Publish AWS ECR multiplatform docker images in Github Actions

readme.md

Publish AWS ECR multiplatform docker images in Github Actions

In Github actions

1. Get an AWS login somehow. See https://github.com/aws-actions/configure-aws-credentials. Steps:

    - name: Configure AWS credentials
      uses: aws-actions/configure-aws-credentials@v4
      with:
        audience: sts.amazonaws.com
        aws-region: YOUR REGION HERE
        role-to-assume: ARN GOES HERE

2. Install the AWS ECR credential helper in CI

   sudo apt update && sudo apt install amazon-ecr-credential-helper
   mkdir -p ~/.docker
   touch ~/.docker/config.json
   cat ~/.docker/config.json
   echo '{
   "credsStore": "ecr-login"
   }' > ~/.docker/config.json

3. Build 1+ docker images for different platforms. Ideally you use Docker's buildx plugin, maybe needing QEMU installed, to just build two images + the manifest to reference them. See Docker's docs. Just use Github's action for this and save yourself a headache. Make sure to add the --platform args via with: platforms: linux/amd64,linux/arm64
4. If you can't do that, because e.g. you need to build with two different contexts or something, you're going to need to
   1. build two images using different --platform args

      docker buildx build . \
        --platform linux/$ARCHITECTURE \ # "arm64" (mac M-class chips or Graviton instances) or "amd64" (most computers)
        -t ${DOCKER_IMAGE_NAME} \        # Your docker image[:tag]
        --progress plain \               # Easier for CI
        --output type=docker \           # I don't know why this is here but I ended up needing it
        --target $DOCKER_BUILD_TARGET    # for multistage builds

   2. Build a manifest from scratch, referencing both images, and then push that to your docker repo

      ECR_IMAGE=public.ecr.aws/SOMEURL
      LOCAL_TAG=my-local-docker-image
      ARM_FOR_MAC=arm64
      INTEL_FOR_EVERYTHING_ELSE=amd64
      
      docker images
      
      docker tag ${LOCAL_TAG}-${INTEL_FOR_EVERYTHING_ELSE} ${ECR_IMAGE}:latest-${INTEL_FOR_EVERYTHING_ELSE}
      docker tag ${LOCAL_TAG}-${ARM_FOR_MAC} ${ECR_IMAGE}:latest-${ARM_FOR_MAC}
      
      docker push ${ECR_IMAGE}:latest-${INTEL_FOR_EVERYTHING_ELSE}
      docker push ${ECR_IMAGE}:latest-${ARM_FOR_MAC}
      
      docker manifest rm ${ECR_IMAGE} || echo "Already no local manifest"
      
      docker manifest create --amend ${ECR_IMAGE} \
        ${ECR_IMAGE}:latest-${INTEL_FOR_EVERYTHING_ELSE} \
        ${ECR_IMAGE}:latest-${ARM_FOR_MAC}
      
      docker manifest inspect ${ECR_IMAGE
      docker manifest push ${ECR_IMAGE}