Docker Compose Tailing of Log Files
Docker Compose Logs
docker compose logs aggregates stdout of containers started with no out-of-the-box
capability for aggregating additional logs generated on container filesystems.
Implementing
sidecar
allows tailing logs generated on container volumes.
docker-compose.yaml
services:
counter:
image: busybox
command: |
/bin/sh -c 'i=0; while true; do echo "$$(date) WARN $$i" >> /var/log/1.log; echo "$$(date) INFO $$i" >> /var/log/2.log; i=$$((i+1)); sleep 5; done'
volumes:
- log-volume:/var/log
counter-log:
image: busybox
command: |
/bin/sh -c 'tail -n+1 -F /var/log/*.log'
volumes:
- log-volume:/var/log
volumes:
log-volume:
name: counter-log-volume
Running
➜ docker compose up
[+] Running 4/4
⠿ Network 202204_docker_default Created 0.1s
⠿ Volume "counter-log-volume" Created 0.0s
⠿ Container 202204_docker-counter-log-1 Created 0.1s
⠿ Container 202204_docker-counter-1 Created 0.1s
Attaching to 202204_docker-counter-1, 202204_docker-counter-log-1
202204_docker-counter-log-1 | ==> /var/log/1.log <==
202204_docker-counter-log-1 | Sat Apr 23 01:37:03 UTC 2022 WARN 0
202204_docker-counter-log-1 |
202204_docker-counter-log-1 | ==> /var/log/2.log <==
202204_docker-counter-log-1 | Sat Apr 23 01:37:03 UTC 2022 INFO 0
202204_docker-counter-log-1 |
202204_docker-counter-log-1 | ==> /var/log/1.log <==
202204_docker-counter-log-1 | Sat Apr 23 01:37:08 UTC 2022 WARN 1
202204_docker-counter-log-1 |
202204_docker-counter-log-1 | ==> /var/log/2.log <==
202204_docker-counter-log-1 | Sat Apr 23 01:37:08 UTC 2022 INFO 1
^C
Cleanup
docker compose down
docker volume rm counter-log-volume