DEV: Use exec for IPython commands.

[ssanderson]

This makes the SIGTERM sent by docker stop hit the correct process.

[ssanderson]

Looks like this doesn't actually work: it makes docker stop work correctly, but ipython notebook can't spawn kernels if it's been exec'ed. I'm seeing that behavior outside of docker as well, so I'm guessing there's a bug in the interaction between IPython and exec

[rgbkrk]

😒

[ssanderson]

@rgbkrk FYI, the note here regarding seeing weirdness with exec outside of docker turned out not to be true.

I'm working around this right now using more or less the solution described as Option 3 in https://github.com/ipython/docker-notebook/issues/38.

# Forward SIGINT AND SIGTERM
_forward_sigint(){
    echo "forwarding int"
    kill -SIGINT $NOTEBOOK_PID
}
_forward_sigterm(){
    echo "forwarding term"
    kill -SIGTERM $NOTEBOOK_PID
}
trap _forward_sigterm SIGTERM
trap _forward_sigint SIGINT

# Run notebook in the background so we can get its pid.
ipython notebook --no-browser --port 8888&

NOTEBOOK_PID=$!
wait $NOTEBOOK_PID

[Carreau]

Should we close this one?

[rgbkrk]

I'll leave that up to @ssanderson.

@parente has been using supervisord inside docker-stacks.

[parente]

@krallin recommended tini as a replacement for supervisord (jupyter/docker-stacks#24 (comment)) I plan to look into it soon for the docker-stacks.

[rgbkrk]

Closing since this has been in a WIP state for a while, re-open if we continue on with it.