gh-action_cache

Adaptive cache action that automatically chooses the appropriate caching backend based on repository visibility and ownership.

• Automatically uses GitHub Actions cache for public repositories
• Uses SonarSource S3 cache for private/internal SonarSource repositories
• Seamless API compatibility with standard GitHub Actions cache
• Supports all standard cache inputs and outputs
• Automatic repository visibility detection

Requirements

• jq

Usage

- uses: SonarSource/gh-action_cache@v1
  with:
    path: |
      ~/.cache/pip
      ~/.cache/maven
    key: cache-${{ runner.os }}-${{ hashFiles('**/requirements.txt', '**/pom.xml') }}
    restore-keys: cache-${{ runner.os }}-

Inputs

Input	Description	Required	Default
path	Files, directories, and wildcard patterns to cache	Yes
key	Explicit key for restoring and saving cache	Yes
restore-keys	Ordered list of prefix-matched keys for fallback	No
fallback-branch	Optional maintenance branch for fallback restore keys (pattern: branch-*, S3 backend only). If not set, the repository default branch is used.	No
environment	Environment to use (dev or prod, S3 backend only)	No	prod
upload-chunk-size	Chunk size for large file uploads (bytes)	No
enableCrossOsArchive	Enable cross-OS cache compatibility	No	false
fail-on-cache-miss	Fail workflow if cache entry not found	No	false
lookup-only	Only check cache existence without downloading	No	false
backend	Force specific backend: github or s3	No

Outputs

Output	Description
cache-hit	Boolean indicating exact match for primary key

S3 Cache Action

A GitHub Action that provides branch-specific caching on AWS S3 with intelligent fallback to default branch cache entries.

Features

• Branch-specific caching: Cache entries are prefixed with GITHUB_HEAD_REF for granular permissions
• Intelligent fallback: Feature branches can fall back to default branch cache when no branch-specific cache exists
• S3 storage: Leverages AWS S3 for reliable, scalable cache storage
• AWS Cognito authentication: Secure authentication using GitHub Actions OIDC tokens
• Compatible with actions/cache: Drop-in replacement with same interface

How Restore Keys Work

Important: This action's restore key behavior differs from the standard GitHub cache action. To enable fallback to default branch caches, you must use the restore-keys property.

Cache Key Resolution Order

When you provide restore-keys, the action searches for cache entries in this order:

1. Primary key: ${BRANCH_NAME}/${key}
2. Branch-specific restore keys: ${BRANCH_NAME}/${restore-key} (for each restore key)
3. Default branch fallbacks:
   • refs/heads/${DEFAULT_BRANCH}/${restore-key} (for each restore key, where DEFAULT_BRANCH is dynamically obtained from the repository)

Example

- uses: SonarSource/gh-action_cache@v1
  with:
    path: ~/.npm
    key: node-${{ runner.os }}-${{ hashFiles('**/package-lock.json') }}
    restore-keys: node-${{ runner.os }}-

For a feature branch feature/new-ui, this will search for:

1. feature/new-ui/node-linux-abc123... (exact match)
2. feature/new-ui/node-linux (branch-specific partial match)
3. refs/heads/main/node-linux (default branch fallback, assuming main is the repository's default branch)

Key Differences from Standard Cache Action

• Fallback requires restore-keys: Without restore-keys, the action only looks for branch-specific cache entries
• Dynamic default branch detection: The action detects your default branch using the GitHub API and uses it for fallback
• Branch isolation: Each branch maintains its own cache namespace, preventing cross-branch cache pollution

Environment Configuration

The action supports two environments:

• dev: Development environment with development S3 bucket
• prod: Production environment with production S3 bucket (default)

Each environment has its own preconfigured S3 bucket and AWS Cognito pool for isolation and security.

Security

• Uses GitHub Actions OIDC tokens for secure authentication
• No long-lived AWS credentials required
• Branch-specific paths provide isolation between branches

Cleanup Policy

The AWS S3 bucket lifecycle rules apply to delete the old files. The content from default branches expires in 60 days and for feature branches in 30 days.