restart workers online (graceful restart) to hot reload, in production environment.

Is there an existing issue for this?

• I have searched the existing issues

Is your feature request related to a problem? Please describe.

Condition: keep service available any time.

---- client code----

async def run():                                                                                        
    while 1:
        await post('http://127.0.0.1:8000/') 

when called app.m.restart(“ALL_PROCESSES”) in a worker, sanic crashed.

---- server code ----

@app.post("/")
async def handler(request):
    app.m.restart('__ALL_PROCESSES__')
    return response.text('ok')


if __name__ == "__main__":
    app.run(debug=True, workers=2)

Describe the solution you’d like

graceful restarting and reduce the effect when restarting. my messy describe:

1. graceful restart workers; restart all workers will not crash, if only 1 worker, block a little while (if worker not started yet) is ok.
2. a way to graceful restart worker one by one, code eg: woker_names = tuple(app.m.workers.keys()) for woker_name in worker_names: ret_val = app.m.restart(worker_name) # here, the worker has been graceful restarted, ret_val is meaningful
3. may combine the above 2, when restarting all workers, 50% workers restarting, 50% old workers keep serving

Additional context

simplify the api,

app.m.restart('__ALL_PROCESSES__')   => app.m.restart_all()

thanks.

[yangbo1024]

I think it’s okay to do a good job of HTTP link processing with short responses, and the same is true for my personal needs. Restarting the main process, modifying the IP address and port is not considered. For some long-term services, such as websockets, streams, etc., they can be handled by sanic user, including but not limited to deliberately increasing the waiting time for graceful closing. Otherwise, the sanic becomes too complex and even brings more bugs, which is not friendly to the majority of users.

[yangbo1024]

amazing! thats it