##// END OF EJS Templates
use Session to protect from fork-unsafe sockets
use Session to protect from fork-unsafe sockets

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iostream.py
157 lines | 5.2 KiB | text/x-python | PythonLexer
import sys
import time
import os
from io import StringIO
from session import extract_header, Message
from IPython.utils import io, text
from IPython.utils import py3compat
import multiprocessing as mp
import multiprocessing.sharedctypes as mpshc
from ctypes import c_bool
#-----------------------------------------------------------------------------
# Globals
#-----------------------------------------------------------------------------
#-----------------------------------------------------------------------------
# Stream classes
#-----------------------------------------------------------------------------
class OutStream(object):
"""A file like object that publishes the stream to a 0MQ PUB socket."""
# The time interval between automatic flushes, in seconds.
flush_interval = 0.05
topic=None
def __init__(self, session, pub_socket, name):
self.encoding = 'UTF-8'
self.session = session
self.pub_socket = pub_socket
self.name = name
self.parent_header = {}
self._new_buffer()
self._manager = mp.Manager()
#use sharectype here so it don't have to hit the manager
#no synchronize needed either(right?). Just a flag telling the master
#to switch the buffer to que
self._found_newprocess = mpshc.RawValue(c_bool, False)
self._que_buffer = self._manager.Queue()
self._que_lock = self._manager.Lock()
self._masterpid = os.getpid()
self._master_has_switched = False
def _switch_to_que(self):
#should only be called on master process
#don't clear the que before putting data in since
#child process might have put something in the que before the
#master know it.
self._que_buffer.put(self._buffer.getvalue())
self._new_buffer()
self._start = -1
def _is_master_process(self):
return os.getpid()==self._masterpid
def _debug_print(self,s):
sys.__stdout__.write(s+'\n')
sys.__stdout__.flush()
def _check_mp_mode(self):
"""check multiprocess and switch to que if necessary"""
if not self._found_newprocess.value:
if not self._is_master_process():
self._found_newprocess.value = True
elif self._found_newprocess.value and not self._master_has_switched:
#switch to que if it has not been switch
if self._is_master_process():
self._switch_to_que()
self._master_has_switched = True
return self._found_newprocess.value
def set_parent(self, parent):
self.parent_header = extract_header(parent)
def close(self):
self.pub_socket = None
def flush(self):
#io.rprint('>>>flushing output buffer: %s<<<' % self.name) # dbg
if self.pub_socket is None:
raise ValueError(u'I/O operation on closed file')
else:
if self._is_master_process():
data = u''
#obtain data
if self._check_mp_mode():#multiprocess
with self._que_lock:
while not self._que_buffer.empty():
data += self._que_buffer.get()
else:#single process mode
data = self._buffer.getvalue()
if data:
content = {u'name':self.name, u'data':data}
msg = self.session.send(self.pub_socket, u'stream', content=content,
parent=self.parent_header, ident=self.topic)
if hasattr(self.pub_socket, 'flush'):
# socket itself has flush (presumably ZMQStream)
self.pub_socket.flush()
self._buffer.close()
self._new_buffer()
else:
pass
def isatty(self):
return False
def __next__(self):
raise IOError('Read not supported on a write only stream.')
if not py3compat.PY3:
next = __next__
def read(self, size=-1):
raise IOError('Read not supported on a write only stream.')
def readline(self, size=-1):
raise IOError('Read not supported on a write only stream.')
def write(self, string):
if self.pub_socket is None:
raise ValueError('I/O operation on closed file')
else:
# Make sure that we're handling unicode
if not isinstance(string, unicode):
string = string.decode(self.encoding, 'replace')
if self._check_mp_mode(): #multi process mode
with self._que_lock:
self._que_buffer.put(string)
else: #sigle process mode
self._buffer.write(string)
current_time = time.time()
if self._start <= 0:
self._start = current_time
elif current_time - self._start > self.flush_interval:
self.flush()
def writelines(self, sequence):
if self.pub_socket is None:
raise ValueError('I/O operation on closed file')
else:
for string in sequence:
self.write(string)
def _new_buffer(self):
self._buffer = StringIO()
self._start = -1