Container logs with docker compose like legacy docker-compose

Docker Engine Compose
1

When I run docker compose, it prints logs for creating the container but then just waits for the container to exit.

[+] Building 0.6s (26/26) FINISHED
 => [internal] load build definition from Dockerfile                                                                                                                                                                                                                                                                                                         

[...building from cache log entries...]

Use 'docker scan' to run Snyk tests against images to find vulnerabilities and learn how to fix them
[+] Running 1/0
 ⠿ Container docs-builder  Recreated                                                                                                                                                                                                                                                                                                                         0.1s
Attaching to docs-builder
docs-builder exited with code 2

When running the same command but with the legacy docker-compose instead of docker compose, it also prints the logs from the container

Building build-docs
[+] Building 0.3s (26/26) FINISHED
 => [internal] load build definition from Dockerfile      

[...building from cache log entries...]                                                                                                                                                                                                                                                                                                    

Use 'docker scan' to run Snyk tests against images to find vulnerabilities and learn how to fix them
Recreating docs-builder ... done
Attaching to docs-builder
docs-builder  | Running Sphinx v3.4.3

[...more useful logs from container...]   

docs-builder exited with code 2

Is there any way to get those container logs to show up while using the V2 compose command?

thanks,

2

Normally you should see the logs regardless of the compose version. But… here is my guess. Since I see you run Sphinx which is a Python app for generating documentations, and Docker Compose v1 was written in Python as well, that could be more compatible. In Python, when you run it in a container, you often need to set the

PYTHONUNBUFFERED=1

environment variable in the container to get the logs immediately. So I guess the logs were lost in the buffer but this is indeed just a guess. I had no problem with Compose v2 and logs.

3

No luck with PYTHONUNBUFFERED. My understanding is that if I needed to use PYTHONUNBUFFERED, the logs would still print but only show up when the container exits – but it’s been a while since I’ve had to mess with that.

Interestingly, you’re at least right that it’s not universal – other containers are printing as desired. Will try to determine what’s different.

Thanks