Docker Build & Push Action

Builds a Docker image and pushes it to the private registry of your choosing.

Supported Docker registries

• Docker Hub
• Google Container Registry (GCR)
• AWS Elastic Container Registry (ECR)
• GitHub Docker Registry

Basic usage

• Ensure you run the checkout action before using this action
• Add the following to a workflow .yml file in the /.github directory of your repo

steps:
  - uses: actions/checkout@v1.0
    name: Check out code

  - uses: mr-smithers-excellent/docker-build-push@v3
    name: Build & push Docker image
    with:
      image: repo/image
      tags: v1, latest
      registry: registry-url.io
      dockerfile: Dockerfile.ci
      username: ${{ secrets.DOCKER_USERNAME }}
      password: ${{ secrets.DOCKER_PASSWORD }}

Inputs

Name	Description	Required
image	Docker image name	Yes
tags	Comma separated docker image tags (see Tagging the image with GitOps)	No
registry	Docker registry host	Yes
dockerfile	Location of Dockerfile (defaults to Dockerfile)	No
directory	Directory to pass to docker build command, if not project root	No
buildArgs	Docker build arguments in format KEY=VALUE,KEY=VALUE	No
username	Docker registry username	No
password	Docker registry password or token	No
githubOrg	GitHub organization to push image to (if not current)	No

Outputs

Name	Description	Format
imageFullName	Full name of the Docker image with registry prefix	registry/owner/image
imageName	Name of the Docker image with owner prefix	owner/image
tags	Tags for the Docker image	v1,latest

Examples

Docker Hub

• Save your Docker Hub username (DOCKER_USERNAME) and password (DOCKER_PASSWORD) as secrets in your GitHub repo
• Modify sample below and include in your workflow .github/workflows/*.yml file

uses: mr-smithers-excellent/docker-build-push@v3
with:
  image: docker-hub-repo/image-name
  registry: docker.io
  username: ${{ secrets.DOCKER_USERNAME }}
  password: ${{ secrets.DOCKER_PASSWORD }}

Google Container Registry (GCR)

• Create a service account with the ability to push to GCR (see configuring access control)
• Create and download JSON key for new service account
• Save content of .json file as a secret called DOCKER_PASSWORD in your GitHub repo
• Modify sample below and include in your workflow .github/workflows/*.yml file
• Ensure you set the username to _json_key

uses: mr-smithers-excellent/docker-build-push@v3
with:
  image: gcp-project/image-name
  registry: gcr.io
  username: _json_key 
  password: ${{ secrets.DOCKER_PASSWORD }} 

AWS Elastic Container Registry (ECR)

• Create an IAM user with the ability to push to ECR (see example policies)
• Create and download access keys
• Save AWS_ACCESS_KEY_ID and AWS_SECRET_ACCESS_KEY as secrets in your GitHub repo
• Ensure the repo you are trying to push to already exists, if not create with aws ecr create-repository before pushing
• Modify sample below and include in your workflow .github/workflows/*.yml file

uses: mr-smithers-excellent/docker-build-push@v3
with:
  image: image-name
  registry: [aws-account-number].dkr.ecr.[region].amazonaws.com
env:
  AWS_ACCESS_KEY_ID: ${{ secrets.AWS_ACCESS_KEY_ID }}
  AWS_SECRET_ACCESS_KEY: ${{ secrets.AWS_SECRET_ACCESS_KEY }}

GitHub Docker Registry

• It is assumed you'll be pushing the image to a repo inside your GitHub organization, unless you set githubOrg
• Provide the image name in github-repo-name/image-name format
• Provide either the ${{ github.actor }} or an alternate username for Docker login (with associated token below)
• Pass the default GitHub Actions token or custom secret with proper push permissions

uses: mr-smithers-excellent/docker-build-push@v3
with:
  image: github-repo/image-name
  registry: docker.pkg.github.com
  githubOrg: override-org # optional
  username: ${{ github.actor }}
  password: ${{ secrets.GITHUB_TOKEN }} 

Tagging the image using GitOps

By default, if you do not pass a tags input this action will use an algorithm based on the state of your git repo to determine the Docker image tag. This is designed to enable developers to more easily use GitOps in their CI/CD pipelines. Below is a table detailing how the GitHub trigger (branch or tag) determines the Docker tag.

Trigger	Commit SHA	Docker Tag
/refs/tags/v1.0	N/A	v1.0
/refs/heads/master	1234567	dev-1234567
/refs/heads/SOME-feature	1234567	some-feature-1234567