Demo Composite Actions

• Create a composite action (action.yaml) in your repo.
• Call that composite action from a workflow with uses: ./....
• Troubleshoot the common “could not find action.yaml” error.
• Run a single workflow manually (useful when testing).

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1. Create a composite action

1. At the root of your repository create a folder named composite-action.
2. Inside that folder add an action.yaml file with the following contents:

name: "Setup Environment"
description: "A simple composite action"
inputs:
  environment:
    required: true
runs:
  using: "composite"
  steps:
    - run: echo "Setting up ${{ inputs.environment }}"
      shell: bash
    - run: echo "Running linter..."
      shell: bash

• inputs.environment is declared as required so callers must provide a value.
• runs.using: "composite" tells GitHub this action is a composite action, composed of the listed steps.
• Replace the sample echo steps with real tasks (install dependencies, run linters, run tests, etc.) as appropriate for your project.

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2. Use the composite action in a workflow

name: Using Composite Workflow

on:
  push:
  workflow_dispatch:

jobs:
  test-composite-action:
    runs-on: ubuntu-latest
    steps:
      - uses: actions/checkout@v4
      - uses: ./composite-action
        with:
          environment: production

• When referencing a composite action stored in the same repository, use a relative path such as uses: ./composite-action.
• Provide the with: map to pass required inputs (here, environment).

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3. When committing

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Run a single workflow manually

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4. Troubleshooting

• The folder name used in your workflow matches the actual folder name in the repository (for example, ./composite-action).
• action.yaml (or action.yml) exists at that path and is committed to the branch the workflow runs on.
• The workflow runs on the branch where action.yaml was committed.

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5. Example runner log (successful run)

test-composite-action
succeeded in 6s

Set up job
Run actions/checkout@v4
Run ./composite-action

1  Prepare all required actions
2  ▸ Run ./composite-action
5  ▾ Run echo "Setting up production"
6  ▸ Run echo "Setting up production"
9      Setting up production
10 ▾ Run echo "Running linter..."
11 ▸ Run echo "Running linter..."
14     Running linter...

Post Run actions/checkout@v4
Complete job

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Further reading & references

• GitHub Actions: Reusing workflows and composite actions
• GitHub Actions: Creating composite actions