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# Copyright 2015 The Chromium Authors. All rights reserved.
# Use of this source code is governed by a BSD-style license that can be
# found in the LICENSE file.
"""Defines the task RPC methods."""
import os
import sys
import logging
import threading
#pylint: disable=relative-import
import common_lib
# Map swarming_client to use subprocess42
sys.path.append(common_lib.SWARMING_DIR)
from utils import subprocess42
class RPCMethods(object):
"""Class exposing RPC methods."""
_dotted_whitelist = ['subprocess']
def __init__(self, server):
self._server = server
self.subprocess = Subprocess
def _dispatch(self, method, params):
obj = self
if '.' in method:
# Allow only white listed dotted names
name, method = method.split('.')
assert name in self._dotted_whitelist
obj = getattr(self, name)
return getattr(obj, method)(*params)
def Echo(self, message):
"""Simple RPC method to print and return a message."""
logging.info('Echoing %s', message)
return 'echo %s' % str(message)
def Quit(self):
"""Call _server.shutdown in another thread.
This is needed because server.shutdown waits for the server to actually
quit. However the server cannot shutdown until it completes handling this
call. Calling this in the same thread results in a deadlock.
"""
t = threading.Thread(target=self._server.shutdown)
t.start()
class Subprocess(object):
"""Implements a server-based non-blocking subprocess.
This non-blocking subprocess allows the caller to continue operating while
also able to interact with this subprocess based on a key returned to
the caller at the time of creation.
"""
_processes = {}
_process_next_id = 0
_creation_lock = threading.Lock()
def __init__(self, cmd):
self.proc = subprocess42.Popen(cmd, stdout=subprocess42.PIPE,
stderr=subprocess42.PIPE)
self.stdout = ''
self.stderr = ''
self.data_lock = threading.Lock()
threading.Thread(target=self._run).start()
def _run(self):
for pipe, data in self.proc.yield_any():
with self.data_lock:
if pipe == 'stdout':
self.stdout += data
else:
self.stderr += data
@classmethod
def Popen(cls, cmd):
with cls._creation_lock:
key = 'Process%d' % cls._process_next_id
cls._process_next_id += 1
logging.debug('Creating process %s', key)
process = cls(cmd)
cls._processes[key] = process
return key
@classmethod
def Terminate(cls, key):
logging.debug('Terminating and deleting process %s', key)
return cls._processes.pop(key).proc.terminate()
@classmethod
def Kill(cls, key):
logging.debug('Killing and deleting process %s', key)
return cls._processes.pop(key).proc.kill()
@classmethod
def Delete(cls, key):
logging.debug('Deleting process %s', key)
cls._processes.pop(key)
@classmethod
def GetReturncode(cls, key):
return cls._processes[key].proc.returncode
@classmethod
def ReadStdout(cls, key):
"""Returns all stdout since the last call to ReadStdout.
This call allows the user to read stdout while the process is running.
However each call will flush the local stdout buffer. In order to make
multiple calls to ReadStdout and to retain the entire output the results
of this call will need to be buffered in the calling code.
"""
proc = cls._processes[key]
with proc.data_lock:
# Perform a "read" on the stdout data
stdout = proc.stdout
proc.stdout = ''
return stdout
@classmethod
def ReadStderr(cls, key):
"""Returns all stderr read since the last call to ReadStderr.
See ReadStdout for additional details.
"""
proc = cls._processes[key]
with proc.data_lock:
# Perform a "read" on the stderr data
stderr = proc.stderr
proc.stderr = ''
return stderr
@classmethod
def Wait(cls, key):
return cls._processes[key].proc.wait()
@classmethod
def Poll(cls, key):
return cls._processes[key].proc.poll()
@classmethod
def GetPid(cls, key):
return cls._processes[key].proc.pid
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