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Fixing bug in guisupport.py
Fixing bug in guisupport.py

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kernelmanager.py
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"""Base classes to manage the interaction with a running kernel.
Todo
====
* Create logger to handle debugging and console messages.
"""
#-----------------------------------------------------------------------------
# Copyright (C) 2008-2010 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
#-----------------------------------------------------------------------------
# Standard library imports.
from Queue import Queue, Empty
from subprocess import Popen
from threading import Thread
import time
# System library imports.
import zmq
from zmq import POLLIN, POLLOUT, POLLERR
from zmq.eventloop import ioloop
# Local imports.
from IPython.utils import io
from IPython.utils.traitlets import HasTraits, Any, Instance, Type, TCPAddress
from session import Session
#-----------------------------------------------------------------------------
# Constants and exceptions
#-----------------------------------------------------------------------------
LOCALHOST = '127.0.0.1'
class InvalidPortNumber(Exception):
pass
#-----------------------------------------------------------------------------
# Utility functions
#-----------------------------------------------------------------------------
# some utilities to validate message structure, these might get moved elsewhere
# if they prove to have more generic utility
def validate_string_list(lst):
"""Validate that the input is a list of strings.
Raises ValueError if not."""
if not isinstance(lst, list):
raise ValueError('input %r must be a list' % lst)
for x in lst:
if not isinstance(x, basestring):
raise ValueError('element %r in list must be a string' % x)
def validate_string_dict(dct):
"""Validate that the input is a dict with string keys and values.
Raises ValueError if not."""
for k,v in dct.iteritems():
if not isinstance(k, basestring):
raise ValueError('key %r in dict must be a string' % k)
if not isinstance(v, basestring):
raise ValueError('value %r in dict must be a string' % v)
#-----------------------------------------------------------------------------
# ZMQ Socket Channel classes
#-----------------------------------------------------------------------------
class ZmqSocketChannel(Thread):
"""The base class for the channels that use ZMQ sockets.
"""
context = None
session = None
socket = None
ioloop = None
iostate = None
_address = None
def __init__(self, context, session, address):
"""Create a channel
Parameters
----------
context : :class:`zmq.Context`
The ZMQ context to use.
session : :class:`session.Session`
The session to use.
address : tuple
Standard (ip, port) tuple that the kernel is listening on.
"""
super(ZmqSocketChannel, self).__init__()
self.daemon = True
self.context = context
self.session = session
if address[1] == 0:
message = 'The port number for a channel cannot be 0.'
raise InvalidPortNumber(message)
self._address = address
def stop(self):
"""Stop the channel's activity.
This calls :method:`Thread.join` and returns when the thread
terminates. :class:`RuntimeError` will be raised if
:method:`self.start` is called again.
"""
self.join()
@property
def address(self):
"""Get the channel's address as an (ip, port) tuple.
By the default, the address is (localhost, 0), where 0 means a random
port.
"""
return self._address
def add_io_state(self, state):
"""Add IO state to the eventloop.
Parameters
----------
state : zmq.POLLIN|zmq.POLLOUT|zmq.POLLERR
The IO state flag to set.
This is thread safe as it uses the thread safe IOLoop.add_callback.
"""
def add_io_state_callback():
if not self.iostate & state:
self.iostate = self.iostate | state
self.ioloop.update_handler(self.socket, self.iostate)
self.ioloop.add_callback(add_io_state_callback)
def drop_io_state(self, state):
"""Drop IO state from the eventloop.
Parameters
----------
state : zmq.POLLIN|zmq.POLLOUT|zmq.POLLERR
The IO state flag to set.
This is thread safe as it uses the thread safe IOLoop.add_callback.
"""
def drop_io_state_callback():
if self.iostate & state:
self.iostate = self.iostate & (~state)
self.ioloop.update_handler(self.socket, self.iostate)
self.ioloop.add_callback(drop_io_state_callback)
class XReqSocketChannel(ZmqSocketChannel):
"""The XREQ channel for issues request/replies to the kernel.
"""
command_queue = None
def __init__(self, context, session, address):
self.command_queue = Queue()
super(XReqSocketChannel, self).__init__(context, session, address)
def run(self):
"""The thread's main activity. Call start() instead."""
self.socket = self.context.socket(zmq.XREQ)
self.socket.setsockopt(zmq.IDENTITY, self.session.session)
self.socket.connect('tcp://%s:%i' % self.address)
self.ioloop = ioloop.IOLoop()
self.iostate = POLLERR|POLLIN
self.ioloop.add_handler(self.socket, self._handle_events,
self.iostate)
self.ioloop.start()
def stop(self):
self.ioloop.stop()
super(XReqSocketChannel, self).stop()
def call_handlers(self, msg):
"""This method is called in the ioloop thread when a message arrives.
Subclasses should override this method to handle incoming messages.
It is important to remember that this method is called in the thread
so that some logic must be done to ensure that the application leve
handlers are called in the application thread.
"""
raise NotImplementedError('call_handlers must be defined in a subclass.')
def execute(self, code, silent=False,
user_variables=None, user_expressions=None):
"""Execute code in the kernel.
Parameters
----------
code : str
A string of Python code.
silent : bool, optional (default False)
If set, the kernel will execute the code as quietly possible.
user_variables : list, optional
A list of variable names to pull from the user's namespace. They
will come back as a dict with these names as keys and their
:func:`repr` as values.
user_expressions : dict, optional
A dict with string keys and to pull from the user's
namespace. They will come back as a dict with these names as keys
and their :func:`repr` as values.
Returns
-------
The msg_id of the message sent.
"""
if user_variables is None:
user_variables = []
if user_expressions is None:
user_expressions = {}
# Don't waste network traffic if inputs are invalid
if not isinstance(code, basestring):
raise ValueError('code %r must be a string' % code)
validate_string_list(user_variables)
validate_string_dict(user_expressions)
# Create class for content/msg creation. Related to, but possibly
# not in Session.
content = dict(code=code, silent=silent,
user_variables=user_variables,
user_expressions=user_expressions)
msg = self.session.msg('execute_request', content)
self._queue_request(msg)
return msg['header']['msg_id']
def complete(self, text, line, cursor_pos, block=None):
"""Tab complete text in the kernel's namespace.
Parameters
----------
text : str
The text to complete.
line : str
The full line of text that is the surrounding context for the
text to complete.
cursor_pos : int
The position of the cursor in the line where the completion was
requested.
block : str, optional
The full block of code in which the completion is being requested.
Returns
-------
The msg_id of the message sent.
"""
content = dict(text=text, line=line, block=block, cursor_pos=cursor_pos)
msg = self.session.msg('complete_request', content)
self._queue_request(msg)
return msg['header']['msg_id']
def object_info(self, oname):
"""Get metadata information about an object.
Parameters
----------
oname : str
A string specifying the object name.
Returns
-------
The msg_id of the message sent.
"""
content = dict(oname=oname)
msg = self.session.msg('object_info_request', content)
self._queue_request(msg)
return msg['header']['msg_id']
def history(self, index=None, raw=False, output=True):
"""Get the history list.
Parameters
----------
index : n or (n1, n2) or None
If n, then the last entries. If a tuple, then all in
range(n1, n2). If None, then all entries. Raises IndexError if
the format of index is incorrect.
raw : bool
If True, return the raw input.
output : bool
If True, then return the output as well.
Returns
-------
The msg_id of the message sent.
"""
content = dict(index=index, raw=raw, output=output)
msg = self.session.msg('history_request', content)
self._queue_request(msg)
return msg['header']['msg_id']
def _handle_events(self, socket, events):
if events & POLLERR:
self._handle_err()
if events & POLLOUT:
self._handle_send()
if events & POLLIN:
self._handle_recv()
def _handle_recv(self):
msg = self.socket.recv_json()
self.call_handlers(msg)
def _handle_send(self):
try:
msg = self.command_queue.get(False)
except Empty:
pass
else:
self.socket.send_json(msg)
if self.command_queue.empty():
self.drop_io_state(POLLOUT)
def _handle_err(self):
# We don't want to let this go silently, so eventually we should log.
raise zmq.ZMQError()
def _queue_request(self, msg):
self.command_queue.put(msg)
self.add_io_state(POLLOUT)
class SubSocketChannel(ZmqSocketChannel):
"""The SUB channel which listens for messages that the kernel publishes.
"""
def __init__(self, context, session, address):
super(SubSocketChannel, self).__init__(context, session, address)
def run(self):
"""The thread's main activity. Call start() instead."""
self.socket = self.context.socket(zmq.SUB)
self.socket.setsockopt(zmq.SUBSCRIBE,'')
self.socket.setsockopt(zmq.IDENTITY, self.session.session)
self.socket.connect('tcp://%s:%i' % self.address)
self.ioloop = ioloop.IOLoop()
self.iostate = POLLIN|POLLERR
self.ioloop.add_handler(self.socket, self._handle_events,
self.iostate)
self.ioloop.start()
def stop(self):
self.ioloop.stop()
super(SubSocketChannel, self).stop()
def call_handlers(self, msg):
"""This method is called in the ioloop thread when a message arrives.
Subclasses should override this method to handle incoming messages.
It is important to remember that this method is called in the thread
so that some logic must be done to ensure that the application leve
handlers are called in the application thread.
"""
raise NotImplementedError('call_handlers must be defined in a subclass.')
def flush(self, timeout=1.0):
"""Immediately processes all pending messages on the SUB channel.
Callers should use this method to ensure that :method:`call_handlers`
has been called for all messages that have been received on the
0MQ SUB socket of this channel.
This method is thread safe.
Parameters
----------
timeout : float, optional
The maximum amount of time to spend flushing, in seconds. The
default is one second.
"""
# We do the IOLoop callback process twice to ensure that the IOLoop
# gets to perform at least one full poll.
stop_time = time.time() + timeout
for i in xrange(2):
self._flushed = False
self.ioloop.add_callback(self._flush)
while not self._flushed and time.time() < stop_time:
time.sleep(0.01)
def _handle_events(self, socket, events):
# Turn on and off POLLOUT depending on if we have made a request
if events & POLLERR:
self._handle_err()
if events & POLLIN:
self._handle_recv()
def _handle_err(self):
# We don't want to let this go silently, so eventually we should log.
raise zmq.ZMQError()
def _handle_recv(self):
# Get all of the messages we can
while True:
try:
msg = self.socket.recv_json(zmq.NOBLOCK)
except zmq.ZMQError:
# Check the errno?
# Will this trigger POLLERR?
break
else:
self.call_handlers(msg)
def _flush(self):
"""Callback for :method:`self.flush`."""
self._flushed = True
class RepSocketChannel(ZmqSocketChannel):
"""A reply channel to handle raw_input requests that the kernel makes."""
msg_queue = None
def __init__(self, context, session, address):
self.msg_queue = Queue()
super(RepSocketChannel, self).__init__(context, session, address)
def run(self):
"""The thread's main activity. Call start() instead."""
self.socket = self.context.socket(zmq.XREQ)
self.socket.setsockopt(zmq.IDENTITY, self.session.session)
self.socket.connect('tcp://%s:%i' % self.address)
self.ioloop = ioloop.IOLoop()
self.iostate = POLLERR|POLLIN
self.ioloop.add_handler(self.socket, self._handle_events,
self.iostate)
self.ioloop.start()
def stop(self):
self.ioloop.stop()
super(RepSocketChannel, self).stop()
def call_handlers(self, msg):
"""This method is called in the ioloop thread when a message arrives.
Subclasses should override this method to handle incoming messages.
It is important to remember that this method is called in the thread
so that some logic must be done to ensure that the application leve
handlers are called in the application thread.
"""
raise NotImplementedError('call_handlers must be defined in a subclass.')
def input(self, string):
"""Send a string of raw input to the kernel."""
content = dict(value=string)
msg = self.session.msg('input_reply', content)
self._queue_reply(msg)
def _handle_events(self, socket, events):
if events & POLLERR:
self._handle_err()
if events & POLLOUT:
self._handle_send()
if events & POLLIN:
self._handle_recv()
def _handle_recv(self):
msg = self.socket.recv_json()
self.call_handlers(msg)
def _handle_send(self):
try:
msg = self.msg_queue.get(False)
except Empty:
pass
else:
self.socket.send_json(msg)
if self.msg_queue.empty():
self.drop_io_state(POLLOUT)
def _handle_err(self):
# We don't want to let this go silently, so eventually we should log.
raise zmq.ZMQError()
def _queue_reply(self, msg):
self.msg_queue.put(msg)
self.add_io_state(POLLOUT)
class HBSocketChannel(ZmqSocketChannel):
"""The heartbeat channel which monitors the kernel heartbeat."""
time_to_dead = 3.0
socket = None
poller = None
def __init__(self, context, session, address):
super(HBSocketChannel, self).__init__(context, session, address)
self._running = False
def _create_socket(self):
self.socket = self.context.socket(zmq.REQ)
self.socket.setsockopt(zmq.IDENTITY, self.session.session)
self.socket.connect('tcp://%s:%i' % self.address)
self.poller = zmq.Poller()
self.poller.register(self.socket, zmq.POLLIN)
def run(self):
"""The thread's main activity. Call start() instead."""
self._create_socket()
self._running = True
# Wait 2 seconds for the kernel to come up and the sockets to auto
# connect. If we don't we will see the kernel as dead. Also, before
# the sockets are connected, the poller.poll line below is returning
# too fast. This avoids that because the polling doesn't start until
# after the sockets are connected.
time.sleep(2.0)
while self._running:
since_last_heartbeat = 0.0
request_time = time.time()
try:
#io.rprint('Ping from HB channel') # dbg
self.socket.send_json('ping')
except zmq.ZMQError, e:
#io.rprint('*** HB Error:', e) # dbg
if e.errno == zmq.EFSM:
#io.rprint('sleep...', self.time_to_dead) # dbg
time.sleep(self.time_to_dead)
self._create_socket()
else:
raise
else:
while True:
try:
self.socket.recv_json(zmq.NOBLOCK)
except zmq.ZMQError, e:
#io.rprint('*** HB Error 2:', e) # dbg
if e.errno == zmq.EAGAIN:
before_poll = time.time()
until_dead = self.time_to_dead - (before_poll -
request_time)
# When the return value of poll() is an empty list,
# that is when things have gone wrong (zeromq bug).
# As long as it is not an empty list, poll is
# working correctly even if it returns quickly.
# Note: poll timeout is in milliseconds.
self.poller.poll(1000*until_dead)
since_last_heartbeat = time.time() - request_time
if since_last_heartbeat > self.time_to_dead:
self.call_handlers(since_last_heartbeat)
break
else:
# FIXME: We should probably log this instead.
raise
else:
until_dead = self.time_to_dead - (time.time() -
request_time)
if until_dead > 0.0:
#io.rprint('sleep...', self.time_to_dead) # dbg
time.sleep(until_dead)
break
def stop(self):
self._running = False
super(HBSocketChannel, self).stop()
def call_handlers(self, since_last_heartbeat):
"""This method is called in the ioloop thread when a message arrives.
Subclasses should override this method to handle incoming messages.
It is important to remember that this method is called in the thread
so that some logic must be done to ensure that the application leve
handlers are called in the application thread.
"""
raise NotImplementedError('call_handlers must be defined in a subclass.')
#-----------------------------------------------------------------------------
# Main kernel manager class
#-----------------------------------------------------------------------------
class KernelManager(HasTraits):
""" Manages a kernel for a frontend.
The SUB channel is for the frontend to receive messages published by the
kernel.
The REQ channel is for the frontend to make requests of the kernel.
The REP channel is for the kernel to request stdin (raw_input) from the
frontend.
"""
# The PyZMQ Context to use for communication with the kernel.
context = Instance(zmq.Context,(),{})
# The Session to use for communication with the kernel.
session = Instance(Session,(),{})
# The kernel process with which the KernelManager is communicating.
kernel = Instance(Popen)
# The addresses for the communication channels.
xreq_address = TCPAddress((LOCALHOST, 0))
sub_address = TCPAddress((LOCALHOST, 0))
rep_address = TCPAddress((LOCALHOST, 0))
hb_address = TCPAddress((LOCALHOST, 0))
# The classes to use for the various channels.
xreq_channel_class = Type(XReqSocketChannel)
sub_channel_class = Type(SubSocketChannel)
rep_channel_class = Type(RepSocketChannel)
hb_channel_class = Type(HBSocketChannel)
# Protected traits.
_launch_args = Any
_xreq_channel = Any
_sub_channel = Any
_rep_channel = Any
_hb_channel = Any
#--------------------------------------------------------------------------
# Channel management methods:
#--------------------------------------------------------------------------
def start_channels(self):
"""Starts the channels for this kernel.
This will create the channels if they do not exist and then start
them. If port numbers of 0 are being used (random ports) then you
must first call :method:`start_kernel`. If the channels have been
stopped and you call this, :class:`RuntimeError` will be raised.
"""
self.xreq_channel.start()
self.sub_channel.start()
self.rep_channel.start()
self.hb_channel.start()
def stop_channels(self):
"""Stops the channels for this kernel.
This stops the channels by joining their threads. If the channels
were not started, :class:`RuntimeError` will be raised.
"""
self.xreq_channel.stop()
self.sub_channel.stop()
self.rep_channel.stop()
self.hb_channel.stop()
@property
def channels_running(self):
"""Are all of the channels created and running?"""
return self.xreq_channel.is_alive() \
and self.sub_channel.is_alive() \
and self.rep_channel.is_alive() \
and self.hb_channel.is_alive()
#--------------------------------------------------------------------------
# Kernel process management methods:
#--------------------------------------------------------------------------
def start_kernel(self, **kw):
"""Starts a kernel process and configures the manager to use it.
If random ports (port=0) are being used, this method must be called
before the channels are created.
Parameters:
-----------
ipython : bool, optional (default True)
Whether to use an IPython kernel instead of a plain Python kernel.
"""
xreq, sub, rep, hb = self.xreq_address, self.sub_address, \
self.rep_address, self.hb_address
if xreq[0] != LOCALHOST or sub[0] != LOCALHOST or \
rep[0] != LOCALHOST or hb[0] != LOCALHOST:
raise RuntimeError("Can only launch a kernel on localhost."
"Make sure that the '*_address' attributes are "
"configured properly.")
self._launch_args = kw.copy()
if kw.pop('ipython', True):
from ipkernel import launch_kernel as launch
else:
from pykernel import launch_kernel as launch
self.kernel, xrep, pub, req, hb = launch(
xrep_port=xreq[1], pub_port=sub[1],
req_port=rep[1], hb_port=hb[1], **kw)
self.xreq_address = (LOCALHOST, xrep)
self.sub_address = (LOCALHOST, pub)
self.rep_address = (LOCALHOST, req)
self.hb_address = (LOCALHOST, hb)
def restart_kernel(self):
"""Restarts a kernel with the same arguments that were used to launch
it. If the old kernel was launched with random ports, the same ports
will be used for the new kernel.
"""
if self._launch_args is None:
raise RuntimeError("Cannot restart the kernel. "
"No previous call to 'start_kernel'.")
else:
if self.has_kernel:
self.kill_kernel()
self.start_kernel(**self._launch_args)
@property
def has_kernel(self):
"""Returns whether a kernel process has been specified for the kernel
manager.
"""
return self.kernel is not None
def kill_kernel(self):
""" Kill the running kernel. """
if self.kernel is not None:
self.kernel.kill()
self.kernel = None
else:
raise RuntimeError("Cannot kill kernel. No kernel is running!")
def signal_kernel(self, signum):
""" Sends a signal to the kernel. """
if self.kernel is not None:
self.kernel.send_signal(signum)
else:
raise RuntimeError("Cannot signal kernel. No kernel is running!")
@property
def is_alive(self):
"""Is the kernel process still running?"""
if self.kernel is not None:
if self.kernel.poll() is None:
return True
else:
return False
else:
# We didn't start the kernel with this KernelManager so we don't
# know if it is running. We should use a heartbeat for this case.
return True
#--------------------------------------------------------------------------
# Channels used for communication with the kernel:
#--------------------------------------------------------------------------
@property
def xreq_channel(self):
"""Get the REQ socket channel object to make requests of the kernel."""
if self._xreq_channel is None:
self._xreq_channel = self.xreq_channel_class(self.context,
self.session,
self.xreq_address)
return self._xreq_channel
@property
def sub_channel(self):
"""Get the SUB socket channel object."""
if self._sub_channel is None:
self._sub_channel = self.sub_channel_class(self.context,
self.session,
self.sub_address)
return self._sub_channel
@property
def rep_channel(self):
"""Get the REP socket channel object to handle stdin (raw_input)."""
if self._rep_channel is None:
self._rep_channel = self.rep_channel_class(self.context,
self.session,
self.rep_address)
return self._rep_channel
@property
def hb_channel(self):
"""Get the REP socket channel object to handle stdin (raw_input)."""
if self._hb_channel is None:
self._hb_channel = self.hb_channel_class(self.context,
self.session,
self.hb_address)
return self._hb_channel