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Backport PR #2738: Unicode content crashes the pager (console)...
Backport PR #2738: Unicode content crashes the pager (console) We've run into an interesting bug in the astropy project. https://github.com/astropy/astropy/issues/600 When displaying a docstring that contains Unicode and is also long enough that it gets sent to the pager it fails since the docstring can't be sent to the pager as ascii. This crashes in the middle of sending content to the pager, so the shell ends up in an inconsistent state and stops echoing the keyboard etc. The fix (attached) is merely to encode the content sent to the pager in the same encoding as the terminal (`sys.stdout.encoding`). Strictly speaking, this isn't always the right thing to do, since the pager may be configured to expect a different encoding than the terminal, but that is sort of an irrational way to configure a machine... ;) For example, `less`, in the absence of any special environment variables to tell it otherwise, uses the standard `LC*` environment variables to determine what to do, which should be the same mechanism the terminal also uses by default. If anyone can suggest a better fix, I'm all for it. Perhaps it should be configurable, defaulting to `sys.stdout.encoding`?

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remotefunction.py
244 lines | 7.5 KiB | text/x-python | PythonLexer
"""Remote Functions and decorators for Views.
Authors:
* Brian Granger
* Min RK
"""
#-----------------------------------------------------------------------------
# Copyright (C) 2010-2011 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
#-----------------------------------------------------------------------------
from __future__ import division
import sys
import warnings
from IPython.testing.skipdoctest import skip_doctest
from . import map as Map
from .asyncresult import AsyncMapResult
#-----------------------------------------------------------------------------
# Functions and Decorators
#-----------------------------------------------------------------------------
@skip_doctest
def remote(view, block=None, **flags):
"""Turn a function into a remote function.
This method can be used for map:
In [1]: @remote(view,block=True)
...: def func(a):
...: pass
"""
def remote_function(f):
return RemoteFunction(view, f, block=block, **flags)
return remote_function
@skip_doctest
def parallel(view, dist='b', block=None, ordered=True, **flags):
"""Turn a function into a parallel remote function.
This method can be used for map:
In [1]: @parallel(view, block=True)
...: def func(a):
...: pass
"""
def parallel_function(f):
return ParallelFunction(view, f, dist=dist, block=block, ordered=ordered, **flags)
return parallel_function
def getname(f):
"""Get the name of an object.
For use in case of callables that are not functions, and
thus may not have __name__ defined.
Order: f.__name__ > f.name > str(f)
"""
try:
return f.__name__
except:
pass
try:
return f.name
except:
pass
return str(f)
#--------------------------------------------------------------------------
# Classes
#--------------------------------------------------------------------------
class RemoteFunction(object):
"""Turn an existing function into a remote function.
Parameters
----------
view : View instance
The view to be used for execution
f : callable
The function to be wrapped into a remote function
block : bool [default: None]
Whether to wait for results or not. The default behavior is
to use the current `block` attribute of `view`
**flags : remaining kwargs are passed to View.temp_flags
"""
view = None # the remote connection
func = None # the wrapped function
block = None # whether to block
flags = None # dict of extra kwargs for temp_flags
def __init__(self, view, f, block=None, **flags):
self.view = view
self.func = f
self.block=block
self.flags=flags
def __call__(self, *args, **kwargs):
block = self.view.block if self.block is None else self.block
with self.view.temp_flags(block=block, **self.flags):
return self.view.apply(self.func, *args, **kwargs)
class ParallelFunction(RemoteFunction):
"""Class for mapping a function to sequences.
This will distribute the sequences according the a mapper, and call
the function on each sub-sequence. If called via map, then the function
will be called once on each element, rather that each sub-sequence.
Parameters
----------
view : View instance
The view to be used for execution
f : callable
The function to be wrapped into a remote function
dist : str [default: 'b']
The key for which mapObject to use to distribute sequences
options are:
* 'b' : use contiguous chunks in order
* 'r' : use round-robin striping
block : bool [default: None]
Whether to wait for results or not. The default behavior is
to use the current `block` attribute of `view`
chunksize : int or None
The size of chunk to use when breaking up sequences in a load-balanced manner
ordered : bool [default: True]
Whether
**flags : remaining kwargs are passed to View.temp_flags
"""
chunksize=None
ordered=None
mapObject=None
def __init__(self, view, f, dist='b', block=None, chunksize=None, ordered=True, **flags):
super(ParallelFunction, self).__init__(view, f, block=block, **flags)
self.chunksize = chunksize
self.ordered = ordered
mapClass = Map.dists[dist]
self.mapObject = mapClass()
def __call__(self, *sequences):
client = self.view.client
# check that the length of sequences match
len_0 = len(sequences[0])
for s in sequences:
if len(s)!=len_0:
msg = 'all sequences must have equal length, but %i!=%i'%(len_0,len(s))
raise ValueError(msg)
balanced = 'Balanced' in self.view.__class__.__name__
if balanced:
if self.chunksize:
nparts = len_0//self.chunksize + int(len_0%self.chunksize > 0)
else:
nparts = len_0
targets = [None]*nparts
else:
if self.chunksize:
warnings.warn("`chunksize` is ignored unless load balancing", UserWarning)
# multiplexed:
targets = self.view.targets
# 'all' is lazily evaluated at execution time, which is now:
if targets == 'all':
targets = client._build_targets(targets)[1]
elif isinstance(targets, int):
# single-engine view, targets must be iterable
targets = [targets]
nparts = len(targets)
msg_ids = []
for index, t in enumerate(targets):
args = []
for seq in sequences:
part = self.mapObject.getPartition(seq, index, nparts)
if len(part) == 0:
continue
else:
args.append(part)
if not args:
continue
# print (args)
if hasattr(self, '_map'):
if sys.version_info[0] >= 3:
f = lambda f, *sequences: list(map(f, *sequences))
else:
f = map
args = [self.func]+args
else:
f=self.func
view = self.view if balanced else client[t]
with view.temp_flags(block=False, **self.flags):
ar = view.apply(f, *args)
msg_ids.append(ar.msg_ids[0])
r = AsyncMapResult(self.view.client, msg_ids, self.mapObject,
fname=getname(self.func),
ordered=self.ordered
)
if self.block:
try:
return r.get()
except KeyboardInterrupt:
return r
else:
return r
def map(self, *sequences):
"""call a function on each element of a sequence remotely.
This should behave very much like the builtin map, but return an AsyncMapResult
if self.block is False.
"""
# set _map as a flag for use inside self.__call__
self._map = True
try:
ret = self.__call__(*sequences)
finally:
del self._map
return ret
__all__ = ['remote', 'parallel', 'RemoteFunction', 'ParallelFunction']