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gns3-server/gns3server/utils/asyncio/__init__.py
2022-01-19 22:28:36 +10:30

149 lines
4.6 KiB
Python

#
# 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
import threading
async 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))
await asyncio.wait([future])
return future.result()
async def cancellable_wait_run_in_executor(func, *args, **kwargs):
"""
Run blocking code in a different thread and wait
for the result. Support cancellation.
: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
"""
stopped_event = threading.Event()
kwargs["stopped_event"] = stopped_event
try:
await wait_run_in_executor(func, *args, **kwargs)
except asyncio.CancelledError:
stopped_event.set()
async 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 = await asyncio.create_subprocess_exec(*args, stderr=asyncio.subprocess.PIPE, cwd=cwd, env=env)
output = await proc.stderr.read()
else:
proc = await asyncio.create_subprocess_exec(*args, stdout=asyncio.subprocess.PIPE, cwd=cwd, env=env)
output = await 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")
async 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:
await 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:
await asyncio.wait_for(process.wait(), timeout=timeout)
except ProcessLookupError:
return
else:
while timeout > 0:
if process.returncode is not None:
return
await asyncio.sleep(0.1)
timeout -= 0.1
raise asyncio.TimeoutError()
async def _check_process(process, termination_callback):
if not hasattr(sys, "_called_from_test") or not sys._called_from_test:
returncode = await process.wait()
if asyncio.iscoroutinefunction(termination_callback):
await termination_callback(returncode)
else:
termination_callback(returncode)
def monitor_process(process, termination_callback):
"""Call termination_callback when a process dies"""
asyncio.ensure_future(_check_process(process, termination_callback))
async def wait_for_file_creation(path, timeout=60):
while timeout > 0:
if os.path.exists(path):
return
await asyncio.sleep(0.5)
timeout -= 0.5
raise asyncio.TimeoutError()
def locking(f):
@functools.wraps(f)
async def wrapper(oself, *args, **kwargs):
lock_name = "__" + f.__name__ + "_lock"
if not hasattr(oself, lock_name):
setattr(oself, lock_name, asyncio.Lock())
async with getattr(oself, lock_name):
return await f(oself, *args, **kwargs)
return wrapper