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gns3-server/gns3server/utils/asyncio/__init__.py

161 lines
4.8 KiB
Python

# -*- coding: utf-8 -*-
#
# Copyright (C) 2015 GNS3 Technologies Inc.
#
# This program is free software: you can redistribute it and/or modify
# it under the terms of the GNU General Public License as published by
# the Free Software Foundation, either version 3 of the License, or
# (at your option) any later version.
#
# This program is distributed in the hope that it will be useful,
# but WITHOUT ANY WARRANTY; without even the implied warranty of
# MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the
# GNU General Public License for more details.
#
# You should have received a copy of the GNU General Public License
# along with this program. If not, see <http://www.gnu.org/licenses/>.
import functools
import asyncio
import sys
import os
@asyncio.coroutine
def wait_run_in_executor(func, *args, **kwargs):
"""
Run blocking code in a different thread and wait
for the result.
:param func: Run this function in a different thread
:param args: Parameters of the function
:param kwargs: Keyword parameters of the function
:returns: Return the result of the function
"""
loop = asyncio.get_event_loop()
future = loop.run_in_executor(None, functools.partial(func, *args, **kwargs))
yield from asyncio.wait([future])
return future.result()
@asyncio.coroutine
def subprocess_check_output(*args, cwd=None, env=None, stderr=False):
"""
Run a command and capture output
:param *args: List of command arguments
:param cwd: Current working directory
:param env: Command environment
:param stderr: Read on stderr
:returns: Command output
"""
if stderr:
proc = yield from asyncio.create_subprocess_exec(*args, stderr=asyncio.subprocess.PIPE, cwd=cwd, env=env)
output = yield from proc.stderr.read()
else:
proc = yield from asyncio.create_subprocess_exec(*args, stdout=asyncio.subprocess.PIPE, cwd=cwd, env=env)
output = yield from proc.stdout.read()
if output is None:
return ""
# If we received garbage we ignore invalid characters
# it should happens only when user try to use another binary
# and the code of VPCS, dynamips... Will detect it's not the correct binary
return output.decode("utf-8", errors="ignore")
@asyncio.coroutine
def wait_for_process_termination(process, timeout=10):
"""
Wait for a process terminate, and raise asyncio.TimeoutError in case of
timeout.
In theory this can be implemented by just:
yield from asyncio.wait_for(self._iou_process.wait(), timeout=100)
But it's broken before Python 3.4:
http://bugs.python.org/issue23140
:param process: An asyncio subprocess
:param timeout: Timeout in seconds
"""
if sys.version_info >= (3, 5):
try:
yield from asyncio.wait_for(process.wait(), timeout=timeout)
except ProcessLookupError:
return
else:
while timeout > 0:
if process.returncode is not None:
return
yield from asyncio.sleep(0.1)
timeout -= 0.1
raise asyncio.TimeoutError()
@asyncio.coroutine
def _check_process(process, termination_callback):
if not hasattr(sys, "_called_from_test") or not sys._called_from_test:
returncode = yield from process.wait()
if asyncio.iscoroutinefunction(termination_callback):
yield from termination_callback(returncode)
else:
termination_callback(returncode)
def monitor_process(process, termination_callback):
"""Call termination_callback when a process dies"""
asyncio.async(_check_process(process, termination_callback))
@asyncio.coroutine
def wait_for_file_creation(path, timeout=10):
while timeout > 0:
if os.path.exists(path):
return
yield from asyncio.sleep(0.5)
timeout -= 0.5
raise asyncio.TimeoutError()
@asyncio.coroutine
def wait_for_named_pipe_creation(pipe_path, timeout=60):
import win32pipe
import pywintypes
while timeout > 0:
try:
win32pipe.WaitNamedPipe(pipe_path, 1)
except pywintypes.error:
yield from asyncio.sleep(0.5)
timeout -= 0.5
else:
return
raise asyncio.TimeoutError()
def locked_coroutine(f):
"""
Method decorator that replace asyncio.coroutine that warranty
that this specific method of this class instance will not we
executed twice at the same time
"""
@asyncio.coroutine
def new_function(*args, **kwargs):
# In the instance of the class we will store
# a lock has an attribute.
lock_var_name = "__" + f.__name__ + "_lock"
if not hasattr(args[0], lock_var_name):
setattr(args[0], lock_var_name, asyncio.Lock())
with (yield from getattr(args[0], lock_var_name)):
return (yield from f(*args, **kwargs))
return new_function