exit(self, exit_status=0):
self.log.debug("Exiting application: %s" % self.name)
sys.exit(exit_status)
@classmethod
def launch_instance(cls, argv=None, **kwargs):
"""Launch a global instance of this Application
If a global instance already exists, this reinitializes and starts it
"""
app = cls.instance(**kwargs)
app.initialize(argv)
app.start()
#-----------------------------------------------------------------------------
# utility functions, for convenience
#-----------------------------------------------------------------------------
def boolean_flag(name, configurable, set_help='', unset_help=''):
"""Helper for building basic --trait, --no-trait flags.
Parameters
----------
name : str
The name of the flag.
configurable : str
The 'Class.trait' string of the trait to be set/unset with the flag
set_help : unicode
help string for --name flag
unset_help : unicode
help string for --no-name flag
Returns
-------
cfg : dict
A dict with two keys: 'name', and 'no-name', for setting and unsetting
the trait, respectively.
"""
# default helpstrings
set_help = set_help or "set %s=True"%configurable
unset_help = unset_help or "set %s=False"%configurable
cls,trait = configurable.split('.')
setter = {cls : {trait : True}}
unsetter = {cls : {trait : False}}
return {name : (setter, set_help), 'no-'+name : (unsetter, unset_help)}