[GitHub] Github Actions - Workflow dependencies

 Github Action   Workflow   Dependency 

 

▌Introduction

---

 

The jobs in a GitHub Actions: workflow by default run in parallel at the same time.

To run a job only when another job has completed, we can use needs keyword as following,

 

(The sample manifest comes from GitHub Docs: Creating dependent jobs)

jobs:

  setup:

    runs-on: ubuntu-latest

    steps:

      - run: ./setup_server.sh

  build:

    needs: setup

    runs-on: ubuntu-latest

    steps:

      - run: ./build_server.sh

  test:

    needs: build

    runs-on: ubuntu-latest

    steps:

      - run: ./test_server.sh

 

However, it needs some tricks on workflows dependencies, let us see the following example.

 

 

▌Implement

---

▋ Scenario

I am going to create 2 workflows:

1.  Publish Docker Image

2.  Run Docker Container (to execute some commands)

 

The second workflow depends on the result of the first one.

We will run the container after the Docker image publish successfully. In other words, if publishing fails, we won’t run the container.

 

▋ Constraints

 

1.  Currently (2021-11) GitHub Actions only supports putting the second workflow (that will be triggered by first one) on the “default branch”.

2.  To get the previous workflow’s state, use the value of github.event.workflow_run.conclusion.

 

 

▋ Workflow: Publish Docker Image

 

This is the first workflow and it is not what we will focus in the article, see [GitHub] Github Actions - Publish Docker images for more details.

 

▋publish_docker_image.yml

---

name: Publish Docker Image

on:

  push:

    branches: [ master ]

jobs:

  push_images_to_acr:

    name: Push images to ACR

    runs-on: ubuntu-18.04

    steps:

      - name: Checkout repo

        uses: actions/checkout@v2

      - name: Login to ACR

        uses: azure/docker-login@v1

        with:

          login-server: ${{ secrets.ACR_REGISTRY }}

          username: ${{ secrets.ACR_USERNAME }}

          password: ${{ secrets.ACR_PASSWORD }}

      - name: Build and push

        id: build_publish

        uses: docker/build-push-action@v2

        with:

          # context: .

          file: ./docker/dockerfile

          push: true

          tags: ${{ secrets.ACR_REGISTRY }}/my-demo:latest

 

 

 

▋ Workflow: Run Docker Container

The second workflow will need to watch the if the dependent workflow has been closed by

on:

  workflow_run:

    workflows:

      - The dependent workflow name

    types:

      - completed

 

▋run_docker_constainer.yml

---

name: Run Docker Container

on:

  workflow_run:

    workflows:

      - Publish Docker Image

    types:

      - completed

jobs:

  run_docker_container:

    name: Run

    if: ${{ github.event.workflow_run.conclusion == 'success' }}

    runs-on: ubuntu-18.04

    steps:

      - name: Run

        uses: addnab/docker-run-action@v3

        with:

          username: ${{ secrets.ACR_USERNAME }}

          password: ${{ secrets.ACR_PASSWORD }}

          registry: ${{ secrets.ACR_REGISTRY }}

          image: ${{ secrets.ACR_REGISTRY }}/my-demo:latest

          # options:

          run: |

            echo "The container is running."

 

Like we mentioned in Constraints, we have to enable the workflow (put the manifest file) in the default branch, e.q. master or main.

Notice that the above manifest used addnab/docker-run-action as the “Docker Run Action” Or we can use the default Action like this,

---

name: Run Docker Container

on:

  workflow_run:

    workflows:

      - Publish Docker Image

    types:

      - completed

jobs:

  run_docker_container:

    name: Run

    if: ${{ github.event.workflow_run.conclusion == 'success' }}

    runs-on: ubuntu-18.04

    container: karatejb/my-demo:latest

    steps:

      - name: Dcoker run

        run: |

          echo "The container is running."

 

 

▌Reference

---

▋GitHub Docs: workflow_run

▋addnab/docker-run-action

▋Using Docker Containers In Jobs - GitHub Actions

▋Workflow_run not working as expected

▋How to use the GitHub Actions `workflow_run` event?

▋actions/runner: Secrets cannot be used to condition job runs #520

▋Pass Github secrets to a docker github action

▋Workflow_run completed event triggered by failed workflow