docker-xonsh-wrapper shows the way to wrap an app (e.g. server) in docker container using xonsh shell to:

• catching the signals from docker (SIGTERM, SIGINT, SIGHUP)
• doing work before starting the app
• doing work after stopping the app

To achieve this install xonsh in the container and use run.xsh as an entrypoint.

If you like the idea of xxh click ⭐ on the repo and stay tuned.

Build and run the demo container

git clone https://github.com/anki-code/docker-xonsh-wrapper
cd xonsh-docker-wrapper
docker build . -t local/docker-xonsh-wrapper
docker run --rm -it local/docker-xonsh-wrapper

Example

docker run --rm -it local/docker-xonsh-wrapper
# [Work before running the app]
# The app just sleep 2 minutes zZzZzZz...
#
#                 # Run docker stop, docker restart or press Ctrl+C
#
# CATCH: signum=15, stopping the process...            
#
#                 # After getting closing signal the app could take time 
#                 # to stopping (closing the database, clean the memory) 
#                 # and we're waiting the ending before doing final work.
#
# [Work after running the app or getting stop signals]

Related links

• Real life example - metabase-sql-wrapper
• Trapping signal from “docker stop” in bash