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Merge pull request #1391 from minrk/no_engines...
Merge pull request #1391 from minrk/no_engines Improve Hub/Scheduler when no engines are registered 1. Tasks are pulled into the schedule, rather than left on the ZMQ queue, which means they enter the database. 2. queue_status will not raise NoEngines when there aren't any, instead it will still fetch the available information. Bug fixed in db_query, where behavior did not match docstring (buffers should be excluded if no keys are specified). closes #826 (again)

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asyncfrontendbase.py
82 lines | 2.7 KiB | text/x-python | PythonLexer
"""
Base front end class for all async frontends.
"""
__docformat__ = "restructuredtext en"
# Tell nose to skip this module
__test__ = {}
#-------------------------------------------------------------------------------
# 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
#-------------------------------------------------------------------------------
# Third-party
from twisted.python.failure import Failure
from zope.interface import implements, classProvides
# From IPython
from IPython.frontend.frontendbase import (FrontEndBase, IFrontEnd,
IFrontEndFactory)
from IPython.kernel.core.history import FrontEndHistory
from IPython.kernel.engineservice import IEngineCore
import uuid
#-----------------------------------------------------------------------------
# Classes and functions
#-----------------------------------------------------------------------------
class AsyncFrontEndBase(FrontEndBase):
"""
Overrides FrontEndBase to wrap execute in a deferred result.
All callbacks are made as callbacks on the deferred result.
"""
implements(IFrontEnd)
classProvides(IFrontEndFactory)
def __init__(self, engine=None, history=None):
assert(engine==None or IEngineCore.providedBy(engine))
self.engine = IEngineCore(engine)
if history is None:
self.history = FrontEndHistory(input_cache=[''])
else:
self.history = history
def execute(self, block, blockID=None):
"""Execute the block and return the deferred result.
Parameters:
block : {str, AST}
blockID : any
Caller may provide an ID to identify this block.
result['blockID'] := blockID
Result:
Deferred result of self.interpreter.execute
"""
if(not self.is_complete(block)):
return Failure(Exception("Block is not compilable"))
if(blockID == None):
blockID = uuid.uuid4()
d = self.engine.execute(block)
d.addCallback(self._add_history, block=block)
d.addCallbacks(self._add_block_id_for_result,
errback=self._add_block_id_for_failure,
callbackArgs=(blockID,),
errbackArgs=(blockID,))
d.addBoth(self.update_cell_prompt, blockID=blockID)
d.addCallbacks(self.render_result,
errback=self.render_error)
return d