GitHub Action
Conditional Container Builder with Fallback
This action builds Docker/Podman containers conditionally using a set of directories. If any files were changed matching that, then build a container. If those files were not changed, retag an existing build.
This is useful in CI/CD pipelines where not every package/app needs to be rebuilt.
This tool is currently strongly opinionated and generatess images with a rigid structure below. This is intended to become more flexible in future.
Package name: <organization>/<repository>/<package>:<tag>
Pull with: docker pull ghcr.io/<organization>/<repository>/<package>:<tag>
Only GitHub Container Registry (ghcr.io) is supported so far.
- uses: bcgov-nr/action-conditional-container-builder@v1.0.0
with:
### Required
# Package name
package: frontend
# Tag name (<package>:<tag>)
tag: ${{ github.event.number }}
# Usually ${{ secrets.GITHUB_TOKEN }}, but a personal access token works too
token: ${{ secrets.GITHUB_TOKEN }}
### Typical / recommended
# Fallback tag, used if no build was generated
# Optional, defaults to nothing, which forces a build
# Non-matching or malformed tags are rejected, which also forced a build
tag_fallback: test
# Bash array to diff for build triggering
# Optional, defaults to nothing, which forces a build
triggers: ('frontend/')
# Sets the build context/directory, which containt, but not points to a Docker
# Optional, defaults to package name
build_context: ./frontend
# Sets a list of [build-time variables](https://docs.docker.com/engine/reference/commandline/buildx_build/#build-arg)
# Optional, defaults to sample content
build_args: |
ENV=build
### Usually a bad idea / not recommended
# Overrides the default branch to diff against
# Defaults to the default branch, usually `main`
diff_branch: ${{ github.event.repository.default_branch }}
# Repository to clone and process
# Useful for consuming other repos, like in testing
# Defaults to the current one
repository: ${{ github.repository }}Build a single subfolder with a Dockerfile in it. Runs on pull requests (PRs).
Create or modify a GitHub workflow, like below. E.g. ./github/workflows/pr-open.yml
name: Pull Request
on:
pull_request:
concurrency:
group: ${{ github.workflow }}-${{ github.ref }}
cancel-in-progress: true
jobs:
builds:
permissions:
packages: write
runs-on: ubuntu-22.04
steps:
- uses: actions/checkout@v3
- name: Builds
uses: bcgov-nr/action-conditional-container-builder@v1.0.0
with:
package: frontend
tag: ${{ github.event.number }}
tag_fallback: test
token: ${{ secrets.GITHUB_TOKEN }}
triggers: ('frontend/')Build an image overriding the build context, which is a directory containing a Dockerfile.
Create or modify a GitHub workflow, like below. E.g. ./github/workflows/pr-open.yml
name: Pull Request
on:
pull_request:
concurrency:
group: ${{ github.workflow }}-${{ github.ref }}
cancel-in-progress: true
jobs:
builds:
permissions:
packages: write
runs-on: ubuntu-22.04
steps:
- uses: actions/checkout@v3
- name: Builds
uses: bcgov-nr/action-conditional-container-builder@v1.0.0
with:
package: frontend
build_context: ./
tag: ${{ github.event.number }}
tag_fallback: test
token: ${{ secrets.GITHUB_TOKEN }}
triggers: ('frontend/')Build an image overriding the build context and the build file, which is the Dockerfile.
Create or modify a GitHub workflow, like below. E.g. ./github/workflows/pr-open.yml
name: Pull Request
on:
pull_request:
concurrency:
group: ${{ github.workflow }}-${{ github.ref }}
cancel-in-progress: true
jobs:
builds:
permissions:
packages: write
runs-on: ubuntu-22.04
steps:
- uses: actions/checkout@v3
- name: Builds
uses: bcgov-nr/action-conditional-container-builder@v1.0.0
with:
package: frontend
build_context: ./
build_file: subdir/Dockerfile
tag: ${{ github.event.number }}
tag_fallback: test
token: ${{ secrets.GITHUB_TOKEN }}
triggers: ('frontend/')Build from multiple subfolders with Dockerfile in them. This time an outside repository is used. Runs on pull requests (PRs).
Create or modify a GitHub workflow, like below. E.g. ./github/workflows/pr-open.yml
name: Pull Request
on:
pull_request:
concurrency:
group: ${{ github.workflow }}-${{ github.ref }}
cancel-in-progress: true
jobs:
builds:
permissions:
packages: write
runs-on: ubuntu-22.04
strategy:
matrix:
package: [backend, frontend]
include:
- package: backend
triggers: ('backend/')
- package: frontend
triggers: ('frontend/')
steps:
- uses: actions/checkout@v3
- name: Test Builds
uses: bcgov-nr/action-conditional-container-builder@v1.0.0
with:
package: ${{ matrix.package }}
tag: ${{ github.event.number }}
tag_fallback: test
repository: bcgov/nr-quickstart-typescript
token: ${{ secrets.GITHUB_TOKEN }}
triggers: ${{ matrix.triggers }}
If a build has been generated this action will output true.
- id: meaningful_id_name
uses: bcgov-nr/action-conditional-container-builder@v1.0.0
...
- if: steps.meaningful_id_name.outputs.build == 'true'
...Workflows kicked off by Dependabot or a fork run with reduced permissions. That can be addressed by setting explict permissions for the GITHUB_TOKEN. If this is not required, then remove the lines below from these examples.
permissions:
packages: write