Gitlab DOCKER_AUTH_CONFIG not working

Question

The following are in my .gitlab-ci.yml

stages:
  - build

variables:
  DOCKER_HOST: tcp://docker:2375/
  DOCKER_DRIVER: overlay2

services:
  - docker:dind

build-image:
  image: docker:stable
  stage: build
  script:
    - docker build --no-cache -t repo/myimage:$CI_JOB_ID .
    - docker push repo/myimage:$CI_JOB_ID

I've setup the DOCKER_AUTH_CONFIG in Gitlab like following (to contain all possibilities of matching)

{
    "auths": {
        "https://index.docker.io": {
            "auth": "...."
        },
        "https://index.docker.io/v1/": {
            "auth": "..."
        },
        "https://index.docker.io/v2/": {
            "auth": "..."
        },
        "index.docker.io/v1/": {
            "auth": "..."
        },
        "index.docker.io/v2/": {
            "auth": "..."
        },
        "docker.io/repo/myimage": {
            "auth": "..."
        }

    }
}

However, whenever trying to push the image, the following error occurred

$ docker push repo/myimage:$CI_JOB_ID
The push refers to repository [docker.io/repo/myimage]
ce6466f43b11: Preparing
719d45669b35: Preparing
3b10514a95be: Preparing
63dcf81c7ca7: Waiting
3b10514a95be: Waiting
denied: requested access to the resource is denied
ERROR: Job failed: exit code 1

It worked when I use docker login with username/password. Anyone please show me what I did wrong to get it to work with DOCKER_AUTH_CONFIG?

Thanks heaps

Regards Tin

Answer 1

To use the content of DOCKER_AUTH_CONFIG as docker login, just store it in $HOME/.docker/config.json, e.g. as follows:

before_script:
  - mkdir -p $HOME/.docker
  - echo $DOCKER_AUTH_CONFIG > $HOME/.docker/config.json

Ref: https://docs.gitlab.com/ee/ci/docker/using_docker_build.html#option-3-use-docker_auth_config

This allows to use a single config to load images for build containers and to access the registry inside the build from the same configuration source.

note: this replaces an execution of docker login

see also: https://docs.docker.com/engine/reference/commandline/login/#privileged-user-requirement