All combined docker logs with container name

Question

So I am trying to get the combined output of all the container logs with its container name in a log file docker logs --tail -3 <id> with **container name** >> logst.log file.

Answer 1

docker logs takes a single command so you would have to run them for each container. I guess I could do something along:

docker ps --format='{{.Names}}' | xargs -P0 -d '\n' -n1 sh -c 'docker logs "$1" | sed "s/^/$1: /"' _

• docker ps --format='{{.Names}}' - print container names
• xargs - for input
  • -d '\n' - for each line
  • -P0 - execute in parallel with any count of parallel jobs
    • remove this option if you don't intent to do docker logs --follow
    • it may cause problems, consider adding stdbuf -oL and sed -u to unbuffer the streams
  • -n1 - pass one argument to the underyling process
  • sh -c 'script' _ - execute script for each line with line passed as first positional argument
    • docker logs "$1" - get the logs
    • sed 's/^/$1: /' - prepend the name of the docker name to each log line

But a way better and industrial grade solution would be to forward docker logs to journalctl or other logging solution and use that utility to aggregate and filter logs.