cache

This action allows caching dependencies and build outputs to improve workflow execution time.

Documentation

See "Caching dependencies to speed up workflows".

What's New in V2

• Added support for caching multiple paths,

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

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

glob patterns,

- name: Cache using glob patterns
  uses: actions/cache@v2
  with:
    path: |
      **/*.ts
      **/node_modules      
    key: ${{ runner.os }}-${{ hashFiles('**/lockfiles') }}

and single file caches.

- name: Cache single file
  uses: actions/cache@v2
  with:
    path: cache.tar
    key: ${{ runner.os }}

• Increased perfomance and improved cache sizes using zstd compression

Note this feature is off for Windows runner that are using bsdtar (e.g., windows-latest hosted runner) due to a bug in ziping large random files with bsdtar

• 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

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.

Inputs

• path - Directories to store and save the cache. Supports pattern matching, multipath and single file cache

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:

• C# - Nuget
• D - DUB
• Elixir - Mix
• Go - Modules
• Haskell - Cabal
• Java - Gradle
• Java - Maven
• Node - npm
• Node - Lerna
• Node - Yarn
• OCaml/Reason - esy
• PHP - Composer
• Python - pip
• R - renv
• Ruby - Bundler
• Rust - Cargo
• Scala - SBT
• Swift, Objective-C - Carthage
• Swift, Objective-C - CocoaPods
• Swift - Swift Package Manager

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 5GB of caches. Once the 5GB 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)

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