Github Actions – trigger another action after one action is completed

There are 2 options of doing this:

1. Use a second job inside the same workflow.yml together with the needs keyword
2. Create a separate notify.yml workflow that uses the workflow_run event as a trigger

---

1. Same workflow, separate job with needs keyword

In your workflow.yml file you simply define two jobs like this (leveraging the needs: build configuration in the second job):

name: CI build and notify

on: [push]

jobs:
  build:
    runs-on: ubuntu-latest

    steps:
    - uses: actions/checkout@v2
    
    - name: Deploy Docker image to Google Cloud Run
      run: ...

  notify:
    needs: build
    runs-on: ubuntu-latest

    steps:
      - uses: actions/checkout@v2

      - name: Notify Slack and send eMail
        run: ...

As the docs state, the second notify job will only start if the first build job succeeded:

Identifies any jobs that must complete successfully before this job
will run.

Here’s a screenshot of how this approach can look like practically from my own project (I have a second publish-snapshot job instead of your notify job – but the concept stays the same):

There’s also a way to always let the notify job run, even if the build job failed. You have to enhance the needs with a if: always() configuration then.

---

2. Separate workflow, using the workflow_run event as a trigger

Using the workflow_run event as a trigger we end up having 2 separate GitHub Actions workflow yaml files:

build.yml

name: CI build

on: [push]

jobs:
  build:
    runs-on: ubuntu-latest

    steps:
    - uses: actions/checkout@v2

    - name: Deploy Docker image to Google Cloud Run
      run: ...

notify.yml

name: CI notify

# Only trigger, when the build workflow succeeded
on:
  workflow_run:
    workflows: ["CI build"]
    types:
      - completed

jobs:
  notify:
    runs-on: ubuntu-latest

    steps:
      - uses: actions/checkout@v2

      - name: Notify Slack and send eMail
        run: ...

A crucial point here is that the name: CI build definition of the first yaml file must exactly match the workflow_run: workflows: ["CI build"] definition in the second yaml file. Another point is that this approach needs to be done on the default branch (which is mostly main or master) as the docs state:

Note: This event will only trigger a workflow run if the workflow file
is on the default branch.

Here’s also a full example project using the 1st option if you’re interested.