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""" |
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process.py |
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Created by Thomas Mangin on 2011-05-02. |
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Copyright (c) 2009-2017 Exa Networks. All rights reserved. |
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License: 3-clause BSD. (See the COPYRIGHT file) |
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""" |
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import os |
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import errno |
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import time |
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import subprocess |
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import select |
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import fcntl |
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from exabgp.util import str_ascii |
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from exabgp.util import bytes_ascii |
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from exabgp.util.errstr import errstr |
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from exabgp.reactor.network.error import error |
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from exabgp.configuration.core.format import formated |
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from exabgp.reactor.api.response import Response |
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from exabgp.reactor.api.response.answer import Answer |
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from exabgp.bgp.message import Message |
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from exabgp.logger import Logger |
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from exabgp.version import json as json_version |
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from exabgp.version import text as text_version |
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from exabgp.configuration.environment import environment |
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from threading import Thread |
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# pylint: disable=no-self-argument,not-callable,unused-argument,invalid-name |
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class ProcessError (Exception): |
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pass |
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def preexec_helper (): |
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# make this process a new process group |
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# os.setsid() |
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# This prevent the signal to be sent to the children (and create a new process group) |
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os.setpgrp() |
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# signal.signal(signal.SIGINT, signal.SIG_IGN) |
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class Processes (object): |
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# how many time can a process can respawn in the time interval |
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respawn_timemask = 0xFFFFFF - 0b111111 |
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# '0b111111111111111111000000' (around a minute, 63 seconds) |
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_dispatch = {} |
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def __init__ (self): |
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self.logger = Logger() |
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self.clean() |
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self.silence = False |
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self._buffer = {} |
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self._configuration = {} |
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self.respawn_number = 5 if environment.settings().api.respawn else 0 |
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self.terminate_on_error = environment.settings().api.terminate |
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self.ack = environment.settings().api.ack |
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def number (self): |
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return len(self._process) |
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def clean (self): |
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self.fds = [] |
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self._process = {} |
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self._encoder = {} |
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self._broken = [] |
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self._respawning = {} |
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def _handle_problem (self, process): |
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if process not in self._process: |
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return |
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if self.respawn_number: |
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self.logger.debug('issue with the process, restarting it','process') |
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self._terminate(process) |
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self._start(process) |
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else: |
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self.logger.debug('issue with the process, terminating it','process') |
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self._terminate(process) |
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def _terminate (self, process_name): |
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self.logger.debug('terminating process %s' % process_name, 'process') |
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process = self._process[process_name] |
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del self._process[process_name] |
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self._update_fds() |
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thread = Thread(target=self._terminate_run, args=(process,)) |
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thread.start() |
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return thread |
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def _terminate_run (self, process): |
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try: |
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process.terminate() |
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process.wait() |
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except (OSError, KeyError): |
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# the process is most likely already dead |
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pass |
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def terminate (self): |
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for process in list(self._process): |
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if not self.silence: |
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try: |
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self.write(process,self._encoder[process].shutdown()) |
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except ProcessError: |
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pass |
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self.silence = True |
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# waiting a little to make sure IO is flushed to the pipes |
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# we are using unbuffered IO but still .. |
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time.sleep(0.1) |
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for process in list(self._process): |
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try: |
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t = self._terminate(process) |
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t.join() |
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except OSError: |
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# we most likely received a SIGTERM signal and our child is already dead |
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self.logger.debug('child process %s was already dead' % process,'process') |
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self.clean() |
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def _start (self,process): |
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try: |
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if process in self._process: |
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self.logger.debug('process already running','process') |
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return |
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if process not in self._configuration: |
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self.logger.debug('can not start process, no configuration for it','process') |
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return |
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# Prevent some weird termcap data to be created at the start of the PIPE |
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# \x1b[?1034h (no-eol) (esc) |
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os.environ['TERM'] = 'dumb' |
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configuration = self._configuration[process] |
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run = configuration.get('run','') |
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if run: |
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api = configuration.get('encoder','') |
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self._encoder[process] = Response.Text(text_version) if api == 'text' else Response.JSON(json_version) |
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self._process[process] = subprocess.Popen( |
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run, |
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stdin=subprocess.PIPE, |
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stdout=subprocess.PIPE, |
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preexec_fn=preexec_helper |
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# This flags exists for python 2.7.3 in the documentation but on on my MAC |
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# creationflags=subprocess.CREATE_NEW_PROCESS_GROUP |
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) |
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self._update_fds() |
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fcntl.fcntl(self._process[process].stdout.fileno(), fcntl.F_SETFL, os.O_NONBLOCK) |
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self.logger.debug('forked process %s' % process,'process') |
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around_now = int(time.time()) & self.respawn_timemask |
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if process in self._respawning: |
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if around_now in self._respawning[process]: |
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self._respawning[process][around_now] += 1 |
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# we are respawning too fast |
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if self._respawning[process][around_now] > self.respawn_number: |
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self.logger.critical( |
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'Too many death for %s (%d) terminating program' % (process,self.respawn_number), |
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'process' |
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) |
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raise ProcessError() |
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else: |
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# reset long time since last respawn |
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self._respawning[process] = {around_now: 1} |
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else: |
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# record respawing |
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self._respawning[process] = {around_now: 1} |
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except (subprocess.CalledProcessError,OSError,ValueError) as exc: |
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self._broken.append(process) |
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self.logger.debug('could not start process %s' % process,'process') |
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self.logger.debug('reason: %s' % str(exc),'process') |
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def start (self, configuration, restart=False): |
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for process in list(self._process): |
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if process not in configuration: |
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self._terminate(process) |
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self._configuration = configuration |
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for process in configuration: |
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if restart and process in list(self._process): |
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self._terminate(process) |
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self._start(process) |
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def broken (self, neighbor): |
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if self._broken: |
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for process in self._configuration: |
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if process in self._broken: |
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return True |
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return False |
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def _update_fds (self): |
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self.fds = [self._process[process].stdout.fileno() for process in self._process] |
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def received (self): |
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consumed_data = False |
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for process in list(self._process): |
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try: |
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proc = self._process[process] |
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poll = proc.poll() |
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# proc.poll returns None if the process is still fine |
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# -[signal], like -15, if the process was terminated |
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if poll is not None: |
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self._handle_problem(process) |
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return |
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r,_,_ = select.select([proc.stdout,],[],[],0) |
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if not r: |
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continue |
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try: |
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# Calling next() on Linux and OSX works perfectly well |
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# but not on OpenBSD where it always raise StopIteration |
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# and only readline() works |
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buf = str_ascii(proc.stdout.read(16384)) |
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if buf == '' and poll is not None: |
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# if proc.poll() is None then |
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# process is fine, we received an empty line because |
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# we're doing .readline() on a non-blocking pipe and |
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# the process maybe has nothing to send yet |
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self._handle_problem(process) |
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continue |
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raw = self._buffer.get(process,'') + buf |
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while '\n' in raw: |
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line,raw = raw.split('\n',1) |
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line = line.rstrip() |
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consumed_data = True |
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self.logger.debug('command from process %s : %s ' % (process,line),'process') |
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yield (process,formated(line)) |
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self._buffer[process] = raw |
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except IOError as exc: |
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if not exc.errno or exc.errno in error.fatal: |
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# if the program exits we can get an IOError with errno code zero ! |
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self._handle_problem(process) |
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elif exc.errno in error.block: |
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# we often see errno.EINTR: call interrupted and |
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# we most likely have data, we will try to read them a the next loop iteration |
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pass |
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else: |
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self.logger.debug('unexpected errno received from forked process (%s)' % errstr(exc),'process') |
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except StopIteration: |
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if not consumed_data: |
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self._handle_problem(process) |
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except KeyError: |
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pass |
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except (subprocess.CalledProcessError,OSError,ValueError): |
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self._handle_problem(process) |
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def write (self, process, string, neighbor=None): |
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if string is None: |
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return True |
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260
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261
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# XXX: FIXME: This is potentially blocking |
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while True: |
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try: |
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264
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self._process[process].stdin.write(bytes_ascii('%s\n' % string)) |
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except IOError as exc: |
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self._broken.append(process) |
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267
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if exc.errno == errno.EPIPE: |
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268
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self._broken.append(process) |
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self.logger.debug('issue while sending data to our helper program','process') |
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270
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raise ProcessError() |
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else: |
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272
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# Could it have been caused by a signal ? What to do. |
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273
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self.logger.debug('error received while sending data to helper program, retrying (%s)' % errstr(exc),'process') |
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274
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continue |
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275
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break |
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276
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277
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try: |
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278
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self._process[process].stdin.flush() |
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279
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except IOError as exc: |
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280
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# AFAIK, the buffer should be flushed at the next attempt. |
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281
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self.logger.debug('error received while FLUSHING data to helper program, retrying (%s)' % errstr(exc),'process') |
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282
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283
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return True |
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284
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285
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def _answer (self, service, string, force=False): |
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286
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if force or self.ack: |
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287
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self.logger.debug('responding to %s : %s' % (service,string.replace('\n', '\\n')), 'process') |
|
288
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self.write(service,string) |
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289
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290
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def answer_done (self, service): |
|
291
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self._answer(service,Answer.done) |
|
292
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293
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def answer_error (self, service): |
|
294
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self._answer(service, Answer.error) |
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295
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296
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def _notify (self, neighbor, event): |
|
297
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for process in neighbor.api[event]: |
|
298
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yield process |
|
299
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300
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# do not do anything if silenced |
|
301
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# no-self-argument |
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302
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|
303
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def silenced (function): |
|
304
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def closure (self, *args): |
|
305
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if self.silence: |
|
306
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return |
|
307
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|
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return function(self,*args) |
|
308
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|
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return closure |
|
309
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|
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|
|
310
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|
|
# invalid-name |
|
311
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|
|
@silenced |
|
312
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|
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def up (self, neighbor): |
|
313
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|
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for process in self._notify(neighbor,'neighbor-changes'): |
|
314
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|
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self.write(process,self._encoder[process].up(neighbor),neighbor) |
|
315
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|
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|
|
316
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|
|
@silenced |
|
317
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|
|
def connected (self, neighbor): |
|
318
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|
|
for process in self._notify(neighbor,'neighbor-changes'): |
|
319
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|
|
self.write(process,self._encoder[process].connected(neighbor),neighbor) |
|
320
|
|
|
|
|
321
|
|
|
@silenced |
|
322
|
|
|
def down (self, neighbor, reason): |
|
323
|
|
|
for process in self._notify(neighbor,'neighbor-changes'): |
|
324
|
|
|
self.write(process,self._encoder[process].down(neighbor,reason),neighbor) |
|
325
|
|
|
|
|
326
|
|
|
@silenced |
|
327
|
|
|
def negotiated (self, neighbor, negotiated): |
|
328
|
|
|
for process in self._notify(neighbor,'negotiated'): |
|
329
|
|
|
self.write(process,self._encoder[process].negotiated(neighbor,negotiated),neighbor) |
|
330
|
|
|
|
|
331
|
|
|
@silenced |
|
332
|
|
|
def fsm (self, neighbor, fsm): |
|
333
|
|
|
for process in self._notify(neighbor,'fsm'): |
|
334
|
|
|
self.write(process,self._encoder[process].fsm(neighbor,fsm),neighbor) |
|
335
|
|
|
|
|
336
|
|
|
@silenced |
|
337
|
|
|
def signal (self, neighbor, signal): |
|
338
|
|
|
for process in self._notify(neighbor,'signal'): |
|
339
|
|
|
self.write(process,self._encoder[process].signal(neighbor,signal),neighbor) |
|
340
|
|
|
|
|
341
|
|
|
@silenced |
|
342
|
|
|
def packets (self, neighbor, direction, category, header, body): |
|
343
|
|
|
for process in self._notify(neighbor,'%s-packets' % direction): |
|
344
|
|
|
self.write(process,self._encoder[process].packets(neighbor,direction,category,header,body),neighbor) |
|
345
|
|
|
|
|
346
|
|
|
@silenced |
|
347
|
|
|
def notification (self, neighbor, direction, code, subcode, data, header, body): |
|
348
|
|
|
for process in self._notify(neighbor,'neighbor-changes'): |
|
349
|
|
|
self.write(process,self._encoder[process].notification(neighbor,direction,code,subcode,data,header,body),neighbor) |
|
350
|
|
|
|
|
351
|
|
|
@silenced |
|
352
|
|
|
def message (self, message_id, neighbor, direction, message, negotiated, header, *body): |
|
353
|
|
|
self._dispatch[message_id](self,neighbor,direction,message,negotiated,header,*body) |
|
354
|
|
|
|
|
355
|
|
|
# registering message functions |
|
356
|
|
|
# no-self-argument |
|
357
|
|
|
|
|
358
|
|
|
def register_process (message_id, storage=_dispatch): |
|
359
|
|
|
def closure (function): |
|
360
|
|
|
def wrap (*args): |
|
361
|
|
|
function(*args) |
|
362
|
|
|
storage[message_id] = wrap |
|
363
|
|
|
return wrap |
|
364
|
|
|
return closure |
|
365
|
|
|
|
|
366
|
|
|
# notifications are handled in the loop as they use different arguments |
|
367
|
|
|
|
|
368
|
|
|
@register_process(Message.CODE.OPEN) |
|
369
|
|
|
def _open (self, peer, direction, message, negotiated, header, body): |
|
370
|
|
|
for process in self._notify(peer,'%s-%s' % (direction,Message.CODE.OPEN.SHORT)): |
|
371
|
|
|
self.write(process,self._encoder[process].open(peer,direction,message,negotiated,header,body),peer) |
|
372
|
|
|
|
|
373
|
|
|
@register_process(Message.CODE.UPDATE) |
|
374
|
|
|
def _update (self, peer, direction, update, negotiated, header, body): |
|
375
|
|
|
for process in self._notify(peer,'%s-%s' % (direction,Message.CODE.UPDATE.SHORT)): |
|
376
|
|
|
self.write(process,self._encoder[process].update(peer,direction,update,negotiated,header,body),peer) |
|
377
|
|
|
|
|
378
|
|
|
@register_process(Message.CODE.NOTIFICATION) |
|
379
|
|
|
def _notification (self, peer, direction, message, negotiated, header, body): |
|
380
|
|
|
for process in self._notify(peer,'%s-%s' % (direction,Message.CODE.NOTIFICATION.SHORT)): |
|
381
|
|
|
self.write(process,self._encoder[process].notification(peer,direction,message,negotiated,header,body),peer) |
|
382
|
|
|
|
|
383
|
|
|
# unused-argument, must keep the API |
|
384
|
|
|
@register_process(Message.CODE.KEEPALIVE) |
|
385
|
|
|
def _keepalive (self, peer, direction, keepalive, negotiated, header, body): |
|
386
|
|
|
for process in self._notify(peer,'%s-%s' % (direction,Message.CODE.KEEPALIVE.SHORT)): |
|
387
|
|
|
self.write(process,self._encoder[process].keepalive(peer,direction,negotiated,header,body),peer) |
|
388
|
|
|
|
|
389
|
|
|
@register_process(Message.CODE.ROUTE_REFRESH) |
|
390
|
|
|
def _refresh (self, peer, direction, refresh, negotiated, header, body): |
|
391
|
|
|
for process in self._notify(peer,'%s-%s' % (direction,Message.CODE.ROUTE_REFRESH.SHORT)): |
|
392
|
|
|
self.write(process,self._encoder[process].refresh(peer,direction,refresh,negotiated,header,body),peer) |
|
393
|
|
|
|
|
394
|
|
|
@register_process(Message.CODE.OPERATIONAL) |
|
395
|
|
|
def _operational (self, peer, direction, operational, negotiated, header, body): |
|
396
|
|
|
for process in self._notify(peer,'%s-%s' % (direction,Message.CODE.OPERATIONAL.SHORT)): |
|
397
|
|
|
self.write(process,self._encoder[process].operational(peer,direction,operational.category,operational,negotiated,header,body),peer) |
|
398
|
|
|
|