How to completely exit a running asyncio script in python3
I'm working on a server bot in python3 (using asyncio), and I would like to incorporate an update function for collaborators to instantly test their contributions. It is hosted on a VPS that I access via ssh. I run the process in tmux and it is often difficult for other contributors to relaunch the script once they have made a commit, etc. I'm very new to python, and I just use what I can find. So far I have used subprocess.Popen to run git pull, but I have no way for it to automatically restart the script.
Is there any way to terminate a running asyncio loop (ideally without errors) and restart it again?
You can not start a event loop stopped by event_loop.stop() And in order to incorporate the changes you have to restart the script anyways (some methods might not exist on the objects you have, etc.)
I would recommend something like:
asyncio.ensure_future(git_tracker) async def git_tracker(): # check for changes in version control, maybe wait for a sync point and then: sys.exit(0)
This raises SystemExit, but despite that exits the program cleanly.
And around the
python $file.py a
while true; do git pull && python $file.py ; done
This is (as far as I know) the simplest approach to solve your problem.
python 3.x, You can not start a event loop stopped by event_loop.stop() And in order to incorporate the changes you have to restart the script anyways (some methods might� Practical Tutorial on Asyncio in Python 3.7 7 minute read Introduction. Asyncio has become quite popular in the python ecosystem. From using it in small functions to large microservices, it’s benefits are widely recognized. In this blog, I’ll share my understanding of asyncio and how you can see it.
For your use case, to stay on the safe side, you would probably need to kill the process and relaunch it.
See also: Restart process on file change in Linux
Subprocesses — Python 3.8.5 documentation, Here's an example of how asyncio can run a shell command and obtain its and asyncio provides many tools to work with such functions, it is easy to execute This condition occurs when the process exits before all data are written into stdin. You can retrieve unfinished tasks and run the loop again until they finished, then close the loop or exit your program. pending = asyncio.all_tasks() loop.run_until_complete(asyncio.gather(*pending)) pending is a list of pending tasks. asyncio.gather() allows to wait on several tasks at once.
As a necromancer, I thought I give an up-to-date solution which we use in our UNIX system.
Using the os.execl function you can tell python to replace the current process with a new one:
These functions all execute a new program, replacing the current process; they do not return. On Unix, the new executable is loaded into the current process, and will have the same process id as the caller. Errors will be reported as OSError exceptions.
In our case, we have a bash script which executes the
killall python3.7, sending the SIGTERM signal to our python apps which in turn listen to it via the signal module and gracefully shutdown:
loop = asyncio.get_event_loop() loop.call_soon_threadsafe(loop.stop) sys.exit(0)
The script than starts the apps in background and finishes.
killall python3.7will send
SIGTERMsignal to every python3.7 process!
When we need to restart we jus rune the following command:
The first parameter is the path to the file and the second is the name of the process.
Graceful Shutdowns with asyncio – roguelynn, Foreword: This part 2 of a 7-part series titled “asyncio: We Did It #!/usr/bin/env python3.7 """ Notice! This is because without that, we end up running into an apparently If it's a manually-ran script, then SIGINT is fine. You can also use simply exit (). Keep in mind that sys.exit (), exit (), quit (), and os._exit (0) kill the Python interpreter. Therefore, if it appears in a script called from another script by execfile (), it stops execution of both scripts. See " Stop execution of a script called with execfile " to avoid this.
Async IO in Python: A Complete Walkthrough – Real Python, asyncio : the Python package that provides a foundation and API for running and managing #!/usr/bin/env python3 # countasync.py import asyncio async def count(): a coroutine that has temporarily ceded control but not totally exited or finished. This script is longer than our initial toy programs, so let's break it down . asyncio.run(), introduced in Python 3.7, is responsible for getting the event loop, running tasks until they are marked as complete, and then closing the event loop. There’s a more long-winded way of managing the asyncio event loop, with get_event_loop(). The typical pattern looks like this:
asyncio, _run_once() File "C:\Python\Python3\lib\asyncio\base_events.py", line 1722, Why do you want to exit a long running server process like this? aspects of Python programming with an emphasis on script writing, data manipulation, and� ThreadPoolExecutor (max_workers = 3,) event_loop = asyncio. get_event_loop try: event_loop. run_until_complete (run_blocking_tasks (executor)) finally: event_loop. close () asyncio_executor_thread.py uses logging to conveniently indicate which thread and function are producing each log message.