This is a quick script designed to run a command in a new process group, while keeping a connection to the parent, spawned (pun intended) out of necessity due to Upstart's behaviour of killing an entire process group, which plays havoc with Celery's monitoring of its worker processes and prevents clean shutdown of Celery masters.
If you run a command using upstart-shield and then send a TERM signal to the upstart-shield process, it will send a TERM to the process of the command it spawned (but not the process group). This allows things like celery to do their relevant clean exits.
Similarly if the command's main process terminates then upstart-shield will also terminate, allowing upstart to restart it (and therefore the app)
pip install [email protected]:Demoncode/upstart-shield.git#egg=upstart-shield
git clone [email protected]:Demoncode/upstart-shield.gitworkon my-dev-virtualenvcd upstart-shieldpython setup.py develop
upstart-shield cmd arg1 arg2 ...
If you are using upstart, then don't use the expect fork or expect daemon options.