Build and private ECR push action

Build and push a Docker image to a private ECR repository in one action. This action can only be used on private Github repositories. For public repositories, please use this action.

By default it will push the image with three different tags:

• Commit sha, prepended with dev_ e.g. dev_e1b18d15d2b5558d275920ab5b5650a5c36bb1ee
• Branch or Tag on push events or PR Source Branch for pull request events, e.g. main, v1.0.0, feature

When marked as a production image using prod_image: true

• Commit sha, e.g. e1b18d15d2b5558d275920ab5b5650a5c36bb1ee
• Branch or Tag on push events or PR Source Branch for pull request events, e.g. main, v1.0.0, feature
• latest

These can be overridden using the tags_override input.

Please note that the ECR repository must be created beforehand. Repository creation is not currently within the scope of this Action.

Cache

This action will automatically cache Docker image layers to the Github cache, however this feature is experimental.

Authentication

In order to give a repository the AWS permissions required to run this action, the Github repository name and the ECR repository ARN must be added to the PrivateECRPush configuration in the AWS OIDC CDK repository and then deployed. Please send a message to #devops-support in Slack for help with this.

Inputs

Input	Description	Required	Default
role_arn	A role to assume with permission to push to the Private ECR repository	No	'arn:aws:iam::979633842206:role/PrivateECRPush'
dockerfile_context	The path to the Dockerfile context. Will default to the root of the project	No	.
repository_name	The name of the image repository. Is used to name the docker image. Must may contain lowercase and uppercase letters, digits, underscores, periods and dashes only.	Yes
auth_token	A token with permission to clone the repository. Will usually be GITHUB_TOKEN	Yes
multiarch_build	Allow for multi-arch builds. When 'disabled' only builds linux/amd64 images, when 'enabled' also builds linux/arm64 images	No	'enabled'
push_after_build	Push the image after building it. Useful if you need to run tests on the image before you push it	No	true
dockerfile	The name of the dockerfile to be built.	No	Dockerfile
build-args	List of build-time variables.	No
prod_image	Mark the image as a production image. Adds latest tag. When false, adds dev_ to hash tag.	No	false
tags_override	Override the default tags. This will replace ALL of the default tags. Must be a comma separated list with no spaces	No	See default tags above

The user associated with the aws_access_key must have permission to push, update and read the private repository in question.

Due to the fact that the action will be running in an amd64 environment (Also known as x86_64), building the image with multi-arch enabled will cause the build times to increase significantly, so use only when required.

Outputs

Name	Description
image_id	The ID of the built image
image_digest	The digest of the built image
image_tags	A CSV list of the image tags, in the order commit sha,branch/tag,latest

Example usage

Located in .github/workflows/build-and-push.yml:

name: Build and private ECR push action
on:
  push:
    branches:
      - main
      - "[0-9]*"
      - "v[0-9]*"
    tags:
      - v*

jobs:
  build:
    name: Publish image
    runs-on: ubuntu-22.04
    permissions:
      id-token: write
      contents: read
    steps:
      - name: Build and push to ECR
        uses: citizensadvice/build-and-private-ecr-push-action@v1
        with:
            dockerfile_context: '.'
            repository_name: <REPOSITORY NAME HERE>
            auth_token: ${{ secrets.GITHUB_TOKEN }}
            prod_image: true

The on conditions and branch matching can be changes to whatever suites your team best. If you require assistance implementing a custom solution, please send a message to #devops-support in Slack.