CODEWITHSUNDEEP
dockergithub-actionsghcr
Oliver Angelil
Oliver Angelil

Reputation: 1284

pull docker image from ghcr.io in github actions

I'm using the below workflow code (found in the github documentation) to build and publish a docker image to the Github Container Registry.

name: Create and publish a Docker image

on:
  push:
    branches: ['release']
  pull_request: 
    branches: ['release'] 

env:
  REGISTRY: ghcr.io
  IMAGE_NAME: ${{ github.repository }}

jobs:
  build-and-push-image:
    runs-on: ubuntu-latest
    permissions:
      contents: read
      packages: write

  steps:
    - name: Checkout repository
      uses: actions/checkout@v3

    - name: Log in to the Container registry
      uses: docker/login-action@f054a8b539a109f9f41c372932f1ae047eff08c9
      with:
        registry: ${{ env.REGISTRY }}
        username: ${{ github.actor }}
        password: ${{ secrets.GITHUB_TOKEN }}

    - name: Extract metadata (tags, labels) for Docker
      id: meta
      uses: docker/metadata-action@98669ae865ea3cffbcbaa878cf57c20bbf1c6c38
      with:
        images: ${{ env.REGISTRY }}/${{ env.IMAGE_NAME }}

    - name: Build and push Docker image
      uses: docker/build-push-action@ad44023a93711e3deb337508980b4b5e9bcdc5dc
      with:
        context: .
        push: true
        tags: ${{ steps.meta.outputs.tags }}
        labels: ${{ steps.meta.outputs.labels }}

This works and I now see a public docker image under "Packages" on the github repo. When I click on the image, I am directed to a github page with more information about the image (official docs here): "Install from the command line:" docker pull ghcr.io/OWNER/IMAGE_NAME:pr-75

And its Digest sha: sha256:04ea7757e34c4fae527bbe6fb56eb984f54543f2313775572f0817d696ecf48a

I want to add a new job to the same workflow, that pulls the image to a virtual machine using ssh.

deploy:
  - name: Deploy to Digital Ocean droplet via SSH action
    uses: appleboy/[email protected]
    with:
      host: ${{ secrets.DO_HOST }}
      username: root
      key: ${{ secrets.DO_PRIVATE_SSHKEY }}
      port: 22
      script: |
        docker pull ${{ env.REGISTRY }}/${{ env.IMAGE_NAME }}

This fails with: err: invalid reference format: repository name must be lowercase (lowercasing it is not enough, read on)

Of course I cannot hard-code docker pull ghcr.io/OWNER/IMAGE_NAME:pr-75 or the Digest sha, because each new branch will increment in its PR number, so the pr-75 tag will change.

How can I deploy the image that was just published? Seems I can either use the tag value or the sha and how can I retrieve those values in real time?

Upvotes: 2

Views: 10950

Answers (1)

Oliver Angelil
Oliver Angelil

Reputation: 1284

There are two jobs in the above workflow:

  1. "build-and-push-image"
  2. "deploy"

The first one uses the docker/metadata-action to retrieve the tag name ghcr.io/OWNER/IMAGE_NAME:pr-75 which is used in the next step to name the image when docker/build-push-action is used.

I have simply used the docker/metadata-action again in the second job:

deploy:
  needs: build-and-push-image
  runs-on: ubuntu-latest
  steps:
    - name: Extract metadata (tags, labels) for Docker
      id: meta
      uses: docker/metadata-action@69f6fc9d46f2f8bf0d5491e4aabe0bb8c6a4678a
      with:
        images: ${{ env.REGISTRY }}/${{ env.IMAGE_NAME }}

    - name: Deploy to Digital Ocean droplet via SSH action
      uses: appleboy/[email protected]
      with:
        host: ${{ secrets.DO_HOST }}
        username: root
        key: ${{ secrets.DO_PRIVATE_SSHKEY }}
        port: 22
        script: |
          docker pull ${{ steps.meta.outputs.tags }}

Upvotes: 1

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