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streamsession.py
419 lines | 13.6 KiB | text/x-python | PythonLexer
#!/usr/bin/env python
"""edited session.py to work with streams, and move msg_type to the header
"""
#-----------------------------------------------------------------------------
# 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.
#-----------------------------------------------------------------------------
import os
import pprint
import uuid
from datetime import datetime
try:
import cPickle
pickle = cPickle
except:
cPickle = None
import pickle
import zmq
from zmq.utils import jsonapi
from zmq.eventloop.zmqstream import ZMQStream
from .util import ISO8601
def squash_unicode(obj):
"""coerce unicode back to bytestrings."""
if isinstance(obj,dict):
for key in obj.keys():
obj[key] = squash_unicode(obj[key])
if isinstance(key, unicode):
obj[squash_unicode(key)] = obj.pop(key)
elif isinstance(obj, list):
for i,v in enumerate(obj):
obj[i] = squash_unicode(v)
elif isinstance(obj, unicode):
obj = obj.encode('utf8')
return obj
def _date_default(obj):
if isinstance(obj, datetime):
return obj.strftime(ISO8601)
else:
raise TypeError("%r is not JSON serializable"%obj)
_default_key = 'on_unknown' if jsonapi.jsonmod.__name__ == 'jsonlib' else 'default'
json_packer = lambda obj: jsonapi.dumps(obj, **{_default_key:_date_default})
json_unpacker = lambda s: squash_unicode(jsonapi.loads(s))
pickle_packer = lambda o: pickle.dumps(o,-1)
pickle_unpacker = pickle.loads
default_packer = json_packer
default_unpacker = json_unpacker
DELIM="<IDS|MSG>"
class Message(object):
"""A simple message object that maps dict keys to attributes.
A Message can be created from a dict and a dict from a Message instance
simply by calling dict(msg_obj)."""
def __init__(self, msg_dict):
dct = self.__dict__
for k, v in dict(msg_dict).iteritems():
if isinstance(v, dict):
v = Message(v)
dct[k] = v
# Having this iterator lets dict(msg_obj) work out of the box.
def __iter__(self):
return iter(self.__dict__.iteritems())
def __repr__(self):
return repr(self.__dict__)
def __str__(self):
return pprint.pformat(self.__dict__)
def __contains__(self, k):
return k in self.__dict__
def __getitem__(self, k):
return self.__dict__[k]
def msg_header(msg_id, msg_type, username, session):
date=datetime.now().strftime(ISO8601)
return locals()
def extract_header(msg_or_header):
"""Given a message or header, return the header."""
if not msg_or_header:
return {}
try:
# See if msg_or_header is the entire message.
h = msg_or_header['header']
except KeyError:
try:
# See if msg_or_header is just the header
h = msg_or_header['msg_id']
except KeyError:
raise
else:
h = msg_or_header
if not isinstance(h, dict):
h = dict(h)
return h
class StreamSession(object):
"""tweaked version of IPython.zmq.session.Session, for development in Parallel"""
debug=False
key=None
def __init__(self, username=None, session=None, packer=None, unpacker=None, key=None, keyfile=None):
if username is None:
username = os.environ.get('USER','username')
self.username = username
if session is None:
self.session = str(uuid.uuid4())
else:
self.session = session
self.msg_id = str(uuid.uuid4())
if packer is None:
self.pack = default_packer
else:
if not callable(packer):
raise TypeError("packer must be callable, not %s"%type(packer))
self.pack = packer
if unpacker is None:
self.unpack = default_unpacker
else:
if not callable(unpacker):
raise TypeError("unpacker must be callable, not %s"%type(unpacker))
self.unpack = unpacker
if key is not None and keyfile is not None:
raise TypeError("Must specify key OR keyfile, not both")
if keyfile is not None:
with open(keyfile) as f:
self.key = f.read().strip()
else:
self.key = key
if isinstance(self.key, unicode):
self.key = self.key.encode('utf8')
# print key, keyfile, self.key
self.none = self.pack({})
def msg_header(self, msg_type):
h = msg_header(self.msg_id, msg_type, self.username, self.session)
self.msg_id = str(uuid.uuid4())
return h
def msg(self, msg_type, content=None, parent=None, subheader=None):
msg = {}
msg['header'] = self.msg_header(msg_type)
msg['msg_id'] = msg['header']['msg_id']
msg['parent_header'] = {} if parent is None else extract_header(parent)
msg['msg_type'] = msg_type
msg['content'] = {} if content is None else content
sub = {} if subheader is None else subheader
msg['header'].update(sub)
return msg
def check_key(self, msg_or_header):
"""Check that a message's header has the right key"""
if self.key is None:
return True
header = extract_header(msg_or_header)
return header.get('key', None) == self.key
def serialize(self, msg, ident=None):
content = msg.get('content', {})
if content is None:
content = self.none
elif isinstance(content, dict):
content = self.pack(content)
elif isinstance(content, bytes):
# content is already packed, as in a relayed message
pass
elif isinstance(content, unicode):
# should be bytes, but JSON often spits out unicode
content = content.encode('utf8')
else:
raise TypeError("Content incorrect type: %s"%type(content))
to_send = []
if isinstance(ident, list):
# accept list of idents
to_send.extend(ident)
elif ident is not None:
to_send.append(ident)
to_send.append(DELIM)
if self.key is not None:
to_send.append(self.key)
to_send.append(self.pack(msg['header']))
to_send.append(self.pack(msg['parent_header']))
to_send.append(content)
return to_send
def send(self, stream, msg_or_type, content=None, buffers=None, parent=None, subheader=None, ident=None, track=False):
"""Build and send a message via stream or socket.
Parameters
----------
stream : zmq.Socket or ZMQStream
the socket-like object used to send the data
msg_or_type : str or Message/dict
Normally, msg_or_type will be a msg_type unless a message is being sent more
than once.
content : dict or None
the content of the message (ignored if msg_or_type is a message)
buffers : list or None
the already-serialized buffers to be appended to the message
parent : Message or dict or None
the parent or parent header describing the parent of this message
subheader : dict or None
extra header keys for this message's header
ident : bytes or list of bytes
the zmq.IDENTITY routing path
track : bool
whether to track. Only for use with Sockets, because ZMQStream objects cannot track messages.
Returns
-------
msg : message dict
the constructed message
(msg,tracker) : (message dict, MessageTracker)
if track=True, then a 2-tuple will be returned, the first element being the constructed
message, and the second being the MessageTracker
"""
if not isinstance(stream, (zmq.Socket, ZMQStream)):
raise TypeError("stream must be Socket or ZMQStream, not %r"%type(stream))
elif track and isinstance(stream, ZMQStream):
raise TypeError("ZMQStream cannot track messages")
if isinstance(msg_or_type, (Message, dict)):
# we got a Message, not a msg_type
# don't build a new Message
msg = msg_or_type
else:
msg = self.msg(msg_or_type, content, parent, subheader)
buffers = [] if buffers is None else buffers
to_send = self.serialize(msg, ident)
flag = 0
if buffers:
flag = zmq.SNDMORE
_track = False
else:
_track=track
if track:
tracker = stream.send_multipart(to_send, flag, copy=False, track=_track)
else:
tracker = stream.send_multipart(to_send, flag, copy=False)
for b in buffers[:-1]:
stream.send(b, flag, copy=False)
if buffers:
if track:
tracker = stream.send(buffers[-1], copy=False, track=track)
else:
tracker = stream.send(buffers[-1], copy=False)
# omsg = Message(msg)
if self.debug:
pprint.pprint(msg)
pprint.pprint(to_send)
pprint.pprint(buffers)
msg['tracker'] = tracker
return msg
def send_raw(self, stream, msg, flags=0, copy=True, ident=None):
"""Send a raw message via ident path.
Parameters
----------
msg : list of sendable buffers"""
to_send = []
if isinstance(ident, bytes):
ident = [ident]
if ident is not None:
to_send.extend(ident)
to_send.append(DELIM)
if self.key is not None:
to_send.append(self.key)
to_send.extend(msg)
stream.send_multipart(msg, flags, copy=copy)
def recv(self, socket, mode=zmq.NOBLOCK, content=True, copy=True):
"""receives and unpacks a message
returns [idents], msg"""
if isinstance(socket, ZMQStream):
socket = socket.socket
try:
msg = socket.recv_multipart(mode)
except zmq.ZMQError as e:
if e.errno == zmq.EAGAIN:
# We can convert EAGAIN to None as we know in this case
# recv_multipart won't return None.
return None
else:
raise
# return an actual Message object
# determine the number of idents by trying to unpack them.
# this is terrible:
idents, msg = self.feed_identities(msg, copy)
try:
return idents, self.unpack_message(msg, content=content, copy=copy)
except Exception as e:
print (idents, msg)
# TODO: handle it
raise e
def feed_identities(self, msg, copy=True):
"""feed until DELIM is reached, then return the prefix as idents and remainder as
msg. This is easily broken by setting an IDENT to DELIM, but that would be silly.
Parameters
----------
msg : a list of Message or bytes objects
the message to be split
copy : bool
flag determining whether the arguments are bytes or Messages
Returns
-------
(idents,msg) : two lists
idents will always be a list of bytes - the indentity prefix
msg will be a list of bytes or Messages, unchanged from input
msg should be unpackable via self.unpack_message at this point.
"""
ikey = int(self.key is not None)
minlen = 3 + ikey
msg = list(msg)
idents = []
while len(msg) > minlen:
if copy:
s = msg[0]
else:
s = msg[0].bytes
if s == DELIM:
msg.pop(0)
break
else:
idents.append(s)
msg.pop(0)
return idents, msg
def unpack_message(self, msg, content=True, copy=True):
"""Return a message object from the format
sent by self.send.
Parameters:
-----------
content : bool (True)
whether to unpack the content dict (True),
or leave it serialized (False)
copy : bool (True)
whether to return the bytes (True),
or the non-copying Message object in each place (False)
"""
ikey = int(self.key is not None)
minlen = 3 + ikey
message = {}
if not copy:
for i in range(minlen):
msg[i] = msg[i].bytes
if ikey:
if not self.key == msg[0]:
raise KeyError("Invalid Session Key: %s"%msg[0])
if not len(msg) >= minlen:
raise TypeError("malformed message, must have at least %i elements"%minlen)
message['header'] = self.unpack(msg[ikey+0])
message['msg_type'] = message['header']['msg_type']
message['parent_header'] = self.unpack(msg[ikey+1])
if content:
message['content'] = self.unpack(msg[ikey+2])
else:
message['content'] = msg[ikey+2]
message['buffers'] = msg[ikey+3:]# [ m.buffer for m in msg[3:] ]
return message
def test_msg2obj():
am = dict(x=1)
ao = Message(am)
assert ao.x == am['x']
am['y'] = dict(z=1)
ao = Message(am)
assert ao.y.z == am['y']['z']
k1, k2 = 'y', 'z'
assert ao[k1][k2] == am[k1][k2]
am2 = dict(ao)
assert am['x'] == am2['x']
assert am['y']['z'] == am2['y']['z']