/usr/lib/python2.7/dist-packages/twext/application/masterchild.py is in python-twext 0.1.b2.dev15059-1.
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# Copyright (c) 2013-2015 Apple Inc. All rights reserved.
#
# Licensed under the Apache License, Version 2.0 (the "License");
# you may not use this file except in compliance with the License.
# You may obtain a copy of the License at
#
# http://www.apache.org/licenses/LICENSE-2.0
#
# Unless required by applicable law or agreed to in writing, software
# distributed under the License is distributed on an "AS IS" BASIS,
# WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
# See the License for the specific language governing permissions and
# limitations under the License.
##
"""
Application container for a service consisting of a master process that
accepts connections and dispatches them via inherited file descriptors to
child processes.
"""
# python -c 'from twisted.scripts.twistd import run; run()' \
# -n -l - master --protocol=twext.protocols.echo.EchoProtocol --port=8080
from __future__ import print_function
__all__ = [
"MasterOptions",
"MasterServiceMaker",
"ChildOptions",
"ChildServiceMaker",
]
import sys
from os import close, unlink
from tempfile import mkstemp
from zope.interface import implementer
from twisted.python.sendmsg import getsockfam
from twisted.python.usage import Options, UsageError
from twisted.python.reflect import namedClass
from twisted.python.util import FancyStrMixin
from twisted.application.service import MultiService, Service
from twisted.application.service import IServiceMaker
from twisted.application.internet import TCPServer
from twisted.protocols.policies import WrappingFactory, ProtocolWrapper
from twisted.internet.protocol import Protocol
from twisted.internet.protocol import ServerFactory
from twisted.internet.protocol import ProcessProtocol
from twext.python.log import Logger
from twext.internet.sendfdport import InheritingProtocolFactory, IStatus
from twext.internet.sendfdport import InheritedSocketDispatcher
from twext.internet.sendfdport import IStatusWatcher
from twext.internet.sendfdport import InheritedPort
class MasterOptions(Options):
"""
Options for a master process.
"""
def opt_protocol(self, value):
"""
Protocol and port (specify as proto:port).
"""
try:
protocol, port = value.split(":")
except ValueError:
if ":" in value:
raise UsageError("Invalid protocol argument.")
else:
raise UsageError("Port is required in protocol argument.")
# Validate protocol name
try:
protocolClass = namedClass(protocol)
except (ValueError, AttributeError):
raise UsageError("Unknown protocol: {0}".format(protocol))
try:
if not issubclass(protocolClass, Protocol):
raise TypeError()
except TypeError:
raise UsageError("Not a protocol: {0}".format(protocol))
# FIXME: port should be a strport
# Validate port number
try:
try:
port = int(port)
except ValueError:
raise ValueError("not an integer")
if port < 0:
raise ValueError("must be >=0")
except ValueError as e:
raise UsageError(
"Invalid port number {0}: {1}".format(port, e)
)
protocols = self.setdefault("protocols", [])
for (otherProtocol, otherPort) in protocols:
# FIXME: Raise here because we don't properly handle multiple
# protocols yet.
raise UsageError("Only one protocol may be specified.")
if otherPort == port:
if otherProtocol == protocol:
return
raise UsageError(
"Port {0} cannot be registered more than once "
"for different protocols: ({1}, {2})",
otherProtocol, protocol
)
protocols.append((protocol, port))
def postOptions(self):
for (parameter, key) in [("protocol", "protocols")]:
if key not in self:
raise UsageError("{0} parameter is required".format(parameter))
class SpawningInheritingProtocolFactory(InheritingProtocolFactory):
"""
Protocol factory for a spawning service.
"""
def __init__(self, dispatcher, spawningService, description):
super(SpawningInheritingProtocolFactory, self).__init__(
dispatcher, description
)
self.spawningService = spawningService
def sendSocket(self, socketObject):
self.spawningService.socketWillArriveForProtocol(self.description)
super(SpawningInheritingProtocolFactory, self).sendSocket(socketObject)
@implementer(IStatusWatcher)
class MasterService(MultiService, object):
"""
Service for master processes.
"""
log = Logger()
def __init__(self):
MultiService.__init__(self)
# Dispatcher
self.dispatcher = InheritedSocketDispatcher(self)
# Child Processes
self.log.info("Setting up master/child spawning service...")
self.spawningService = ChildSpawningService(self.dispatcher)
self.spawningService.setServiceParent(self)
def addProtocol(self, protocol, port):
self.log.info(
"Setting service for protocol {protocol!r} on port {port}...",
protocol=protocol, port=port,
)
# TCP Service
tcpFactory = SpawningInheritingProtocolFactory(
self.dispatcher, self.spawningService, protocol
)
tcpService = TCPServer(port, tcpFactory)
tcpService.setServiceParent(self)
def startService(self):
"""
Start up multiservice, then start up the dispatcher.
"""
super(MasterService, self).startService()
self.dispatcher.startDispatching()
# IStatusWatcher
@staticmethod
def initialStatus():
return ChildStatus()
@staticmethod
def newConnectionStatus(previousStatus):
"""
A connection was just sent to the process, but not yet acknowledged.
"""
return previousStatus.adjust(unacknowledged=1)
@staticmethod
def statusFromMessage(previousStatus, message):
if message == "-":
# A connection has gone away in a subprocess; we should start
# accepting connections again if we paused (see
# newConnectionStatus)
return previousStatus.adjust(acknowledged=-1)
elif message == "0":
# A new process just started accepting new connections.
return previousStatus.restarted()
elif message == "+":
# Acknowledges that the subprocess has taken on the work.
return previousStatus.adjust(
acknowledged=1,
unacknowledged=-1,
total=1,
unclosed=1,
)
else:
raise AssertionError("Unknown message: {0}".format(message))
@staticmethod
def closeCountFromStatus(previousStatus):
toClose = previousStatus.unclosed
return (toClose, previousStatus.adjust(unclosed=-toClose))
def statusesChanged(self, statuses):
# FIXME: This isn't in IStatusWatcher, but is called by
# InheritedSocketDispatcher.
self.log.info("Status changed: {0}".format(tuple(statuses)))
# current = sum(status.effective()
# for status in self.dispatcher.statuses)
# self._outstandingRequests = current # preserve for or= field in log
# maximum = self.maxRequests
# overloaded = (current >= maximum)
# available = len(filter(lambda x: x.active(), self.dispatcher.statuses))
# self.overloaded = (overloaded or available == 0)
# for f in self.factories:
# if self.overloaded:
# f.loadAboveMaximum()
# else:
# f.loadNominal()
@implementer(IServiceMaker)
class MasterServiceMaker(object):
"""
Master process service maker.
"""
log = Logger()
def __init__(self):
self.tapname = "master"
self.description = self.__class__.__doc__
self.options = MasterOptions
def makeService(self, options):
service = MasterService()
for protocol, port in options["protocols"]:
service.addProtocol(protocol, port)
return service
class ChildProcess(object):
"""
Child process.
"""
def __init__(self, transport, protocol):
self.transport = transport
self.protocol = protocol
class ChildSpawningService(Service, object):
"""
Service that spawns children as necessary.
"""
log = Logger()
pluginName = b"child"
def __init__(
self, dispatcher, maxProcessCount=8, highWaterMark=3
):
"""
@param dispatcher: The dispatcher managing inbound connections.
@type dispatcher: L{InheritedSocketDispatcher}
@param maxProcessCount: The maximum number of child processes that may
be spawned.
@type maxProcessCount: L{int}
@param highWaterMark: The high-end number of connections that each
process should be given before new processes should be spawned.
@type highWaterMark: L{int}
"""
self.dispatcher = dispatcher
self.maxProcessCount = maxProcessCount
self.highWaterMark = highWaterMark
def startService(self):
assert not hasattr(self, "children")
self.children = set()
def stopService(self):
del(self.children)
def totalEffectiveLoad(self):
"""
Compute the sum of the effective load of all child process.
@return: The total effective load accross all processes.
@rtype: L{float}
"""
return sum(s.effectiveLoad() for s in self.dispatcher.statuses)
def socketWillArriveForProtocol(self, protocolName):
"""
This method is where this service makes sure that there are
sufficient child processes available to handle additional
connections.
"""
numChildren = len(self.children)
if numChildren == 0:
self.log.info("Spawning first child.")
self.spawnChild(protocolName)
return
totalLoad = self.totalEffectiveLoad()
averageLoad = float(totalLoad) / float(numChildren)
# self.log.info(
# "Load: {totalLoad} / {childCount} = {averageLoad}",
# totalLoad=totalLoad,
# childCount=numChildren,
# averageLoad=averageLoad,
# )
if averageLoad >= self.highWaterMark:
if numChildren < self.maxProcessCount:
self.spawnChild(protocolName)
def spawnChild(self, protocolName):
"""
Spawn a child process to handle connections.
"""
from twisted.internet import reactor
inheritedSocket = self.dispatcher.addSocket()
inheritedFD = inheritedSocket.childSocket().fileno()
processProtocol = ChildProcessProtocol(self, inheritedSocket)
# Annoyingly, twistd *has* to make a pid file.
pidFileFD, pidFileName = mkstemp()
close(pidFileFD)
unlink(pidFileName)
arguments = (
sys.executable, b"-c",
b"from twisted.scripts.twistd import run; run()",
b"--pidfile", pidFileName,
b"--nodaemon", b"--logfile", b"-",
self.pluginName,
b"--inherited-fd=3",
b"--protocol", protocolName,
)
self.log.debug(
u"Spawning child process for protocol {protocol!r} "
u"with arguments: {arguments}",
protocol=protocolName, arguments=arguments,
)
transport = reactor.spawnProcess(
processProtocol,
sys.executable, arguments, env={
b"PYTHONPATH": b":".join(sys.path),
},
childFDs={0: b"w", 1: b"r", 2: b"r", 3: inheritedFD}
)
child = ChildProcess(transport, processProtocol)
self.log.info(
u"Spawned child process #{child.transport.pid} "
u"for protocol {protocol!r}",
child=child, protocol=protocolName, arguments=arguments,
)
self.children.add(child)
def childDidExit(self, processProtocol, reason):
"""
Called by L{ChildProcessProtocol} to alert this service that a
child process has exited.
@param processProtocol: The processProtocol for the child that
exited.
@type processProtocol: L{ChildProcessProtocol}
@param reason: The reason that the child exited.
@type reason: L{Failure}
"""
for child in self.children:
if child.protocol == processProtocol:
self.log.info(
u"Child process ({child.transport.pid}) exited: "
u"{reason}",
child=child, reason=reason,
)
self.children.remove(child)
break
else:
self.log.error(
u"No child for for process protocol",
processProtocol=processProtocol
)
try:
self.dispatcher.removeSocket(processProtocol.inheritedSocket)
except ValueError:
self.log.error(
u"No socket found for process protocol",
processProtocol=processProtocol
)
class ChildProcessProtocol(ProcessProtocol, object):
"""
Process protocol for child processes.
"""
# FIXME: deserialize log events from child
# log = Logger()
def __init__(self, service, inheritedSocket):
self.service = service
self.inheritedSocket = inheritedSocket
# Always tell any metafd socket that we have started, so it can
# re-initialize state.
self.inheritedSocket.start()
def outReceived(self, data):
# self.log.info(u"{data}", data=data)
sys.stdout.write(data)
def errReceived(self, data):
super(ChildProcessProtocol, self).errReceived(data)
# self.log.error(u"{data}", data=data)
sys.stderr.write(data)
def processExited(self, reason):
# Always tell any metafd socket that we have started, so it can
# re-initialize state.
self.inheritedSocket.stop()
self.service.childDidExit(self, reason)
class ChildOptions(Options):
"""
Options for a child process.
"""
def opt_protocol(self, value):
"""
Protocol
"""
try:
protocol = namedClass(value)
except (ValueError, AttributeError):
raise UsageError("Unknown protocol: {0}".format(value))
self["protocol"] = protocol
def opt_inherited_fd(self, value):
"""
Inherited file descriptor
"""
try:
try:
fd = int(value)
except ValueError:
raise ValueError("not an integer")
if fd < 0:
raise ValueError("must be >=0")
except ValueError as e:
raise UsageError(
"Invalid file descriptor {0!r}: {1}".format(value, e)
)
self["inherited-fd"] = fd
def postOptions(self):
for parameter in ("protocol", "inherited-fd"):
if parameter not in self:
raise UsageError("{0} parameter is required".format(parameter))
@implementer(IServiceMaker)
class ChildServiceMaker(object):
"""
Child process service maker.
"""
def __init__(self):
self.tapname = "child"
self.description = self.__class__.__doc__
self.options = ChildOptions
def makeService(self, options):
factory = ServerFactory.forProtocol(options["protocol"])
service = ChildService(options["inherited-fd"], factory)
return service
class ChildService(Service, object):
"""
Service for child processes.
"""
log = Logger()
def __init__(self, fd, protocolFactory):
self.fd = fd
self.protocolFactory = protocolFactory
def startService(self):
factory = ReportingWrapperFactory(
self.protocolFactory, self.fd, self.createTransport
)
self.wrappedProtocolFactory = factory
factory.inheritedPort.startReading()
factory.inheritedPort.reportStatus("0")
return super(ChildService, self).startService()
def stopService(self):
factory = self.wrappedProtocolFactory
# Halt connection inflow
factory.inheritedPort.stopReading()
# Wait for existing connections to close
factory.allConnectionsClosed()
return super(ChildService, self).stopService()
def createTransport(self, socket, peer, data, protocol):
"""
Create a TCP transport from a socket object passed by the parent.
"""
from twisted.internet import reactor
factory = self.wrappedProtocolFactory
factory.inheritedPort.reportStatus("+")
self.log.info("{factory.inheritedPort.statusQueue}", factory=factory)
socketFD = socket.fileno()
transport = reactor.adoptStreamConnection(
socketFD, getsockfam(socketFD), factory
)
transport.startReading()
return transport
class ReportingProtocolWrapper(ProtocolWrapper, object):
def __init__(self, *args, **kwargs):
try:
raise RuntimeError()
except RuntimeError:
from twisted.python.failure import Failure
f = Failure()
f.printTraceback()
return super(ReportingProtocolWrapper, self).__init__(
*args, **kwargs
)
def connectionLost(self, reason):
# self.factory.protocolDidLoseConnection(self)
self.factory.inheritedPort.reportStatus("-")
return super(ReportingProtocolWrapper, self).connectionLost(reason)
class ReportingWrapperFactory(WrappingFactory, object):
log = Logger()
protocol = ReportingProtocolWrapper
def __init__(self, wrappedFactory, fd, createTransport):
self.inheritedPort = InheritedPort(fd, createTransport, self)
super(ReportingWrapperFactory, self).__init__(wrappedFactory)
def registerProtocol(self, p):
super(ReportingWrapperFactory, self).registerProtocol(p)
self.log.info(
"++++ Registered protocol: {protocol}\n"
"Remaining protocols: {factory.protocols}",
factory=self, protocol=p
)
def unregisterProtocol(self, p):
super(ReportingWrapperFactory, self).unregisterProtocol(p)
self.log.info(
"---- Unregistered protocol: {protocol}\n"
"Remaining protocols: {factory.protocols}",
factory=self, protocol=p
)
@implementer(IStatus)
class ChildStatus(FancyStrMixin, object):
"""
The status of a child process.
"""
showAttributes = (
"acknowledged",
"unacknowledged",
"total",
"started",
"abandoned",
"unclosed",
"starting",
"stopped",
)
def __init__(
self,
acknowledged=0,
unacknowledged=0,
total=0,
started=0,
abandoned=0,
unclosed=0,
starting=0,
stopped=0
):
"""
Create a L{ConnectionStatus} with a number of sent connections and a
number of un-acknowledged connections.
@param acknowledged: the number of connections which we know the
subprocess to be presently processing; i.e. those which have been
transmitted to the subprocess.
@param unacknowledged: The number of connections which we have sent to
the subprocess which have never received a status response (a
"C{+}" status message).
@param total: The total number of acknowledged connections over
the lifetime of this socket.
@param started: The number of times this worker has been started.
@param abandoned: The number of connections which have been sent to
this worker, but were not acknowledged at the moment that the
worker was stopped.
@param unclosed: The number of sockets which have been sent to the
subprocess but not yet closed.
@param starting: The process that owns this socket is starting. Do not
dispatch to it until we receive the started message.
@param stopped: The process that owns this socket has stopped. Do not
dispatch to it.
"""
self.acknowledged = acknowledged
self.unacknowledged = unacknowledged
self.total = total
self.started = started
self.abandoned = abandoned
self.unclosed = unclosed
self.starting = starting
self.stopped = stopped
def effectiveLoad(self):
"""
The current effective load.
"""
return self.acknowledged + self.unacknowledged
def active(self):
"""
Is the subprocess associated with this socket available to dispatch to.
i.e, this socket is neither stopped nor starting
"""
return self.starting == 0 and self.stopped == 0
def start(self):
"""
The child process for this L{WorkerStatus} is about to (re)start.
Reset the status to indicate it is starting - that should prevent any
new connections being dispatched.
"""
return self.reset(
starting=1,
stopped=0,
)
def restarted(self):
"""
The child process for this L{WorkerStatus} has indicated it is now
available to accept connections, so reset the starting status so this
socket will be available for dispatch.
"""
return self.reset(
started=self.started + 1,
starting=0,
)
def stop(self):
"""
The child process for this L{WorkerStatus} has stopped. Stop the socket
and clear out existing counters, but track abandoned connections.
"""
return self.reset(
acknowledged=0,
unacknowledged=0,
abandoned=self.abandoned + self.unacknowledged,
starting=0,
stopped=1,
)
def adjust(self, **kwargs):
"""
Update the L{WorkerStatus} by adding the supplied values to the
specified attributes.
"""
for k, v in kwargs.items():
newval = getattr(self, k) + v
setattr(self, k, max(newval, 0))
return self
def reset(self, **kwargs):
"""
Reset the L{WorkerStatus} by setting the supplied values in the
specified attributes.
"""
for k, v in kwargs.items():
setattr(self, k, v)
return self
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