Honour DOCKER_CONFIG location for jib credentials

[njlaw]

Description

Presently, jib looks in multiple locations for Docker registry credentials; however, the JibProcessor in Quarkus does not use the same order and only looks for ${user.home}/.docker/config.json. Ideally the Quarkus jib processor would use the same lookup order as the upstream jib tools.

Implementation ideas

Perhaps leveraging the DefaultCredentialRetrievers from the upstream project would make the most sense? I'm happy to attempt a pull request, but I'm not particularly familiar with the Quarkus coding style or project in general.

[quarkus-bot]

/cc @geoand

[geoand]

This is not true, see this.

Are you seeing an issue where this does not work?

[njlaw]

This is not true, see this.

Are you seeing an issue where this does not work?

If I'm reading it correctly, the logic in that function uses the supplied username and password if present; otherwise, it adds the credential helpers and the default Docker config.json file to the credential search path. However, it does not take into account the DOCKER_CONFIG environment variable if it is set.

The upstream DefaultCredentialRetrievers does and adds a fair number of other Docker config locations.

Here's some log output from an instance where the DOCKER_CONFIG environment variable is set, but it still uses the default path:

❯ export DOCKER_CONFIG=$(mktemp -d)
❯ docker login
Login with your Docker ID to push and pull images from Docker Hub. If you don't have a Docker ID, head over to https://hub.docker.com to create one.
Username: njlaw
Password: 
WARNING! Your password will be stored unencrypted in /tmp/tmp.BrRabcWpIm/config.json.
Configure a credential helper to remove this warning. See
https://docs.docker.com/engine/reference/commandline/login/#credentials-store

Login Succeeded
❯ mvn package  -Dquarkus.container-image.builder=jib -Dquarkus.jib.base-jvm-image=njlaw/some-private-image:11 -Dquarkus.container-image=njlaw/my-ptivate:latest -Dquarkus.container-image.build=true
...
[INFO] [io.quarkus.container.image.jib.deployment.JibProcessor] The base image requires auth. Trying again for njlaw/some-private-image:11...
[INFO] [io.quarkus.container.image.jib.deployment.JibProcessor] LogEvent [level=INFO, message=Docker config auths section defines credentials for registry-1.docker.io]
[INFO] [io.quarkus.container.image.jib.deployment.JibProcessor] LogEvent [level=LIFECYCLE, message=Using credentials from Docker config (/home/njlaw/.docker/config.json) for njlaw/some-private-image:11]

[geoand]

Thanks for the update.

Fair enough, we can add support for DOCKER_CONFIG as well.