Copybara Documentation

Unofficial Documentation

This is community-maintained documentation, not official Google documentation. For official resources, see: - Official Repository - Official Reference - Official Examples

What is Copybara?

Copybara is Google’s tool for transforming and moving code between repositories. It enables workflows like:

• Open sourcing internal code to public repositories
• Importing contributions from external repos back to internal
• Mirroring repositories with transformations
• Syncing subsets of monorepos to standalone repositories

Workflows

Learn about SQUASH, ITERATIVE, and CHANGE_REQUEST modes for different sync scenarios.

Transformations

Move files, replace text, filter content, and verify no secrets are leaked.

GitHub Integration

Create pull requests automatically instead of direct pushes.

CI/CD

Run Copybara in GitHub Actions with automated triggers.

Quick Example

copy.bara.sky

core.workflow(
    name = "export-to-github",
    origin = git.origin(
        url = "https://internal.git/repo",
        ref = "main",
    ),
    destination = git.github_pr_destination(
        url = "https://github.com/org/public-repo",
        destination_ref = "main",
    ),
    origin_files = glob(["src/**"], exclude = ["**/internal/**"]),
    transformations = [
        core.move("src/", ""),
        core.replace("internal.corp", "example.com"),
    ],
    mode = "SQUASH",
)

Why Copybara?

Feature	Benefit
Declarative config	Define what you want, not how to do it
Bidirectional	Export and import between any repositories
Transformations	Modify paths, content, and metadata during sync
State tracking	Automatically tracks what’s been synced
PR-based	Create PRs instead of direct pushes

Acknowledgements

Copybara is developed by Google and licensed under Apache License 2.0.