Part 8a: Using Earthly in your current CI

In this section, we will explore how to use Earthly in a CI system, such as GitHub Actions.

For more information on how to use Earthly in other CIs such as GitLab, Jenkins, or CircleCI, you can check out the CI Integration page.

Using Earthly in Your Current CI

To use Earthly in a CI, you typically encode the following steps in your CI's build configuration:

1. Download and install Earthly

2. Set up any credentials needed for the build

3. Log in to image registries, such as DockerHub

4. Run Earthly

As part of this, you may need to set up credentials for Earthly Cloud, if you are using Earthly Satellites or Earthly Secrets. For this, you can use the following command:

earthly account create-token my-ci-token

Finally, here is a complete example of how to run Earthly in GitHub Actions:

# .github/workflows/ci.yml

name: CI

on:
  push:
    branches: [ main ]
  pull_request:
    branches: [ main ]

jobs:
  build:
    runs-on: ubuntu-latest
    env:
      DOCKERHUB_USERNAME: ${{ vars.DOCKERHUB_USERNAME }}
      DOCKERHUB_TOKEN: ${{ secrets.DOCKERHUB_TOKEN }}
      FORCE_COLOR: 1
    steps:
    - uses: earthly/actions/setup-earthly@v1
      with:
        version: v0.8.13
    - uses: actions/checkout@v2
    - name: Docker Login
      run: docker login --username "$DOCKERHUB_USERNAME" --password "$DOCKERHUB_TOKEN"
    - name: Run build
      run: earthly --org <org-name> --sat <satellite-name> --ci --push +build

Here is an explanation of the steps above:

• The action earthly/actions/setup-earthly@v1 downloads and installs Earthly. Running this action is similar to running the Earthly installation one-liner sudo /bin/sh -c 'wget https://github.com/earthly/earthly/releases/download/v0.8.13/earthly-linux-amd64 -O /usr/local/bin/earthly && chmod +x /usr/local/bin/earthly'

• The command docker login performs a login to the DockerHub registry. This is required, to prevent rate-limiting issues when using popular base images.

• The command earthly --org ... --sat ... --ci --push +build executes the build. The --ci flag is used here, in order to force the use of --strict mode. In --strict mode, Earthly prevents the use of features that make the build less repeatable and also disables local outputs -- because artifacts and images resulting from the build are not needed within the CI environment. Any outputs should be pushed via RUN --push or SAVE IMAGE --push commands. The flags --org and --sat allow you to select the organization and satellite to use for the build. If no satellite is specified, the build will be executed in the CI environment itself, with limited caching.

For more information about integrating Earthly with other CI systems, you can check out the CI Integration page.