Moby: Add ability to have a shutdown hook

[noahwhite]

It would be useful to have the ability to set a stop/shutdown hook. Much like ENTRYPOINT but for when docker stop is run. Docker stop I believe sends a SIGKILL 15 then a KILL 9 (die damn you) which pulls the rug out from under the processes. If you could set up an EXITPOINT process then it would be possible to point it at a shell script or such which could gracefully shut things down prior to container stoppage.

[vieux]

There is work done around hooks, they will look like git hooks (drop a binary in the right directory and it'll be executed) We don't have any ETA for now, but it'll be merged.

[unclejack]

Hooks are going to be added for other features as well, not only shutdown.

I'll close this issue now because a larger planned feature will add this and this issue isn't immediately actionable. Please feel free to comment.

[jcoffland]

Shouldn't have closed this. It's not been addressed.