Docker

docker-compose can specify one or multiple yml files, also about config option.

docker-compose -f docker-compose-dev.yml up

specify yml file.

docker-compose -f docker-compose-base.yml -f docker-compose-dev.yml up

multiple -f can merge multiple yml file. Different parts will be merged, and for overlapped parts, later file will override former files.

docker-compose -f docker-compose-base.yml -f docker-compose-dev.yml config

docker-compose <...> config can display final config structure.

Why I cannot catch docker-compose down signal

I write a python code, to catch terminate signal,

import signal

signal.signal(signal.SIGTERM, signal_handler)
signal.signal(signal.SIGWINCH, signal_handler)
signal.signal(signal.SIGINT, signal_handler)

However I found using docker-compose down, the program cannot catch the signal. very confusing. then found this article.

Why Your Dockerized Application Isn’t Receiving SignalsHynek Schlawack

copy:

https://www.evernote.com/l/AB1zfELghxNLSZXbqeBgkx_mbQAQFsGktd0/

Summary

• Use the exec/JSON array form of ENTRYPOINT.

• Use exec in shell entrypoints.

• Don’t pipe your application’s output.

• Avoid being PID 1.

• Listen for SIGTERM or set STOPSIGNAL in your Dockerfile.

Most ignore part is exec one:

note

So instead of

/app/bin/your-app 

do

exec /app/bin/your-app