flush messages printed during startup

Prevents print statements during init methods from being associated with the first execution.

closes  #1022

IPython/lib/pylabtools.py

@@ -1,322 +1,325
 # -*- coding: utf-8 -*-
 """Pylab (matplotlib) support utilities.
 
 Authors
 -------
 
 * Fernando Perez.
 * Brian Granger
 """
 
 #-----------------------------------------------------------------------------
 #  Copyright (C) 2009  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 sys
 from io import BytesIO
 
 from IPython.utils.decorators import flag_calls
 
 # If user specifies a GUI, that dictates the backend, otherwise we read the
 # user's mpl default from the mpl rc structure
 backends = {'tk': 'TkAgg',
             'gtk': 'GTKAgg',
             'wx': 'WXAgg',
             'qt': 'Qt4Agg', # qt3 not supported
             'qt4': 'Qt4Agg',
             'osx': 'MacOSX',
             'inline' : 'module://IPython.zmq.pylab.backend_inline'}
 
 # We also need a reverse backends2guis mapping that will properly choose which
 # GUI support to activate based on the desired matplotlib backend.  For the
 # most part it's just a reverse of the above dict, but we also need to add a
 # few others that map to the same GUI manually:
 backend2gui = dict(zip(backends.values(), backends.keys()))
 # In the reverse mapping, there are a few extra valid matplotlib backends that
 # map to the same GUI support
 backend2gui['GTK'] = backend2gui['GTKCairo'] = 'gtk'
 backend2gui['WX'] = 'wx'
 backend2gui['CocoaAgg'] = 'osx'
 
 #-----------------------------------------------------------------------------
 # Matplotlib utilities
 #-----------------------------------------------------------------------------
 
 
 def getfigs(*fig_nums):
     """Get a list of matplotlib figures by figure numbers.
 
     If no arguments are given, all available figures are returned.  If the
     argument list contains references to invalid figures, a warning is printed
     but the function continues pasting further figures.
 
     Parameters
     ----------
     figs : tuple
         A tuple of ints giving the figure numbers of the figures to return.
     """
     from matplotlib._pylab_helpers import Gcf
     if not fig_nums:
         fig_managers = Gcf.get_all_fig_managers()
         return [fm.canvas.figure for fm in fig_managers]
     else:
         figs = []
         for num in fig_nums:
             f = Gcf.figs.get(num)
             if f is None:
                 print('Warning: figure %s not available.' % num)
             else:
                 figs.append(f.canvas.figure)
         return figs
 
 
 def figsize(sizex, sizey):
     """Set the default figure size to be [sizex, sizey].
 
     This is just an easy to remember, convenience wrapper that sets::
 
       matplotlib.rcParams['figure.figsize'] = [sizex, sizey]
     """
     import matplotlib
     matplotlib.rcParams['figure.figsize'] = [sizex, sizey]
 
 
 def print_figure(fig, fmt='png'):
     """Convert a figure to svg or png for inline display."""
     # When there's an empty figure, we shouldn't return anything, otherwise we
     # get big blank areas in the qt console.
     if not fig.axes:
         return
 
     fc = fig.get_facecolor()
     ec = fig.get_edgecolor()
     fig.set_facecolor('white')
     fig.set_edgecolor('white')
     try:
         bytes_io = BytesIO()
         fig.canvas.print_figure(bytes_io, format=fmt, bbox_inches='tight')
         data = bytes_io.getvalue()
     finally:
         fig.set_facecolor(fc)
         fig.set_edgecolor(ec)
     return data
 
 
 # We need a little factory function here to create the closure where
 # safe_execfile can live.
 def mpl_runner(safe_execfile):
     """Factory to return a matplotlib-enabled runner for %run.
 
     Parameters
     ----------
     safe_execfile : function
       This must be a function with the same interface as the
       :meth:`safe_execfile` method of IPython.
 
     Returns
     -------
     A function suitable for use as the ``runner`` argument of the %run magic
     function.
     """
     
     def mpl_execfile(fname,*where,**kw):
         """matplotlib-aware wrapper around safe_execfile.
 
         Its interface is identical to that of the :func:`execfile` builtin.
 
         This is ultimately a call to execfile(), but wrapped in safeties to
         properly handle interactive rendering."""
 
         import matplotlib
         import matplotlib.pylab as pylab
 
         #print '*** Matplotlib runner ***' # dbg
         # turn off rendering until end of script
         is_interactive = matplotlib.rcParams['interactive']
         matplotlib.interactive(False)
         safe_execfile(fname,*where,**kw)
         matplotlib.interactive(is_interactive)
         # make rendering call now, if the user tried to do it
         if pylab.draw_if_interactive.called:
             pylab.draw()
             pylab.draw_if_interactive.called = False
 
     return mpl_execfile
 
 
 def select_figure_format(shell, fmt):
     """Select figure format for inline backend, either 'png' or 'svg'.
 
     Using this method ensures only one figure format is active at a time.
     """
     from matplotlib.figure import Figure
     from IPython.zmq.pylab import backend_inline
 
     svg_formatter = shell.display_formatter.formatters['image/svg+xml']
     png_formatter = shell.display_formatter.formatters['image/png']
 
     if fmt=='png':
         svg_formatter.type_printers.pop(Figure, None)
         png_formatter.for_type(Figure, lambda fig: print_figure(fig, 'png'))
     elif fmt=='svg':
         png_formatter.type_printers.pop(Figure, None)
         svg_formatter.for_type(Figure, lambda fig: print_figure(fig, 'svg'))
     else:
         raise ValueError("supported formats are: 'png', 'svg', not %r"%fmt)
 
     # set the format to be used in the backend()
     backend_inline._figure_format = fmt
 
 #-----------------------------------------------------------------------------
 # Code for initializing matplotlib and importing pylab
 #-----------------------------------------------------------------------------
 
 
 def find_gui_and_backend(gui=None):
     """Given a gui string return the gui and mpl backend.
 
     Parameters
     ----------
     gui : str
         Can be one of ('tk','gtk','wx','qt','qt4','inline').
 
     Returns
     -------
     A tuple of (gui, backend) where backend is one of ('TkAgg','GTKAgg',
     'WXAgg','Qt4Agg','module://IPython.zmq.pylab.backend_inline').
     """
 
     import matplotlib
 
     if gui and gui != 'auto':
         # select backend based on requested gui
         backend = backends[gui]
     else:
         backend = matplotlib.rcParams['backend']
         # In this case, we need to find what the appropriate gui selection call
         # should be for IPython, so we can activate inputhook accordingly
         gui = backend2gui.get(backend, None)
     return gui, backend
 
 
 def activate_matplotlib(backend):
     """Activate the given backend and set interactive to True."""
 
     import matplotlib
     if backend.startswith('module://'):
         # Work around bug in matplotlib: matplotlib.use converts the
         # backend_id to lowercase even if a module name is specified!
         matplotlib.rcParams['backend'] = backend
     else:
         matplotlib.use(backend)
     matplotlib.interactive(True)
 
     # This must be imported last in the matplotlib series, after
     # backend/interactivity choices have been made
     import matplotlib.pylab as pylab
 
     # XXX For now leave this commented out, but depending on discussions with
     # mpl-dev, we may be able to allow interactive switching...
     #import matplotlib.pyplot
     #matplotlib.pyplot.switch_backend(backend)
 
     pylab.show._needmain = False
     # We need to detect at runtime whether show() is called by the user.
     # For this, we wrap it into a decorator which adds a 'called' flag.
     pylab.draw_if_interactive = flag_calls(pylab.draw_if_interactive)
 
 def import_pylab(user_ns, backend, import_all=True, shell=None):
     """Import the standard pylab symbols into user_ns."""
 
     # Import numpy as np/pyplot as plt are conventions we're trying to
     # somewhat standardize on.  Making them available to users by default
     # will greatly help this.
     s = ("import numpy\n"
           "import matplotlib\n"
           "from matplotlib import pylab, mlab, pyplot\n"
           "np = numpy\n"
           "plt = pyplot\n"
           )
     exec s in user_ns
 
     if shell is not None:
         exec s in shell.user_ns_hidden
         # If using our svg payload backend, register the post-execution
         # function that will pick up the results for display.  This can only be
         # done with access to the real shell object.
         #
         from IPython.zmq.pylab.backend_inline import InlineBackend
 
         cfg = InlineBackend.instance(config=shell.config)
         cfg.shell = shell
         if cfg not in shell.configurables:
             shell.configurables.append(cfg)
 
         if backend == backends['inline']:
             from IPython.zmq.pylab.backend_inline import flush_figures
             from matplotlib import pyplot
             shell.register_post_execute(flush_figures)
             # load inline_rc
             pyplot.rcParams.update(cfg.rc)
             
             # Add 'figsize' to pyplot and to the user's namespace
             user_ns['figsize'] = pyplot.figsize = figsize
             shell.user_ns_hidden['figsize'] = figsize
         
         # Setup the default figure format
         fmt = cfg.figure_format
         select_figure_format(shell, fmt)
 
         # The old pastefig function has been replaced by display
         from IPython.core.display import display
         # Add display and display_png to the user's namespace
         user_ns['display'] = display
         shell.user_ns_hidden['display'] = display
         user_ns['getfigs'] = getfigs
         shell.user_ns_hidden['getfigs'] = getfigs
 
     if import_all:
         s = ("from matplotlib.pylab import *\n"
              "from numpy import *\n")
         exec s in user_ns
         if shell is not None:
             exec s in shell.user_ns_hidden
 
 
 def pylab_activate(user_ns, gui=None, import_all=True, shell=None):
     """Activate pylab mode in the user's namespace.
 
     Loads and initializes numpy, matplotlib and friends for interactive use.
 
     Parameters
     ----------
     user_ns : dict
       Namespace where the imports will occur.
 
     gui : optional, string
       A valid gui name following the conventions of the %gui magic.
 
     import_all : optional, boolean
       If true, an 'import *' is done from numpy and pylab.
 
     Returns
     -------
     The actual gui used (if not given as input, it was obtained from matplotlib
     itself, and will be needed next to configure IPython's gui integration.
     """
     gui, backend = find_gui_and_backend(gui)
     activate_matplotlib(backend)
     import_pylab(user_ns, backend, import_all, shell)
 
     print """
 Welcome to pylab, a matplotlib-based Python environment [backend: %s].
 For more information, type 'help(pylab)'.""" % backend
+    # flush stdout, just to be safe
+    sys.stdout.flush()
     
     return gui
 

IPython/zmq/kernelapp.py

@@ -1,299 +1,303
 """An Application for launching a kernel
 
 Authors
 -------
 * MinRK
 """
 #-----------------------------------------------------------------------------
 #  Copyright (C) 2011  The IPython Development Team
 #
 #  Distributed under the terms of the BSD License.  The full license is in
 #  the file COPYING.txt, distributed as part of this software.
 #-----------------------------------------------------------------------------
 
 #-----------------------------------------------------------------------------
 # Imports
 #-----------------------------------------------------------------------------
 
 # Standard library imports.
 import json
 import os
 import sys
 
 # System library imports.
 import zmq
 
 # IPython imports.
 from IPython.core.ultratb import FormattedTB
 from IPython.core.application import (
     BaseIPythonApplication, base_flags, base_aliases, catch_config_error
 )
 from IPython.utils import io
 from IPython.utils.localinterfaces import LOCALHOST
 from IPython.utils.path import filefind
 from IPython.utils.py3compat import str_to_bytes
 from IPython.utils.traitlets import (Any, Instance, Dict, Unicode, Integer, Bool,
                                         DottedObjectName)
 from IPython.utils.importstring import import_item
 # local imports
 from IPython.zmq.entry_point import write_connection_file
 from IPython.zmq.heartbeat import Heartbeat
 from IPython.zmq.parentpoller import ParentPollerUnix, ParentPollerWindows
 from IPython.zmq.session import (
     Session, session_flags, session_aliases, default_secure,
 )
 
 
 #-----------------------------------------------------------------------------
 # Flags and Aliases
 #-----------------------------------------------------------------------------
 
 kernel_aliases = dict(base_aliases)
 kernel_aliases.update({
     'ip' : 'KernelApp.ip',
     'hb' : 'KernelApp.hb_port',
     'shell' : 'KernelApp.shell_port',
     'iopub' : 'KernelApp.iopub_port',
     'stdin' : 'KernelApp.stdin_port',
     'f' : 'KernelApp.connection_file',
     'parent': 'KernelApp.parent',
 })
 if sys.platform.startswith('win'):
     kernel_aliases['interrupt'] = 'KernelApp.interrupt'
 
 kernel_flags = dict(base_flags)
 kernel_flags.update({
     'no-stdout' : (
             {'KernelApp' : {'no_stdout' : True}},
             "redirect stdout to the null device"),
     'no-stderr' : (
             {'KernelApp' : {'no_stderr' : True}},
             "redirect stderr to the null device"),
 })
 
 # inherit flags&aliases for Sessions
 kernel_aliases.update(session_aliases)
 kernel_flags.update(session_flags)
 
 
 
 #-----------------------------------------------------------------------------
 # Application class for starting a Kernel
 #-----------------------------------------------------------------------------
 
 class KernelApp(BaseIPythonApplication):
     name='pykernel'
     aliases = Dict(kernel_aliases)
     flags = Dict(kernel_flags)
     classes = [Session]
     # the kernel class, as an importstring
     kernel_class = DottedObjectName('IPython.zmq.pykernel.Kernel')
     kernel = Any()
     poller = Any() # don't restrict this even though current pollers are all Threads
     heartbeat = Instance(Heartbeat)
     session = Instance('IPython.zmq.session.Session')
     ports = Dict()
     
     # inherit config file name from parent:
     parent_appname = Unicode(config=True)
     def _parent_appname_changed(self, name, old, new):
         if self.config_file_specified:
             # it was manually specified, ignore
             return
         self.config_file_name = new.replace('-','_') + u'_config.py'
         # don't let this count as specifying the config file
         self.config_file_specified = False
         
     # connection info:
     ip = Unicode(LOCALHOST, config=True,
         help="Set the IP or interface on which the kernel will listen.")
     hb_port = Integer(0, config=True, help="set the heartbeat port [default: random]")
     shell_port = Integer(0, config=True, help="set the shell (XREP) port [default: random]")
     iopub_port = Integer(0, config=True, help="set the iopub (PUB) port [default: random]")
     stdin_port = Integer(0, config=True, help="set the stdin (XREQ) port [default: random]")
     connection_file = Unicode('', config=True, 
     help="""JSON file in which to store connection info [default: kernel-<pid>.json]
     
     This file will contain the IP, ports, and authentication key needed to connect
     clients to this kernel. By default, this file will be created in the security-dir
     of the current profile, but can be specified by absolute path.
     """)
 
     # streams, etc.
     no_stdout = Bool(False, config=True, help="redirect stdout to the null device")
     no_stderr = Bool(False, config=True, help="redirect stderr to the null device")
     outstream_class = DottedObjectName('IPython.zmq.iostream.OutStream',
         config=True, help="The importstring for the OutStream factory")
     displayhook_class = DottedObjectName('IPython.zmq.displayhook.ZMQDisplayHook',
         config=True, help="The importstring for the DisplayHook factory")
 
     # polling
     parent = Integer(0, config=True,
         help="""kill this process if its parent dies.  On Windows, the argument
         specifies the HANDLE of the parent process, otherwise it is simply boolean.
         """)
     interrupt = Integer(0, config=True,
         help="""ONLY USED ON WINDOWS
         Interrupt this process when the parent is signalled.
         """)
 
     def init_crash_handler(self):
         # Install minimal exception handling
         sys.excepthook = FormattedTB(mode='Verbose', color_scheme='NoColor',
                                      ostream=sys.__stdout__)
 
     def init_poller(self):
         if sys.platform == 'win32':
             if self.interrupt or self.parent:
                 self.poller = ParentPollerWindows(self.interrupt, self.parent)
         elif self.parent:
             self.poller = ParentPollerUnix()
 
     def _bind_socket(self, s, port):
         iface = 'tcp://%s' % self.ip
         if port <= 0:
             port = s.bind_to_random_port(iface)
         else:
             s.bind(iface + ':%i'%port)
         return port
 
     def load_connection_file(self):
         """load ip/port/hmac config from JSON connection file"""
         try:
             fname = filefind(self.connection_file, ['.', self.profile_dir.security_dir])
         except IOError:
             self.log.debug("Connection file not found: %s", self.connection_file)
             return
         self.log.debug(u"Loading connection file %s", fname)
         with open(fname) as f:
             s = f.read()
         cfg = json.loads(s)
         if self.ip == LOCALHOST and 'ip' in cfg:
             # not overridden by config or cl_args
             self.ip = cfg['ip']
         for channel in ('hb', 'shell', 'iopub', 'stdin'):
             name = channel + '_port'
             if getattr(self, name) == 0 and name in cfg:
                 # not overridden by config or cl_args
                 setattr(self, name, cfg[name])
         if 'key' in cfg:
             self.config.Session.key = str_to_bytes(cfg['key'])
     
     def write_connection_file(self):
         """write connection info to JSON file"""
         if os.path.basename(self.connection_file) == self.connection_file:
             cf = os.path.join(self.profile_dir.security_dir, self.connection_file)
         else:
             cf = self.connection_file
         write_connection_file(cf, ip=self.ip, key=self.session.key,
         shell_port=self.shell_port, stdin_port=self.stdin_port, hb_port=self.hb_port,
         iopub_port=self.iopub_port)
     
     def init_connection_file(self):
         if not self.connection_file:
             self.connection_file = "kernel-%s.json"%os.getpid()
         try:
             self.load_connection_file()
         except Exception:
             self.log.error("Failed to load connection file: %r", self.connection_file, exc_info=True)
             self.exit(1)
     
     def init_sockets(self):
         # Create a context, a session, and the kernel sockets.
         self.log.info("Starting the kernel at pid: %i", os.getpid())
         context = zmq.Context.instance()
         # Uncomment this to try closing the context.
         # atexit.register(context.term)
 
         self.shell_socket = context.socket(zmq.ROUTER)
         self.shell_port = self._bind_socket(self.shell_socket, self.shell_port)
         self.log.debug("shell ROUTER Channel on port: %i"%self.shell_port)
 
         self.iopub_socket = context.socket(zmq.PUB)
         self.iopub_port = self._bind_socket(self.iopub_socket, self.iopub_port)
         self.log.debug("iopub PUB Channel on port: %i"%self.iopub_port)
 
         self.stdin_socket = context.socket(zmq.ROUTER)
         self.stdin_port = self._bind_socket(self.stdin_socket, self.stdin_port)
         self.log.debug("stdin ROUTER Channel on port: %i"%self.stdin_port)
 
         self.heartbeat = Heartbeat(context, (self.ip, self.hb_port))
         self.hb_port = self.heartbeat.port
         self.log.debug("Heartbeat REP Channel on port: %i"%self.hb_port)
 
         # Helper to make it easier to connect to an existing kernel.
         # set log-level to critical, to make sure it is output
         self.log.critical("To connect another client to this kernel, use:")
         
         basename = os.path.basename(self.connection_file)
         if basename == self.connection_file or \
             os.path.dirname(self.connection_file) == self.profile_dir.security_dir:
             # use shortname
             tail = basename
             if self.profile != 'default':
                 tail += " --profile %s" % self.profile
         else:
             tail = self.connection_file
         self.log.critical("--existing %s", tail)
 
 
         self.ports = dict(shell=self.shell_port, iopub=self.iopub_port,
                                 stdin=self.stdin_port, hb=self.hb_port)
 
     def init_session(self):
         """create our session object"""
         default_secure(self.config)
         self.session = Session(config=self.config, username=u'kernel')
 
     def init_blackhole(self):
         """redirects stdout/stderr to devnull if necessary"""
         if self.no_stdout or self.no_stderr:
             blackhole = file(os.devnull, 'w')
             if self.no_stdout:
                 sys.stdout = sys.__stdout__ = blackhole
             if self.no_stderr:
                 sys.stderr = sys.__stderr__ = blackhole
     
     def init_io(self):
         """Redirect input streams and set a display hook."""
         if self.outstream_class:
             outstream_factory = import_item(str(self.outstream_class))
             sys.stdout = outstream_factory(self.session, self.iopub_socket, u'stdout')
             sys.stderr = outstream_factory(self.session, self.iopub_socket, u'stderr')
         if self.displayhook_class:
             displayhook_factory = import_item(str(self.displayhook_class))
             sys.displayhook = displayhook_factory(self.session, self.iopub_socket)
 
     def init_kernel(self):
         """Create the Kernel object itself"""
         kernel_factory = import_item(str(self.kernel_class))
         self.kernel = kernel_factory(config=self.config, session=self.session,
                                 shell_socket=self.shell_socket,
                                 iopub_socket=self.iopub_socket,
                                 stdin_socket=self.stdin_socket,
                                 log=self.log
         )
         self.kernel.record_ports(self.ports)
 
     @catch_config_error
     def initialize(self, argv=None):
         super(KernelApp, self).initialize(argv)
         self.init_blackhole()
         self.init_connection_file()
         self.init_session()
         self.init_poller()
         self.init_sockets()
         # writing connection file must be *after* init_sockets
         self.write_connection_file()
         self.init_io()
         self.init_kernel()
+        # flush stdout/stderr, so that anything written to these streams during
+        # initialization do not get associated with the first execution request
+        sys.stdout.flush()
+        sys.stderr.flush()
 
     def start(self):
         self.heartbeat.start()
         if self.poller is not None:
             self.poller.start()
         try:
             self.kernel.start()
         except KeyboardInterrupt:
             pass