##// END OF EJS Templates
Don't catch ImportError when trying to unpack module functions...
Don't catch ImportError when trying to unpack module functions If the ImportError is encountered, it is more informative to raise it rather than hide it, possibly resulting in confusing NameErrors due to the import failure.

File last commit:

r7938:aa6d4591
r8405:46ee6cb8
Show More
eventloops.py
223 lines | 7.3 KiB | text/x-python | PythonLexer
# encoding: utf-8
"""Event loop integration for the ZeroMQ-based kernels.
"""
#-----------------------------------------------------------------------------
# Copyright (C) 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 sys
# System library imports.
import zmq
# Local imports.
from IPython.config.application import Application
from IPython.utils import io
#------------------------------------------------------------------------------
# Eventloops for integrating the Kernel into different GUIs
#------------------------------------------------------------------------------
def loop_qt4(kernel):
"""Start a kernel with PyQt4 event loop integration."""
from IPython.external.qt_for_kernel import QtCore
from IPython.lib.guisupport import get_app_qt4, start_event_loop_qt4
kernel.app = get_app_qt4([" "])
kernel.app.setQuitOnLastWindowClosed(False)
kernel.timer = QtCore.QTimer()
kernel.timer.timeout.connect(kernel.do_one_iteration)
# Units for the timer are in milliseconds
kernel.timer.start(1000*kernel._poll_interval)
start_event_loop_qt4(kernel.app)
def loop_wx(kernel):
"""Start a kernel with wx event loop support."""
import wx
from IPython.lib.guisupport import start_event_loop_wx
doi = kernel.do_one_iteration
# Wx uses milliseconds
poll_interval = int(1000*kernel._poll_interval)
# We have to put the wx.Timer in a wx.Frame for it to fire properly.
# We make the Frame hidden when we create it in the main app below.
class TimerFrame(wx.Frame):
def __init__(self, func):
wx.Frame.__init__(self, None, -1)
self.timer = wx.Timer(self)
# Units for the timer are in milliseconds
self.timer.Start(poll_interval)
self.Bind(wx.EVT_TIMER, self.on_timer)
self.func = func
def on_timer(self, event):
self.func()
# We need a custom wx.App to create our Frame subclass that has the
# wx.Timer to drive the ZMQ event loop.
class IPWxApp(wx.App):
def OnInit(self):
self.frame = TimerFrame(doi)
self.frame.Show(False)
return True
# The redirect=False here makes sure that wx doesn't replace
# sys.stdout/stderr with its own classes.
kernel.app = IPWxApp(redirect=False)
# The import of wx on Linux sets the handler for signal.SIGINT
# to 0. This is a bug in wx or gtk. We fix by just setting it
# back to the Python default.
import signal
if not callable(signal.getsignal(signal.SIGINT)):
signal.signal(signal.SIGINT, signal.default_int_handler)
start_event_loop_wx(kernel.app)
def loop_tk(kernel):
"""Start a kernel with the Tk event loop."""
import Tkinter
doi = kernel.do_one_iteration
# Tk uses milliseconds
poll_interval = int(1000*kernel._poll_interval)
# For Tkinter, we create a Tk object and call its withdraw method.
class Timer(object):
def __init__(self, func):
self.app = Tkinter.Tk()
self.app.withdraw()
self.func = func
def on_timer(self):
self.func()
self.app.after(poll_interval, self.on_timer)
def start(self):
self.on_timer() # Call it once to get things going.
self.app.mainloop()
kernel.timer = Timer(doi)
kernel.timer.start()
def loop_gtk(kernel):
"""Start the kernel, coordinating with the GTK event loop"""
from .gui.gtkembed import GTKEmbed
gtk_kernel = GTKEmbed(kernel)
gtk_kernel.start()
def loop_cocoa(kernel):
"""Start the kernel, coordinating with the Cocoa CFRunLoop event loop
via the matplotlib MacOSX backend.
"""
import matplotlib
if matplotlib.__version__ < '1.1.0':
kernel.log.warn(
"MacOSX backend in matplotlib %s doesn't have a Timer, "
"falling back on Tk for CFRunLoop integration. Note that "
"even this won't work if Tk is linked against X11 instead of "
"Cocoa (e.g. EPD). To use the MacOSX backend in the kernel, "
"you must use matplotlib >= 1.1.0, or a native libtk."
)
return loop_tk(kernel)
from matplotlib.backends.backend_macosx import TimerMac, show
# scale interval for sec->ms
poll_interval = int(1000*kernel._poll_interval)
real_excepthook = sys.excepthook
def handle_int(etype, value, tb):
"""don't let KeyboardInterrupts look like crashes"""
if etype is KeyboardInterrupt:
io.raw_print("KeyboardInterrupt caught in CFRunLoop")
else:
real_excepthook(etype, value, tb)
# add doi() as a Timer to the CFRunLoop
def doi():
# restore excepthook during IPython code
sys.excepthook = real_excepthook
kernel.do_one_iteration()
# and back:
sys.excepthook = handle_int
t = TimerMac(poll_interval)
t.add_callback(doi)
t.start()
# but still need a Poller for when there are no active windows,
# during which time mainloop() returns immediately
poller = zmq.Poller()
if kernel.control_stream:
poller.register(kernel.control_stream.socket, zmq.POLLIN)
for stream in kernel.shell_streams:
poller.register(stream.socket, zmq.POLLIN)
while True:
try:
# double nested try/except, to properly catch KeyboardInterrupt
# due to pyzmq Issue #130
try:
# don't let interrupts during mainloop invoke crash_handler:
sys.excepthook = handle_int
show.mainloop()
sys.excepthook = real_excepthook
# use poller if mainloop returned (no windows)
# scale by extra factor of 10, since it's a real poll
poller.poll(10*poll_interval)
kernel.do_one_iteration()
except:
raise
except KeyboardInterrupt:
# Ctrl-C shouldn't crash the kernel
io.raw_print("KeyboardInterrupt caught in kernel")
finally:
# ensure excepthook is restored
sys.excepthook = real_excepthook
# mapping of keys to loop functions
loop_map = {
'qt' : loop_qt4,
'qt4': loop_qt4,
'inline': None,
'osx': loop_cocoa,
'wx' : loop_wx,
'tk' : loop_tk,
'gtk': loop_gtk,
None : None,
}
def enable_gui(gui, kernel=None):
"""Enable integration with a given GUI"""
if gui not in loop_map:
raise ValueError("GUI %r not supported" % gui)
if kernel is None:
if Application.initialized():
kernel = getattr(Application.instance(), 'kernel', None)
if kernel is None:
raise RuntimeError("You didn't specify a kernel,"
" and no IPython Application with a kernel appears to be running."
)
loop = loop_map[gui]
if loop and kernel.eventloop is not None and kernel.eventloop is not loop:
raise RuntimeError("Cannot activate multiple GUI eventloops")
kernel.eventloop = loop