upload-artifact/README.md

# `@actions/download-artifact`

Upload [Actions Artifacts](https://docs.github.com/en/actions/using-workflows/storing-workflow-data-as-artifacts) from your Workflow Runs. Internally powered by [@actions/artifact](https://github.com/actions/toolkit/tree/main/packages/artifact) package.

See also [download-artifact](https://github.com/actions/download-artifact).

- [`@actions/download-artifact`](#actionsdownload-artifact)
  - [v4 - What's new](#v4---whats-new)
    - [Improvements](#improvements)
    - [Breaking Changes](#breaking-changes)
  - [Usage](#usage)
    - [Inputs](#inputs)
    - [Outputs](#outputs)
  - [Examples](#examples)
    - [Upload an Individual File](#upload-an-individual-file)
    - [Upload an Entire Directory](#upload-an-entire-directory)
    - [Upload using a Wildcard Pattern](#upload-using-a-wildcard-pattern)
    - [Upload using Multiple Paths and Exclusions](#upload-using-multiple-paths-and-exclusions)
    - [Customization if no files are found](#customization-if-no-files-are-found)
    - [(Not) Uploading to the same artifact](#not-uploading-to-the-same-artifact)
    - [Environment Variables and Tilde Expansion](#environment-variables-and-tilde-expansion)
    - [Retention Period](#retention-period)
    - [Using Outputs](#using-outputs)
      - [Example output between steps](#example-output-between-steps)
      - [Example output between jobs](#example-output-between-jobs)
  - [Where does the upload go?](#where-does-the-upload-go)
  - [Additional Documentation](#additional-documentation)


## v4 - What's new

> [!IMPORTANT]
> upload-artifact@v4+ is not currently supported on GHES yet. If you are on GHES, you must use [v3](https://github.com/actions/upload-artifact/releases/tag/v3).

The release of upload-artifact@v4 and download-artifact@v4 are major changes to the backend architecture of Artifacts. They have numerous performance and behavioral improvements.

For more information, see the [`@actions/artifact`](https://github.com/actions/toolkit/tree/main/packages/artifact) documentation.

### Improvements

1. Uploads are significantly faster, upwards of 90% improvement in worst case scenarios.
2. Once uploaded, an Artifact ID is returned and Artifacts are immediately available in the UI and [REST API](https://docs.github.com/en/rest/actions/artifacts). Previously, you would have to wait for the run to be completed before an ID was available or any APIs could be utilized.
3. The contents of an Artifact are uploaded together into an _immutable_ archive. They cannot be altered by subsequent jobs. Both of these factors help reduce the possibility of accidentally corrupting Artifact files.

### Breaking Changes

1. On self hosted runners, additional [firewall rules](https://github.com/actions/toolkit/tree/main/packages/artifact#breaking-changes) may be required.
2. Uploading to the same named Artifact multiple times.

    Due to how Artifacts are created in this new version, it is no longer possible to upload to the same named Artifact multiple times. You must either split the uploads into multiple Artifacts with different names, or only upload once. Otherwise you _will_ encounter an error.

3. Limit of Artifacts for an individual job. Each job in a workflow run now has a limit of 10 artifacts.

## Usage

### Inputs

```yaml
- uses: actions/download-artifact@v4
  with:
    # Name of the artifact to upload.
    # Optional. Default is 'artifact'
    name:

    # A file, directory or wildcard pattern that describes what to upload
    # Required.
    path:

    # The desired behavior if no files are found using the provided path.
    # Available Options:
    #   warn: Output a warning but do not fail the action
    #   error: Fail the action with an error message
    #   ignore: Do not output any warnings or errors, the action does not fail
    # Optional. Default is 'warn'
    if-no-files-found:

    # Duration after which artifact will expire in days. 0 means using default retention.
    # Minimum 1 day.
    # Maximum 90 days unless changed from the repository settings page.
    # Optional. Defaults to repository settings.
    retention-days:

    # The level of compression for Zlib to be applied to the artifact archive.
    # The value can range from 0 to 9.
    # For large files that are not easily compressed, a value of 0 is recommended for significantly faster uploads.
    # Optional. Default is '6'
    compression-level:
```

### Outputs

| Name | Description | Example |
| - | - | - |
| `artifact-id` | GitHub ID of an Artifact, can be used by the REST API | `1234` |

## Examples

### Upload an Individual File

```yaml
steps:
- run: mkdir -p path/to/artifact
- run: echo hello > path/to/artifact/world.txt
- uses: actions/upload-artifact@v4
  with:
    name: my-artifact
    path: path/to/artifact/world.txt
```

### Upload an Entire Directory

```yaml
- uses: actions/upload-artifact@v4
  with:
    name: my-artifact
    path: path/to/artifact/ # or path/to/artifact
```

### Upload using a Wildcard Pattern

```yaml
- uses: actions/upload-artifact@v4
  with:
    name: my-artifact
    path: path/**/[abc]rtifac?/*
```

### Upload using Multiple Paths and Exclusions

```yaml
- uses: actions/upload-artifact@v4
  with:
    name: my-artifact
    path: |
      path/output/bin/
      path/output/test-results
      !path/**/*.tmp      
```

For supported wildcards along with behavior and documentation, see [@actions/glob](https://github.com/actions/toolkit/tree/main/packages/glob) which is used internally to search for files.

If a wildcard pattern is used, the path hierarchy will be preserved after the first wildcard pattern:

```
path/to/*/directory/foo?.txt =>
    ∟ path/to/some/directory/foo1.txt
    ∟ path/to/some/directory/foo2.txt
    ∟ path/to/other/directory/foo1.txt

would be flattened and uploaded as =>
    ∟ some/directory/foo1.txt
    ∟ some/directory/foo2.txt
    ∟ other/directory/foo1.txt
```

If multiple paths are provided as input, the least common ancestor of all the search paths will be used as the root directory of the artifact. Exclude paths do not affect the directory structure.

Relative and absolute file paths are both allowed. Relative paths are rooted against the current working directory. Paths that begin with a wildcard character should be quoted to avoid being interpreted as YAML aliases.

### Customization if no files are found

If a path (or paths), result in no files being found for the artifact, the action will succeed but print out a warning. In certain scenarios it may be desirable to fail the action or suppress the warning. The `if-no-files-found` option allows you to customize the behavior of the action if no files are found:

```yaml
- uses: actions/upload-artifact@v4
  with:
    name: my-artifact
    path: path/to/artifact/
    if-no-files-found: error # 'warn' or 'ignore' are also available, defaults to `warn`
```

### (Not) Uploading to the same artifact

Unlike earlier versions of `upload-artifact`, uploading to the same artifact via multiple jobs is _not_ supported with `v4`.

```yaml
- run: echo hi > world.txt
- uses: actions/upload-artifact@v4
  with:
    # implicitly named as 'artifact'
    path: world.txt

- run: echo howdy > extra-file.txt
- uses: actions/upload-artifact@v4
  with:
    # also implicitly named as 'artifact', will fail here!
    path: extra-file.txt
```

Artifact names must be unique since each created artifact is idempotent so multiple jobs cannot modify the same artifact.

In matrix scenarios, be careful to not accidentally upload to the same artifact, or else you will encounter conflict errors. It would be best to name the artifact _with_ a prefix or suffix from the matrix:

```yaml
jobs:
  upload:
    name: Generate Build Artifacts

    strategy:
      matrix:
        os: [ubuntu-latest, windows-latest]
        version: [a, b, c]

    runs-on: ${{ matrix.os }}

    steps:
    - name: Build
      run: ./some-script --version=${{ matrix.version }} > my-binary
    - name: Upload
      uses: actions/upload-artifact@v4
      with:
        name: binary-${{ matrix.os }}-${{ matrix.version }}
        path: my-binary
```

This will result in artifacts like: `binary-ubuntu-latest-a`, `binary-windows-latest-b`, and so on.

Previously the behavior _allowed_ for the artifact names to be the same which resulted in unexpected mutations and accidental corruption. Artifacts created by upload-artifact@v4 will be immutable.

### Environment Variables and Tilde Expansion

You can use `~` in the path input as a substitute for `$HOME`. Basic tilde expansion is supported:

```yaml
  - run: |
      mkdir -p ~/new/artifact
      echo hello > ~/new/artifact/world.txt      
  - uses: actions/upload-artifact@v4
    with:
      name: Artifacts-V4-beta
      path: ~/new/**/*
```

Environment variables along with context expressions can also be used for input. For documentation see [context and expression syntax](https://help.github.com/en/actions/reference/context-and-expression-syntax-for-github-actions):

```yaml
    env:
      name: my-artifact
    steps:
    - run: |
        mkdir -p ${{ github.workspace }}/artifact
        echo hello > ${{ github.workspace }}/artifact/world.txt        
    - uses: actions/upload-artifact@v4
      with:
        name: ${{ env.name }}-name
        path: ${{ github.workspace }}/artifact/**/*
```

For environment variables created in other steps, make sure to use the `env` expression syntax

```yaml
    steps:
    - run: |
        mkdir testing
        echo "This is a file to upload" > testing/file.txt
        echo "artifactPath=testing/file.txt" >> $GITHUB_ENV        
    - uses: actions/upload-artifact@v4
      with:
        name: artifact
        path: ${{ env.artifactPath }} # this will resolve to testing/file.txt at runtime
```

### Retention Period

Artifacts are retained for 90 days by default. You can specify a shorter retention period using the `retention-days` input:

```yaml
  - name: Create a file
    run: echo "I won't live long" > my_file.txt

  - name: Upload Artifact
    uses: actions/upload-artifact@v4
    with:
      name: my-artifact
      path: my_file.txt
      retention-days: 5
```

The retention period must be between 1 and 90 inclusive. For more information see [artifact and log retention policies](https://docs.github.com/en/free-pro-team@latest/actions/reference/usage-limits-billing-and-administration#artifact-and-log-retention-policy).

### Using Outputs

If an artifact upload is successful then an `artifact-id` output is available. This ID is a unique identifier that can be used with [Artifact REST APIs](https://docs.github.com/en/rest/actions/artifacts).

#### Example output between steps

```yml
    - uses: actions/upload-artifact@v4
      id: artifact-upload-step
      with:
        name: my-artifact
        path: path/to/artifact/content/

    - name: Output artifact ID
      run:  echo 'Artifact ID is ${{ steps.artifact-upload-step.outputs.artifact-id }}'
```

#### Example output between jobs

```yml
jobs:
  job1:
    runs-on: ubuntu-latest
    outputs:
      output1: ${{ steps.my-artifact.outputs.artifact-id }}
    steps:
      - uses: actions/upload-artifact@v4
        id: artifact-upload-step
        with:
          name: my-artifact
          path: path/to/artifact/content/
  job2:
    runs-on: ubuntu-latest
    needs: job1
    steps:
      - env:
          OUTPUT1: ${{needs.job1.outputs.output1}}
        run: echo "Artifact ID from previous job is $OUTPUT1"
```

## Where does the upload go?

At the bottom of the workflow summary page, there is a dedicated section for artifacts. Here's a screenshot of something you might see:

<img src="https://user-images.githubusercontent.com/16109154/103645952-223c6880-4f59-11eb-8268-8dca6937b5f9.png" width="700" height="300">

There is a trashcan icon that can be used to delete the artifact. This icon will only appear for users who have write permissions to the repository.

The size of the artifact is denoted in bytes. The displayed artifact size denotes the size of the zip that `upload-artifact` creates during upload.

## Additional Documentation

See [Storing workflow data as artifacts](https://docs.github.com/en/actions/advanced-guides/storing-workflow-data-as-artifacts) for additional examples and tips.

See extra documentation for the [@actions/artifact](https://github.com/actions/toolkit/blob/main/packages/artifact/docs/additional-information.md) package that is used internally regarding certain behaviors and limitations.