- name: Cache multiple paths
  uses: actions/cache@v2
  with:
    path: |
      ~/cache
      !~/cache/exclude      
    key: ${{ runner.os }}-${{ hashFiles('**/lockfiles') }}

Increased performance and improved cache sizes using zstd compression for Linux and macOS runners
Allowed caching for all events with a ref. See events that trigger workflow for info on which events do not have a GITHUB_REF
Released the @actions/cache npm package to allow other actions to utilize caching
Added a best-effort cleanup step to delete the archive after extraction to reduce storage space

Refer here for previous versions

Usage

Pre-requisites

Create a workflow .yml file in your repositories .github/workflows directory. An example workflow is available below. For more information, reference the GitHub Help Documentation for Creating a workflow file.

If you are using this inside a container, a POSIX-compliant tar needs to be included and accessible in the execution path.

Inputs

path - A list of files, directories, and wildcard patterns to cache and restore. See @actions/glob for supported patterns.
key - An explicit key for restoring and saving the cache
restore-keys - An ordered list of keys to use for restoring the cache if no cache hit occurred for key

Outputs

cache-hit - A boolean value to indicate an exact match was found for the key

See Skipping steps based on cache-hit for info on using this output

Cache scopes

The cache is scoped to the key and branch. The default branch cache is available to other branches.

See Matching a cache key for more info.

Example workflow

name: Caching Primes

on: push

jobs:
  build:
    runs-on: ubuntu-latest

    steps:
    - uses: actions/checkout@v2

    - name: Cache Primes
      id: cache-primes
      uses: actions/cache@v2
      with:
        path: prime-numbers
        key: ${{ runner.os }}-primes

    - name: Generate Prime Numbers
      if: steps.cache-primes.outputs.cache-hit != 'true'
      run: /generate-primes.sh -d prime-numbers

    - name: Use Prime Numbers
      run: /primes.sh -d prime-numbers

Implementation Examples

Every programming language and framework has its own way of caching.

See Examples for a list of actions/cache implementations for use with:

Creating a cache key

A cache key can include any of the contexts, functions, literals, and operators supported by GitHub Actions.

For example, using the hashFiles function allows you to create a new cache when dependencies change.

  - uses: actions/cache@v2
    with:
      path: |
        path/to/dependencies
        some/other/dependencies        
      key: ${{ runner.os }}-${{ hashFiles('**/lockfiles') }}

Additionally, you can use arbitrary command output in a cache key, such as a date or software version:

  # http://man7.org/linux/man-pages/man1/date.1.html
  - name: Get Date
    id: get-date
    run: |
      echo "::set-output name=date::$(/bin/date -u "+%Y%m%d")"      
    shell: bash

  - uses: actions/cache@v2
    with:
      path: path/to/dependencies
      key: ${{ runner.os }}-${{ steps.get-date.outputs.date }}-${{ hashFiles('**/lockfiles') }}

See Using contexts to create cache keys

Cache Limits

A repository can have up to 10GB of caches. Once the 10GB limit is reached, older caches will be evicted based on when the cache was last accessed. Caches that are not accessed within the last week will also be evicted.

Skipping steps based on cache-hit

Using the cache-hit output, subsequent steps (such as install or build) can be skipped when a cache hit occurs on the key.

Example:

steps:
  - uses: actions/checkout@v2

  - uses: actions/cache@v2
    id: cache
    with:
      path: path/to/dependencies
      key: ${{ runner.os }}-${{ hashFiles('**/lockfiles') }}

  - name: Install Dependencies
    if: steps.cache.outputs.cache-hit != 'true'
    run: /install.sh

Note: The id defined in actions/cache must match the id in the if statement (i.e. steps.[ID].outputs.cache-hit)

Known limitation

action/cache is currently not supported on GitHub Enterprise Server. https://github.com/github/roadmap/issues/273 is tracking this.

Since GitHub Enterprise Server uses self-hosted runners, dependencies are typically cached on the runner by whatever dependency management tool is being used (npm, maven, etc.). This eliminates the need for explicit caching in some scenarios.

Contributing

We would love for you to contribute to actions/cache, pull requests are welcome! Please see the CONTRIBUTING.md for more information.

License

The scripts and documentation in this project are released under the MIT License