Support logging to multiple registries with a single execution of the Action

[umarcor]

Currently, I need to login to three registries, which makes it very verbose to use this Action:

    - name: Login to ghcr.io
      uses: docker/login-action@v1
      with:
        registry: ghcr.io
        username: gha
        password: ${{ github.token }}
        
    - name: Login to docker.io
      uses: docker/login-action@v1
      with:
        username: ${{ secrets.DOCKER_USERNAME }}
        password: ${{ secrets.DOCKER_PASSWORD }}
        
    - name: Login to GCR
       uses: docker/login-action@v1
       with:
         registry: gcr.io
         username: _json_key
         password: ${{ secrets.GCR_JSON_KEY }}

It would be nice if providing a list of targets was supported. For instance:

    - name: Login to container registries
      uses: docker/login-action@v2
      with:
        targets:
          - 'ghcr.io|gha|${{ github.token }}'
          - 'docker.io|${{ secrets.DOCKER_USERNAME }}|${{ secrets.DOCKER_PASSWORD }}'
          - 'gcr.io|_json_key|${{ secrets.GCR_JSON_KEY }}'

[crazy-max]

Don't think that's smth we are going to handle here but nested actions through a composite action could be a good fit for that (actions/runner#646).

[umarcor]

Don't think that's smth we are going to handle

That's unfortunate...

nested actions through a composite action could be a good fit for that

Composite actions cannot use other actions. It does not seem that will change in the near future...

Moreover, due to #25 and #30 (see https://github.com/dbhi/vunit/runs/2802152583?check_suite_focus=true#step:3:10), it does not feel sensible to try working around the limitations. FTR, I'll use the following syntax for now:

- name: Login to container registries
  run: |
    echo '${{ github.token }}' | docker login ghcr.io -u gha --password-stdin
    echo '${{ secrets.DOCKER_PASSWORD }}' | docker login docker.io -u '${{ secrets.DOCKER_USERNAME }}' --password-stdin
    echo '${{ secrets.GCR_JSON_KEY }}' | docker login gcr.io -u _json_key --password-stdin

[tpolekhin]

@crazy-max I understand why you don't want to support multiple logins in one action for different registry types, but what about the same one?
Right now we're using this action to login to IBM Cloud Container Registry in different regions:

      - name: Login to IBM Cloud Container Registry US
        uses: docker/login-action@v1
        with:
          registry: us.icr.io
          username: ${{ env.ICR_USERNAME }}
          password: ${{ env.ICR_PASSWORD }}

      - name: Login to IBM Cloud Container Registry UK
        uses: docker/login-action@v1
        with:
          registry: uk.icr.io
          username: ${{ env.ICR_USERNAME }}
          password: ${{ env.ICR_PASSWORD }}

Credentials are the same for all regions, it's just the address of the registry that differs.

Could we possibly support something like this?

      - name: Login to IBM Cloud Container Registry ALL
        uses: docker/login-action@v1
        with:
          registry: |
            us.icr.io
            uk.icr.io
            de.icr.io
            au.icr.io
            jp.icr.io
          username: ${{ env.ICR_USERNAME }}
          password: ${{ env.ICR_PASSWORD }}

[crazy-max]

@tpolekhin Thanks for your feedback, that sounds like legitimate to me so yes I think we could improve the current behavior. About design I will think about it. I also saw the composite actions ADR recently that could be beneficial for this use case.

[umarcor]

I'm closing this issue since the proposed feature is not to be implemented here.

FTR, I'm using a single plain JavaScript file as an alternative:

    - name: Login to container registries
      if: github.event_name != 'pull_request' && github.repository == 'hdl/containers'
      uses: ./utils/registry-login
      with:
        cmd: |
          echo '${{ secrets.GCR_JSON_KEY }}' | docker login gcr.io -u _json_key --password-stdin
          echo '${{ github.token }}' | docker login ghcr.io -u gha --password-stdin
          echo '${{ secrets.DOCKER_PASS }}' | docker login docker.io -u '${{ secrets.DOCKER_USER }}' --password-stdin

const { exec } = require('child_process');

function run(cmd) {
  exec(cmd, (error, stdout, stderr) => {
    if ( stdout.length != 0 ) { console.log(`${stdout}`); }
    if ( stderr.length != 0 ) { console.error(`${stderr}`); }
    if (error) {
      console.error(`exec error: ${error}`);
    }
    return error;
  });
}

// Are we in the 'post' step?
const registries = process.env.STATE_REGISTRIES;
if ( registries != undefined ) {
  for ( const item of registries.split(',') ) { run(`docker logout ${item.trim()}`); };
  return;
}

// Otherwise, this is the main step
run(process.env.INPUT_CMD);
console.log(`::save-state name=REGISTRIES::gcr.io,ghcr.io,docker.io`);

Ref: https://github.com/hdl/containers/tree/main/utils/registry-login