This implements authentication for container registries, porting
functionality from go-containerregistry's authn package to Rust.
Key features:
- AuthConfig struct for various auth types (basic, bearer, anonymous)
- Authenticator trait for pluggable auth providers
- DefaultKeychain that reads Docker config files from standard locations
- Support for credential helpers (docker-credential-*)
- Integration with oci-distribution for registry operations
The implementation checks for credentials in this order:
1. DOCKER_CONFIG environment variable
2. REGISTRY_AUTH_FILE environment variable
3. XDG_RUNTIME_DIR/containers/auth.json
4. HOME/.docker/config.json
Credential helpers are supported if configured in the Docker config.
This enables krust to:
- Pull private base images
- Push to authenticated registries
- Support various auth methods (basic, token, oauth2)
Closes#2🤖 Generated with [Claude Code](https://claude.ai/code)
Co-Authored-By: Claude <noreply@anthropic.com>
