flask\werkzeug: intercept a worker termination

Question

Is there any way to execute some code just before a worker is turned off? I'm not too confident on execution model of flask\werkzeug, the situation is this:

During the creation of flask application i start a deamon thread to do some external stuff (waiting on a queue essentially); i've setup this thread as demon because i don't want it to prevent the shut down of the worker running the flask application when it's needed. there is my problem: i need to execute some clean up code just before the thread it's been killed by the worker, and my solution is to do those operations on a termination event (if any) of the worker

Answer 1

With python you can use the uwsgi.atexit hook. The function callback will be executed before exit.

import uwsgi, os
from flask import Flask
app = Flask('demo')

@app.route('/')
def index():
    return "Hello World"

def callback():
    print "Worker %i exinting" % os.getpid()
uwsgi.atexit = callback