Github Actions - trigger another action after one action is completed

Question

I have one action (a yaml file) for deploying a docker image to Google Cloud Run.

I would like to receive Slack or Email messages informing the build and push results.

How could the message action be triggered after build action is completed?

Is it possible to get the result of the build action?

Kauppi

Answer 1

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.

Tufts

The first approach (with same workflow, separate job with needs keyword) would not address the problem described: I would like to receive Slack or Email messages informing the build results as the dependent notify job will only be triggered when the build job succeeds but will not be triggered when it fails. – Deafmute

Yeah, but as I wrote beneath the first approaches screenshot: "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." So using if: always() right before the needs: build will do the trick also with the first approach. – Tufts

I would use workflow_dispatch rather than using workflow_run... Depends on the control u need when calling notify.yml... if I need to supply some values the next workflow i don't think it's possible via workflow_run... – Pharmacology

workflow_dispatch is a action you need to manually trigger. That's an interesting approach I use myself in other contexts (e.g. release processes) - see this example github.com/jonashackt/github-actions-release-maven . But I guess it's not relevant in this very Q&A since the question was: "How could the message action be triggered after build action is completed?". This can't be done with the workflow_dispatch event because of it's manual nature. – Tufts

Note that workflow_run: completed works regardless of upstream workflow failed or not. – Antonetta

Per docs.github.com/en/actions/reference/… you need to add if: ${{ github.event.workflow_run.conclusion == 'success' }} if you only want to trigger the workflow on the success of the first. – Wenz

Doea the second approach runs the workflows in different hardware or they are the same? Are the changes made with the first workflow are applied when the second runs? – Oly

By different hardware you mean different virtual machine I guess? Yeah, using the second approach with 2 separate GitHub workflows will result in 2 separate VMs booted up. If you setup tools or prepare things on VM 1, they will not be available on VM 2. – Tufts

Answer 2

The best method i've found for reusable workflows in the same repository is https://docs.github.com/en/actions/using-workflows/reusing-workflows

In the workflow you want to re-use (let's call it wf1):

# wf1.yml
on:
  workflow_call:

In the workflow you want to call wf1 from (let's call this wf2)

# wf2.yml
jobs:
  call-wf1:
    uses: ./.github/workflows/wf1.yml
    secrets: inherit

---

In order to get data from one workflow to another, check out https://docs.github.com/en/actions/using-workflows/reusing-workflows#using-outputs-from-a-reusable-workflow.

First, set up your reusable workflow to output the data:

name: Reusable workflow

on:
  workflow_call:
    # Map the workflow outputs to job outputs
    outputs:
      firstword:
        description: "The first output string"
        value: ${{ jobs.example_job.outputs.output1 }}
      secondword:
        description: "The second output string"
        value: ${{ jobs.example_job.outputs.output2 }}

jobs:
  example_job:
    name: Generate output
    runs-on: ubuntu-latest
    # Map the job outputs to step outputs
    outputs:
      output1: ${{ steps.step1.outputs.firstword }}
      output2: ${{ steps.step2.outputs.secondword }}
    steps:
      - id: step1
        run: echo "::set-output name=firstword::hello"
      - id: step2
        run: echo "::set-output name=secondword::world"

Now use it in the calling workflow:

name: Call a reusable workflow and use its outputs

on:
  workflow_dispatch:

jobs:
  job1:
    # local repo
    # uses: ./.github/workflows/called-workflow.yml@v1
    # other repo
    uses: octo-org/example-repo/.github/workflows/called-workflow.yml@v1

  job2:
    runs-on: ubuntu-latest
    needs: job1
    steps:
      - run: echo ${{ needs.job1.outputs.firstword }} ${{ needs.job1.outputs.secondword }}

Nail

All the other methods require way too much setup and work. – Nail

Also, here's an example using this method: github.com/ipfs/ipfs-webui/blob/main/.github/workflows/…. This particular workflow is called on a schedule or manually via the github UI. – Nail

Worth mentioning, do NOT use runs-on on the same job that you called the workflow with uses – Donalddonaldson

Ah, secrets: inherit. It just saved me from banging my head after 2 weeks of debugging without searching the internet. Upvoted! – Blatherskite

Local repo paths must start with ./ and may not reference versions – Zoography

The uses should be directly under the job. Not inside steps like I like an idiot did for several minutes :facepalm:. – Isogonic

Worth noting that matrix strategies will require you to specify flow2's inputs rather than specifying flow1's outputs. – Igor

@MikeB would you mind adding a section to clarify what you mean? – Nail

Answer 3

First, you are mixing terms here. According to GitHub Actions documentation a single YAML file is called a workflow (not an action) and consists of jobs. Jobs contain a sequence of steps (including actions) that are executed one after another. A particular workflow execution is called a run. Having that in mind lets go the questions.

How could the message workflow be triggered after build workflow is completed?

You can use GitHub API to trigger a webhook event called repository_dispatch (only for the base branch) or workflow_dispatch. This can be easily done using a dedicated Repository Dispach action in your build workflow.

Is it possible to get the result of the build workflow?

Yes, the result of the workflow run can be obtained using given GitHub API

But if you only want to send the build result notification of the currently executed workflow you don't need to create a separate workflow and trigger it from the parent. You can use dedicated Slack actions or e-mail actions.

Groth

An example how the ymls would look would be great :) – Sonnysonobuoy

Answer 4

you can try in step 2 the following directive:

needs: step-1-job-name 

just after job name

Kirovabad

Is there a way to check multiple jobs success? – Spiritualist

Yes, Vaulstein: "needs: [job1, job2]" See docs.github.com/en/actions/learn-github-actions/… – Dukedom

Answer 5

How could the message action be triggered after build action is completed?

This should now (August 2020) be possible with "GitHub Actions improvements for fork and pull request workflows"

Another frequently-requested feature for Actions is a way to trigger one workflow based on the completion of another workflow.
For example, you may want to take the results of a CI workflow and run some further analysis.

The new workflow_run event enables you to trigger a new workflow when one or more workflows are requested or completed.
Runs triggered by the workflow_run event always use the default branch for the repository, and have access to a read/write token as well as secrets.
As an example, as a maintainer you could set up a workflow that takes the artifacts generated by the pull request workflow, do some analysis, and post comments back to the pull request.
This event is also available as a web hook.

Seethe