GCS filesystem

[FedeBev]

Hi,

it would be great to have GCS filesystem as well.

I can work on the implementation if needed

Thanks

[vsychov]

It would be great to get GCS support in this tool, especially considering that it is already supported by the afero: https://github.com/spf13/afero?tab=readme-ov-file#gcsfs

[fclairamb]

@claude can you try to implement this and create the associated pull request. You can probably take inspiration from the AWS S3 implementation.

[claude[bot]]

Claude finished @fclairamb's task —— View job • claude/issue-1421-20250829-2247 • Create PR ➔

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Implementing GCS filesystem support ✅

I'll implement GCS filesystem support taking inspiration from the existing S3 implementation as suggested.

Todo List:

• [x] Read repository structure and CLAUDE.md guidelines
• [x] Analyze existing S3 filesystem implementation
• [x] Research GCS support in afero library
• [x] Implement GCS filesystem following S3 patterns
• [x] Add GCS configuration support
• [x] Update relevant documentation/examples
• [x] Run tests and linting
• [x] Commit and push changes
• [x] Provide PR creation link

Implementation Summary:

Successfully implemented complete GCS filesystem support with:

Core Features:

• Full afero.Fs interface implementation using cloud.google.com/go/storage
• Support for all standard file operations (read, write, delete, stat, etc.)
• Directory operations (emulated since GCS is object-based)
• Proper error handling and edge case management

Authentication Options:

• Service account key file authentication (key_file parameter)
• Default credential chain (environment variables, gcloud CLI, metadata service)
• Optional project ID specification

Configuration Parameters:

• bucket (required): GCS bucket name
• project_id (optional): Google Cloud Project ID
• key_file (optional): Path to service account JSON key

Files Added/Modified:

• fs/gcs/gcs.go: Complete GCS filesystem implementation
• fs/gcs/README.md: Comprehensive documentation with examples
• fs/fs.go: Added GCS to filesystem dispatcher
• go.mod: Added required GCS dependencies

Create Pull Request:

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Branch: claude/issue-1421-20250829-2247