461 lines
		
	
	
		
			15 KiB
		
	
	
	
		
			Python
		
	
	
			
		
		
	
	
			461 lines
		
	
	
		
			15 KiB
		
	
	
	
		
			Python
		
	
	
| # -*- coding: utf-8 -*-
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| # Copyright 2017 New Vector Ltd
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| #
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| # Licensed under the Apache License, Version 2.0 (the "License");
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| # you may not use this file except in compliance with the License.
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| # You may obtain a copy of the License at
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| #
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| #     http://www.apache.org/licenses/LICENSE-2.0
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| #
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| # Unless required by applicable law or agreed to in writing, software
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| # distributed under the License is distributed on an "AS IS" BASIS,
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| # WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
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| # See the License for the specific language governing permissions and
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| # limitations under the License.
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| 
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| import gc
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| import logging
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| import os
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| import signal
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| import socket
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| import sys
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| import traceback
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| 
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| from daemonize import Daemonize
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| 
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| from twisted.internet import defer, error, reactor
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| from twisted.protocols.tls import TLSMemoryBIOFactory
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| 
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| import synapse
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| from synapse.app import check_bind_error
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| from synapse.crypto import context_factory
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| from synapse.logging.context import PreserveLoggingContext
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| from synapse.util.async_helpers import Linearizer
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| from synapse.util.rlimit import change_resource_limit
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| from synapse.util.versionstring import get_version_string
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| 
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| logger = logging.getLogger(__name__)
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| 
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| # list of tuples of function, args list, kwargs dict
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| _sighup_callbacks = []
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| 
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| 
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| def register_sighup(func, *args, **kwargs):
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|     """
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|     Register a function to be called when a SIGHUP occurs.
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| 
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|     Args:
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|         func (function): Function to be called when sent a SIGHUP signal.
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|             Will be called with a single default argument, the homeserver.
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|         *args, **kwargs: args and kwargs to be passed to the target function.
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|     """
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|     _sighup_callbacks.append((func, args, kwargs))
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| 
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| 
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| def start_worker_reactor(appname, config, run_command=reactor.run):
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|     """ Run the reactor in the main process
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| 
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|     Daemonizes if necessary, and then configures some resources, before starting
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|     the reactor. Pulls configuration from the 'worker' settings in 'config'.
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| 
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|     Args:
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|         appname (str): application name which will be sent to syslog
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|         config (synapse.config.Config): config object
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|         run_command (Callable[]): callable that actually runs the reactor
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|     """
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| 
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|     logger = logging.getLogger(config.worker_app)
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| 
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|     start_reactor(
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|         appname,
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|         soft_file_limit=config.soft_file_limit,
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|         gc_thresholds=config.gc_thresholds,
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|         pid_file=config.worker_pid_file,
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|         daemonize=config.worker_daemonize,
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|         print_pidfile=config.print_pidfile,
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|         logger=logger,
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|         run_command=run_command,
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|     )
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| 
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| 
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| def start_reactor(
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|     appname,
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|     soft_file_limit,
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|     gc_thresholds,
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|     pid_file,
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|     daemonize,
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|     print_pidfile,
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|     logger,
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|     run_command=reactor.run,
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| ):
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|     """ Run the reactor in the main process
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| 
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|     Daemonizes if necessary, and then configures some resources, before starting
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|     the reactor
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| 
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|     Args:
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|         appname (str): application name which will be sent to syslog
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|         soft_file_limit (int):
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|         gc_thresholds:
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|         pid_file (str): name of pid file to write to if daemonize is True
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|         daemonize (bool): true to run the reactor in a background process
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|         print_pidfile (bool): whether to print the pid file, if daemonize is True
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|         logger (logging.Logger): logger instance to pass to Daemonize
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|         run_command (Callable[]): callable that actually runs the reactor
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|     """
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| 
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|     install_dns_limiter(reactor)
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| 
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|     def run():
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|         logger.info("Running")
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|         change_resource_limit(soft_file_limit)
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|         if gc_thresholds:
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|             gc.set_threshold(*gc_thresholds)
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|         run_command()
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| 
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|     # make sure that we run the reactor with the sentinel log context,
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|     # otherwise other PreserveLoggingContext instances will get confused
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|     # and complain when they see the logcontext arbitrarily swapping
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|     # between the sentinel and `run` logcontexts.
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|     #
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|     # We also need to drop the logcontext before forking if we're daemonizing,
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|     # otherwise the cputime metrics get confused about the per-thread resource usage
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|     # appearing to go backwards.
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|     with PreserveLoggingContext():
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|         if daemonize:
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|             if print_pidfile:
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|                 print(pid_file)
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| 
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|             daemon = Daemonize(
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|                 app=appname,
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|                 pid=pid_file,
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|                 action=run,
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|                 auto_close_fds=False,
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|                 verbose=True,
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|                 logger=logger,
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|             )
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|             daemon.start()
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|         else:
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|             run()
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| 
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| 
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| def quit_with_error(error_string):
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|     message_lines = error_string.split("\n")
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|     line_length = max(len(l) for l in message_lines if len(l) < 80) + 2
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|     sys.stderr.write("*" * line_length + "\n")
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|     for line in message_lines:
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|         sys.stderr.write(" %s\n" % (line.rstrip(),))
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|     sys.stderr.write("*" * line_length + "\n")
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|     sys.exit(1)
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| 
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| 
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| def listen_metrics(bind_addresses, port):
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|     """
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|     Start Prometheus metrics server.
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|     """
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|     from synapse.metrics import RegistryProxy, start_http_server
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| 
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|     for host in bind_addresses:
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|         logger.info("Starting metrics listener on %s:%d", host, port)
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|         start_http_server(port, addr=host, registry=RegistryProxy)
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| 
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| 
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| def listen_tcp(bind_addresses, port, factory, reactor=reactor, backlog=50):
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|     """
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|     Create a TCP socket for a port and several addresses
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| 
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|     Returns:
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|         list[twisted.internet.tcp.Port]: listening for TCP connections
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|     """
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|     r = []
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|     for address in bind_addresses:
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|         try:
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|             r.append(reactor.listenTCP(port, factory, backlog, address))
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|         except error.CannotListenError as e:
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|             check_bind_error(e, address, bind_addresses)
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| 
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|     return r
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| 
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| 
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| def listen_ssl(
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|     bind_addresses, port, factory, context_factory, reactor=reactor, backlog=50
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| ):
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|     """
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|     Create an TLS-over-TCP socket for a port and several addresses
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| 
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|     Returns:
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|         list of twisted.internet.tcp.Port listening for TLS connections
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|     """
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|     r = []
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|     for address in bind_addresses:
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|         try:
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|             r.append(
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|                 reactor.listenSSL(port, factory, context_factory, backlog, address)
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|             )
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|         except error.CannotListenError as e:
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|             check_bind_error(e, address, bind_addresses)
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| 
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|     return r
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| 
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| 
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| def refresh_certificate(hs):
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|     """
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|     Refresh the TLS certificates that Synapse is using by re-reading them from
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|     disk and updating the TLS context factories to use them.
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|     """
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| 
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|     if not hs.config.has_tls_listener():
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|         # attempt to reload the certs for the good of the tls_fingerprints
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|         hs.config.read_certificate_from_disk(require_cert_and_key=False)
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|         return
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| 
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|     hs.config.read_certificate_from_disk(require_cert_and_key=True)
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|     hs.tls_server_context_factory = context_factory.ServerContextFactory(hs.config)
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| 
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|     if hs._listening_services:
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|         logger.info("Updating context factories...")
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|         for i in hs._listening_services:
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|             # When you listenSSL, it doesn't make an SSL port but a TCP one with
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|             # a TLS wrapping factory around the factory you actually want to get
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|             # requests. This factory attribute is public but missing from
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|             # Twisted's documentation.
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|             if isinstance(i.factory, TLSMemoryBIOFactory):
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|                 addr = i.getHost()
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|                 logger.info(
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|                     "Replacing TLS context factory on [%s]:%i", addr.host, addr.port
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|                 )
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|                 # We want to replace TLS factories with a new one, with the new
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|                 # TLS configuration. We do this by reaching in and pulling out
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|                 # the wrappedFactory, and then re-wrapping it.
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|                 i.factory = TLSMemoryBIOFactory(
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|                     hs.tls_server_context_factory, False, i.factory.wrappedFactory
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|                 )
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|         logger.info("Context factories updated.")
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| 
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| 
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| def start(hs, listeners=None):
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|     """
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|     Start a Synapse server or worker.
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| 
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|     Should be called once the reactor is running and (if we're using ACME) the
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|     TLS certificates are in place.
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| 
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|     Will start the main HTTP listeners and do some other startup tasks, and then
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|     notify systemd.
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| 
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|     Args:
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|         hs (synapse.server.HomeServer)
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|         listeners (list[dict]): Listener configuration ('listeners' in homeserver.yaml)
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|     """
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|     try:
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|         # Set up the SIGHUP machinery.
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|         if hasattr(signal, "SIGHUP"):
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| 
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|             def handle_sighup(*args, **kwargs):
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|                 # Tell systemd our state, if we're using it. This will silently fail if
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|                 # we're not using systemd.
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|                 sdnotify(b"RELOADING=1")
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| 
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|                 for i, args, kwargs in _sighup_callbacks:
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|                     i(hs, *args, **kwargs)
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| 
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|                 sdnotify(b"READY=1")
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| 
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|             signal.signal(signal.SIGHUP, handle_sighup)
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| 
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|             register_sighup(refresh_certificate)
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| 
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|         # Load the certificate from disk.
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|         refresh_certificate(hs)
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| 
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|         # Start the tracer
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|         synapse.logging.opentracing.init_tracer(  # type: ignore[attr-defined] # noqa
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|             hs.config
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|         )
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| 
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|         # It is now safe to start your Synapse.
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|         hs.start_listening(listeners)
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|         hs.get_datastore().db.start_profiling()
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| 
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|         setup_sentry(hs)
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|         setup_sdnotify(hs)
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| 
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|         # We now freeze all allocated objects in the hopes that (almost)
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|         # everything currently allocated are things that will be used for the
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|         # rest of time. Doing so means less work each GC (hopefully).
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|         #
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|         # This only works on Python 3.7
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|         if sys.version_info >= (3, 7):
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|             gc.collect()
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|             gc.freeze()
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|     except Exception:
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|         traceback.print_exc(file=sys.stderr)
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|         reactor = hs.get_reactor()
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|         if reactor.running:
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|             reactor.stop()
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|         sys.exit(1)
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| 
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| 
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| def setup_sentry(hs):
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|     """Enable sentry integration, if enabled in configuration
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| 
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|     Args:
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|         hs (synapse.server.HomeServer)
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|     """
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| 
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|     if not hs.config.sentry_enabled:
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|         return
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| 
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|     import sentry_sdk
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| 
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|     sentry_sdk.init(dsn=hs.config.sentry_dsn, release=get_version_string(synapse))
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| 
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|     # We set some default tags that give some context to this instance
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|     with sentry_sdk.configure_scope() as scope:
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|         scope.set_tag("matrix_server_name", hs.config.server_name)
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| 
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|         app = hs.config.worker_app if hs.config.worker_app else "synapse.app.homeserver"
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|         name = hs.config.worker_name if hs.config.worker_name else "master"
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|         scope.set_tag("worker_app", app)
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|         scope.set_tag("worker_name", name)
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| 
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| 
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| def setup_sdnotify(hs):
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|     """Adds process state hooks to tell systemd what we are up to.
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|     """
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| 
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|     # Tell systemd our state, if we're using it. This will silently fail if
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|     # we're not using systemd.
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|     sdnotify(b"READY=1\nMAINPID=%i" % (os.getpid(),))
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| 
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|     hs.get_reactor().addSystemEventTrigger(
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|         "before", "shutdown", sdnotify, b"STOPPING=1"
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|     )
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| 
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| 
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| def install_dns_limiter(reactor, max_dns_requests_in_flight=100):
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|     """Replaces the resolver with one that limits the number of in flight DNS
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|     requests.
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| 
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|     This is to workaround https://twistedmatrix.com/trac/ticket/9620, where we
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|     can run out of file descriptors and infinite loop if we attempt to do too
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|     many DNS queries at once
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|     """
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|     new_resolver = _LimitedHostnameResolver(
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|         reactor.nameResolver, max_dns_requests_in_flight
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|     )
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| 
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|     reactor.installNameResolver(new_resolver)
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| 
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| 
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| class _LimitedHostnameResolver(object):
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|     """Wraps a IHostnameResolver, limiting the number of in-flight DNS lookups.
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|     """
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| 
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|     def __init__(self, resolver, max_dns_requests_in_flight):
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|         self._resolver = resolver
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|         self._limiter = Linearizer(
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|             name="dns_client_limiter", max_count=max_dns_requests_in_flight
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|         )
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| 
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|     def resolveHostName(
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|         self,
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|         resolutionReceiver,
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|         hostName,
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|         portNumber=0,
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|         addressTypes=None,
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|         transportSemantics="TCP",
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|     ):
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|         # We need this function to return `resolutionReceiver` so we do all the
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|         # actual logic involving deferreds in a separate function.
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| 
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|         # even though this is happening within the depths of twisted, we need to drop
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|         # our logcontext before starting _resolve, otherwise: (a) _resolve will drop
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|         # the logcontext if it returns an incomplete deferred; (b) _resolve will
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|         # call the resolutionReceiver *with* a logcontext, which it won't be expecting.
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|         with PreserveLoggingContext():
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|             self._resolve(
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|                 resolutionReceiver,
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|                 hostName,
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|                 portNumber,
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|                 addressTypes,
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|                 transportSemantics,
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|             )
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| 
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|         return resolutionReceiver
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| 
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|     @defer.inlineCallbacks
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|     def _resolve(
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|         self,
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|         resolutionReceiver,
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|         hostName,
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|         portNumber=0,
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|         addressTypes=None,
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|         transportSemantics="TCP",
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|     ):
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| 
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|         with (yield self._limiter.queue(())):
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|             # resolveHostName doesn't return a Deferred, so we need to hook into
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|             # the receiver interface to get told when resolution has finished.
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| 
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|             deferred = defer.Deferred()
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|             receiver = _DeferredResolutionReceiver(resolutionReceiver, deferred)
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| 
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|             self._resolver.resolveHostName(
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|                 receiver, hostName, portNumber, addressTypes, transportSemantics
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|             )
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| 
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|             yield deferred
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| 
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| 
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| class _DeferredResolutionReceiver(object):
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|     """Wraps a IResolutionReceiver and simply resolves the given deferred when
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|     resolution is complete
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|     """
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| 
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|     def __init__(self, receiver, deferred):
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|         self._receiver = receiver
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|         self._deferred = deferred
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| 
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|     def resolutionBegan(self, resolutionInProgress):
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|         self._receiver.resolutionBegan(resolutionInProgress)
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| 
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|     def addressResolved(self, address):
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|         self._receiver.addressResolved(address)
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| 
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|     def resolutionComplete(self):
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|         self._deferred.callback(())
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|         self._receiver.resolutionComplete()
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| 
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| 
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| sdnotify_sockaddr = os.getenv("NOTIFY_SOCKET")
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| 
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| 
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| def sdnotify(state):
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|     """
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|     Send a notification to systemd, if the NOTIFY_SOCKET env var is set.
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| 
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|     This function is based on the sdnotify python package, but since it's only a few
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|     lines of code, it's easier to duplicate it here than to add a dependency on a
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|     package which many OSes don't include as a matter of principle.
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| 
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|     Args:
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|         state (bytes): notification to send
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|     """
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|     if not isinstance(state, bytes):
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|         raise TypeError("sdnotify should be called with a bytes")
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|     if not sdnotify_sockaddr:
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|         return
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|     addr = sdnotify_sockaddr
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|     if addr[0] == "@":
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|         addr = "\0" + addr[1:]
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| 
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|     try:
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|         with socket.socket(socket.AF_UNIX, socket.SOCK_DGRAM) as sock:
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|             sock.connect(addr)
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|             sock.sendall(state)
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|     except Exception as e:
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|         # this is a bit surprising, since we don't expect to have a NOTIFY_SOCKET
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|         # unless systemd is expecting us to notify it.
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|         logger.warning("Unable to send notification to systemd: %s", e)
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