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Ensure crash handler works even when app isn't fully configured yet....
Ensure crash handler works even when app isn't fully configured yet. In such a case, the ipython_dir may not have been computed yet, so we must avoid calling isdir() on a possibly None variable.

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kernelmanager.py
271 lines | 8.0 KiB | text/x-python | PythonLexer
"""Kernel frontend classes.
To do:
1. Create custom channel subclasses for Qt.
2. Create logger to handle debugging and console messages.
"""
from Queue import Queue, Empty
from threading import Thread
import traceback
import zmq
from zmq import POLLIN, POLLOUT, POLLERR
from zmq.eventloop import ioloop
from session import Session
class MissingHandlerError(Exception):
pass
class KernelManager(object):
def __init__(self, xreq_addr, sub_addr, rep_addr,
context=None, session=None):
self.context = zmq.Context() if context is None else context
self.session = Session() if session is None else session
self.xreq_addr = xreq_addr
self.sub_addr = sub_addr
self.rep_addr = rep_addr
def start_kernel(self):
"""Start a localhost kernel on ip and port.
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.
"""
def kill_kernel(self):
"""Kill the running kernel"""
def is_alive(self):
"""Is the kernel alive?"""
return True
def signal_kernel(self, signum):
"""Send signum to the kernel."""
def get_sub_channel(self):
"""Get the SUB socket channel object."""
return SubSocketChannel(self.context, self.session, self.sub_addr)
def get_xreq_channel(self):
"""Get the REQ socket channel object to make requests of the kernel."""
return XReqSocketChannel(self.context, self.session, self.xreq_addr)
def get_rep_channel(self):
"""Get the REP socket channel object to handle stdin (raw_input)."""
return RepSocketChannel(self.context, self.session, self.rep_addr)
class ZmqSocketChannel(Thread):
socket = None
def __init__(self, context, session, addr):
self.context = context
self.session = session
self.addr = addr
super(ZmqSocketChannel, self).__init__()
self.daemon = True
class SubSocketChannel(ZmqSocketChannel):
handlers = None
_overriden_call_handler = None
def __init__(self, context, session, addr):
self.handlers = {}
super(SubSocketChannel, self).__init__(context, session, addr)
def run(self):
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.addr)
self.ioloop = ioloop.IOLoop()
self.ioloop.add_handler(self.socket, self._handle_events,
POLLIN|POLLERR)
self.ioloop.start()
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):
raise zmq.ZmqError()
def _handle_recv(self):
msg = self.socket.recv_json()
self.call_handlers(msg)
def override_call_handler(self, func):
"""Permanently override the call_handler.
The function func will be called as::
func(handler, msg)
And must call::
handler(msg)
in the main thread.
"""
assert callable(func), "not a callable: %r" % func
self._overriden_call_handler = func
def call_handlers(self, msg):
handler = self.handlers.get(msg['msg_type'], None)
if handler is not None:
try:
self.call_handler(handler, msg)
except:
# XXX: This should be logged at least
traceback.print_last()
def call_handler(self, handler, msg):
if self._overriden_call_handler is not None:
self._overriden_call_handler(handler, msg)
elif hasattr(self, '_call_handler'):
call_handler = getattr(self, '_call_handler')
call_handler(handler, msg)
else:
raise RuntimeError('no handler!')
def add_handler(self, callback, msg_type):
"""Register a callback for msg type."""
self.handlers[msg_type] = callback
def remove_handler(self, msg_type):
self.handlers.pop(msg_type, None)
class XReqSocketChannel(ZmqSocketChannel):
handler_queue = None
command_queue = None
handlers = None
_overriden_call_handler = None
def __init__(self, context, session, addr):
self.handlers = {}
self.handler_queue = Queue()
self.command_queue = Queue()
super(XReqSocketChannel, self).__init__(context, session, addr)
def run(self):
self.socket = self.context.socket(zmq.XREQ)
self.socket.setsockopt(zmq.IDENTITY, self.session.session)
self.socket.connect('tcp://%s:%i' % self.addr)
self.ioloop = ioloop.IOLoop()
self.ioloop.add_handler(self.socket, self._handle_events,
POLLIN|POLLOUT|POLLERR)
self.ioloop.start()
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 & POLLOUT:
self._handle_send()
if events & POLLIN:
self._handle_recv()
def _handle_recv(self):
msg = self.socket.recv_json()
print "Got reply:", msg
try:
handler = self.handler_queue.get(False)
except Empty:
print "Message received with no handler!!!"
print msg
else:
self.call_handler(handler, msg)
def _handle_send(self):
try:
msg = self.command_queue.get(False)
except Empty:
pass
else:
self.socket.send_json(msg)
def _handle_err(self):
raise zmq.ZmqError()
def _queue_request(self, msg, callback):
handler = self._find_handler(msg['msg_type'], callback)
self.handler_queue.put(handler)
self.command_queue.put(msg)
def execute(self, code, callback=None):
# Create class for content/msg creation. Related to, but possibly
# not in Session.
content = dict(code=code)
msg = self.session.msg('execute_request', content)
self._queue_request(msg, callback)
return msg['header']['msg_id']
def complete(self, text, line, block=None, callback=None):
content = dict(text=text, line=line)
msg = self.session.msg('complete_request', content)
return self._queue_request(msg, callback)
return msg['header']['msg_id']
def object_info(self, oname, callback=None):
content = dict(oname=oname)
msg = self.session.msg('object_info_request', content)
return self._queue_request(msg, callback)
return msg['header']['msg_id']
def _find_handler(self, name, callback):
if callback is not None:
return callback
handler = self.handlers.get(name)
if handler is None:
raise MissingHandlerError('No handler defined for method: %s' % name)
return handler
def override_call_handler(self, func):
"""Permanently override the call_handler.
The function func will be called as::
func(handler, msg)
And must call::
handler(msg)
in the main thread.
"""
assert callable(func), "not a callable: %r" % func
self._overriden_call_handler = func
def call_handler(self, handler, msg):
if self._overriden_call_handler is not None:
self._overriden_call_handler(handler, msg)
elif hasattr(self, '_call_handler'):
call_handler = getattr(self, '_call_handler')
call_handler(handler, msg)
else:
raise RuntimeError('no handler!')
class RepSocketChannel(ZmqSocketChannel):
def on_raw_input():
pass