cache/README.md

cache

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

Documentation

See "Caching dependencies to speed up workflows".

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 - A directory to store and save the cache
• 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

Example workflow

name: Caching Primes

on: push

jobs:
  build:
    runs-on: ubuntu-latest
    
    steps:
    - uses: actions/checkout@v1

    - name: Cache Primes
      id: cache-primes
      uses: actions/cache@v1
      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 it's own way of caching.

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

• C# - Nuget
• Elixir - Mix
• Go - Modules
• Java - Gradle
• Java - Maven
• Node - npm
• Node - Yarn
• PHP - Composer
• Python - pip
• Ruby - Gem
• Rust - Cargo
• Swift, Objective-C - Carthage
• Swift, Objective-C - CocoaPods

Cache Limits

Individual caches are limited to 400MB and a repository can have up to 2GB of caches. Once the 2GB 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@v1

  - uses: actions/cache@v1
    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