Persisting workflow data using artifacts

Artifacts allow you to share data between jobs in a workflow and store data once that workflow has completed.

GitHub Actions is available with GitHub Free, GitHub Pro, GitHub Team, and GitHub Enterprise Cloud. For more information, see "GitHub's products."

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About workflow artifacts

Artifacts allow you to persist data after a job has completed. An artifact is a file or collection of files produced during a workflow run. You can use artifacts to pass data between jobs in a workflow or persist build and test output after a workflow run has ended. GitHub stores artifacts for 90 days for pushes and pull requests. The retention period for a pull request restarts each time someone pushes new commits to the pull request.

Storing artifacts uses storage space on GitHub. GitHub Actions usage is free for public repositories. For private repositories, each GitHub account receives a certain amount of free minutes and storage, depending on the product used with the account. For more information, see "Managing billing for GitHub Actions."

You must upload artifacts during a workflow run. GitHub provides two actions that you can use to upload and download build artifacts. Files uploaded to a workflow run are archived using the .zip format. For more information, see the actions/upload-artifact and download-artifact actions.

Each job in a workflow runs in a fresh instance of the virtual environment. When the job completes, the runner terminates and deletes the instance of the virtual environment.

To share data between jobs:

  • You can upload the data before the job ends to save the file inside the workflow run. When you upload an archive, you must give it a name.
  • After uploading a file, you can download it in another job within the same workflow run. When you download an archive, you can reference the archive by name. You can only download artifacts that were uploaded during the same workflow run.

Steps that are part of a job run in the same virtual environment, but run in their own individual processes. To pass data between steps in a job, you can use inputs and outputs. For more information about inputs and outputs, see "Metadata syntax for GitHub Actions."

These are some of the common build and test output artifacts that you might want to upload:

  • Log files and core dumps
  • Test results, failures, and screenshots
  • Binary or archive files
  • Stress test performance output and code coverage results

Passing data between jobs in a workflow

You can use the upload-archive and download-archive actions to share data between jobs in a workflow. This example workflow illustrates how to pass data between jobs in the same workflow. For more information, see the actions/upload-artifact and download-artifact actions.

Jobs that are dependent on a previous job's artifacts must wait for the dependent job to complete successfully. This workflow uses the needs keyword to ensure that job_1, job_2, and job_3 run sequentially. For example, job_2 requires job_1 using the needs: job_1 syntax.

Job 1 performs these steps:

  • Adds the values 3 and 7 and outputs the value to a text file called math-homework.txt.
  • Uses the upload-artifact action to upload the math-homework.txt file with the name homework. The action places the file in a directory named homework.

Job 2 uses the result in the previous job:

  • Downloads the homework artifact uploaded in the previous job. By default, the download-artifact action downloads artifacts to the workspace directory that the step is executing in. You can specify a different directory to download the action to using the path input parameter.
  • Reads the value in the homework/math-homework.txt file and multiplies the value by 9 and then updates the file with the new value.
  • Uploads the math-homework.txt file. This upload overwrites the previous upload because both of the uploads share the same name.

Job 3 displays the result uploaded in the previous job:

  • Downloads the homework artifact.
  • Prints the result of the math equation to the log.

The full math operation performed in this workflow example is (3 + 7) x 9 = 90.

name: Share data between jobs

on: [push]

jobs:
  job_1:
    name: Add 3 and 7
    runs-on: ubuntu-latest
    steps:
      - shell: bash
        run: |
          expr 3 + 7 > math-homework.txt
      - name: Upload math result for job 1
        uses: actions/upload-artifact@v1
        with:
          name: homework
          path: math-homework.txt

  job_2:
    name: Multiply by 9
    needs: job_1
    runs-on: windows-latest
    steps:
      - name: Download math result for job 1
        uses: actions/download-artifact@v1
        with:
          name: homework
      - shell: bash
        run: |
          value=`cat homework/math-homework.txt`
          expr $value \* 9 > homework/math-homework.txt
      - name: Upload math result for job 2
        uses: actions/upload-artifact@v1
        with:
          name: homework
          path: homework/math-homework.txt

  job_3:
    name: Display results
    needs: job_2
    runs-on: macOS-latest
    steps:
      - name: Download math result for job 2
        uses: actions/download-artifact@v1
        with:
          name: homework
      - name: Print the final result
        shell: bash
        run: |
          value=`cat homework/math-homework.txt`
          echo The result is $value

Workflow that passes data between jobs to perform math

Sharing data between workflow runs

After a workflow ends, you can download an archive of the uploaded artifacts on GitHub by finding the workflow run in the Actions tab. GitHub does not currently offer a REST API to retrieve uploaded artifacts.

If you need to access artifacts from a previously run workflow, you'll need to store the artifacts somewhere. For example, you could run a script at the end of your workflow to store build artifacts on Amazon S3 or Artifactory, and then use the storage service's API to retrieve those artifacts in a future workflow.

Uploading build and test artifacts

You can create a continuous integration (CI) workflow to build and test your code in a GitHub-hosted virtual environment. For more information about using GitHub Actions to perform CI, see About continuous integration.

The output of building and testing your code often produces files you can use to debug test failures and production code that you can deploy. You can configure a workflow to build and test the code pushed to your repository and report a success or failure status. You can upload the build and test output to use for deployments, debugging failed tests or crashes, and viewing test suite coverage.

You can use the upload-archive action to upload artifacts. For more information, see the actions/upload-artifact action.

Example

For example, your repository or a web application might contain SASS and Typescript files that you must compile to CSS and JavaScript. Assuming your build configuration outputs the compiled files in the dist directory, you would deploy the files in the dist directory to your web application server if all tests completed successfully.

|-- hello-world (repository)
|   └── dist
|   └── tests
|   └── src
|       └── sass/app.scss
|       └── app.ts
|   └── output
|       └── test
|   

This example shows you how to create a workflow for a Node.js project that builds the code in the src directory and runs the tests in the tests directory. You can assume that running npm test produces a code coverage report named code-coverage.html stored in the output/test/ directory.

The workflow uploads the production artifacts in the dist directory and the code-coverage.html as two separate artifacts.

name: Node CI

on: [push]

jobs:
  build_and_test:
    runs-on: ubuntu-latest
    steps:
      - name: Checkout repository
        uses: actions/checkout@v1
      - name: npm install, build, and test
        run: |
          npm install
          npm run build --if-present
          npm test
      - name: Archive production artifacts
        uses: actions/upload-artifact@v1
        with:
          name: dist
          path: dist
      - name: Archive code coverage results
        uses: actions/upload-artifact@v1
        with:
          name: code-coverage-report
          path: output/test/code-coverage.html

Image of workflow upload artifact workflow run

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