https://github.com/jonashackt/custom-github-action
Project showing how to create & use your own GitHub Action
https://github.com/jonashackt/custom-github-action
Last synced: 4 months ago
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Project showing how to create & use your own GitHub Action
- Host: GitHub
- URL: https://github.com/jonashackt/custom-github-action
- Owner: jonashackt
- License: mit
- Created: 2021-03-19T07:55:41.000Z (about 5 years ago)
- Default Branch: main
- Last Pushed: 2021-03-19T10:54:38.000Z (about 5 years ago)
- Last Synced: 2025-10-10T09:09:00.666Z (8 months ago)
- Size: 288 KB
- Stars: 1
- Watchers: 1
- Forks: 1
- Open Issues: 0
-
Metadata Files:
- Readme: README.md
- License: LICENSE
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README
# custom-github-action
Project showing how to create & use your own GitHub Action
## 1. Create a custom GitHub Action
In order to reuse GitHub Actions workflow snippets let's create a custom GitHub Action (see https://docs.github.com/en/actions/creating-actions/about-actions).
As we need some sort of example, let's use the https://github.com/jonashackt/spring-boot-buildpack project, which uses the following [GitHub Action workflow](https://github.com/jonashackt/spring-boot-buildpack/blob/main/.github/workflows/build.yml) - which is also referred to on stackoverflow https://stackoverflow.com/questions/66598692/cache-cloud-native-buildpacks-paketo-io-pack-cli-builds-on-github-actions-e-g/66598693#66598693:
```yaml
name: build
on: [push]
jobs:
build-with-paketo-push-2-dockerhub:
runs-on: ubuntu-latest
steps:
- uses: actions/checkout@v2
- name: Login to DockerHub Container Registry
run: echo $DOCKER_HUB_TOKEN | docker login -u jonashackt --password-stdin
env:
DOCKER_HUB_TOKEN: ${{ secrets.DOCKER_HUB_TOKEN }}
- name: Install pack CLI via the official buildpack Action https://github.com/buildpacks/github-actions#setup-pack-cli-action
uses: buildpacks/github-actions/setup-pack@v4.1.0
- name: Build app with pack CLI using Buildpack Cache image (see https://buildpacks.io/docs/app-developer-guide/using-cache-image/) & publish to Docker Hub
run: |
pack build index.docker.io/jonashackt/spring-boot-buildpack:latest \
--builder paketobuildpacks/builder:base \
--path . \
--cache-image index.docker.io/jonashackt/spring-boot-buildpack-paketo-cache-image:latest \
--publish
```
So the idea is to create a custom GitHub Action that does all the 3 steps of logging into a container registry, installing Paketo.io pack CLI and building with pack CLI in one step.
### Create GitHub repository for your GitHub Action
Therefore let's create a new repository for our GitHub Action:
Now we clone the repo and create a action metadata file. But how to...
### Do multiple steps inside one Action
There's the `composite run steps action` feature https://docs.github.com/en/actions/creating-actions/creating-a-composite-run-steps-action, which was announced here https://github.com/actions/runner/issues/646:
> We’ve also heard from our community that many developers want to reuse parts of their workflows into other workflows. This new action type, composite run steps, can help developers do just that!
So using multiple steps inside one Action could be achieved using the `using: "composite"` configuration parameter inside an Action:
```yaml
runs:
using: "composite"
steps:
- run: echo Hello ${{ inputs.who-to-greet }}.
shell: bash
- run: ${{ github.action_path }}/goodbye.sh
shell: bash
```
### Reuse an Action from a custom Action?
https://stackoverflow.com/questions/58860769/call-a-github-action-from-another-github-action
https://stackoverflow.com/questions/58611841/how-can-i-reference-other-actions-from-my-github-actions-action-yml-file
This feature is still under development and should be released somewhere in 2021:
https://github.com/actions/runner/issues/646
> So right now, we can reuse other Actions inside our Action :(
### Create action.yml
Let's finally create the `action.yml` (see https://docs.github.com/en/actions/creating-actions/creating-a-composite-run-steps-action#creating-an-action-metadata-file):
```yaml
name: 'Paketo Build with pack CLI & push to registry'
description: 'Build and publish OCI container image using Cloud Native Buildpacks / Paketo.io in GitHub Actions'
author: 'jonas.hecht@codecentric.de'
inputs:
pack-version:
description: 'The version of pack to install'
required: false
default: '0.17.0'
runs:
using: "composite"
steps:
# Reusing the great pack CLI installation from https://github.com/buildpacks/github-actions/blob/main/setup-pack/action.yml
# As of https://github.com/actions/runner/issues/646 we can't simply reuse the Action, but if thats possible, we should do it :)
- name: Setup pack CLI
shell: bash
run: |
#!/usr/bin/env bash
set -euo pipefail
mkdir -p "${HOME}"/bin
echo "PATH=${HOME}/bin:${PATH}" >> "${GITHUB_ENV}"
PACK_VERSION=${{ inputs.pack-version }}
echo "Installing pack ${PACK_VERSION}"
curl \
--show-error \
--silent \
--location \
"https://github.com/buildpacks/pack/releases/download/v${PACK_VERSION}/pack-v${PACK_VERSION}-linux.tgz" \
| tar -C "${HOME}/bin" -xz pack
- name: Say hello
shell: bash
run: echo "pack CLI is ready now!"
```
### Releasing and Testing our Action
https://docs.github.com/en/actions/creating-actions/about-actions#choosing-a-location-for-your-action
## How to reuse GitHub Action workflows - or have private Actions
GitHub Actions Centrally managed workflow templates feature: https://github.com/github/roadmap/issues/98
https://stackoverflow.com/questions/60544181/how-to-us-snippets-in-github-action-workflow-file-to-avoid-duplicates
Why not use the actions/checkout Action to checkout the repository itself - and then also another repository containing an Action
https://github.com/actions/checkout#checkout-multiple-repos-side-by-side
and then use https://docs.github.com/en/actions/creating-actions/about-actions#choosing-a-location-for-your-action
with
> If you're building an action that you don't plan to make available to the public, you can store the action's files in any location in your repository. If you plan to combine action, workflow, and application code in a single repository, we recommend storing actions in the .github directory. For example, .github/actions/action-a and .github/actions/action-b.
```
jobs:
my_first_job:
steps:
- name: Checkout
uses: actions/checkout@v2
with:
path: main
- name: Checkout tools repo
uses: actions/checkout@v2
with:
repository: my-org/my-tools
path: my-tools
- name: Use local my-action
uses: ./.github/actions/my-action
```