proton-backup/CLAUDE.md

proton-backup

A Go CLI tool for backing up local directories to Proton Drive with rate limiting, retry logic, and resume support.

Build

go build

Install

cp proton-backup ~/bin/

Run

proton-backup -source /path/to/backup -remote /proton/drive/path

Project Structure

• main.go - Single-file implementation containing:
  • CLI argument parsing
  • Proton Drive authentication (username/password or env vars)
  • Credential caching (~/.config/proton-backup/credentials.json)
  • Directory walking and file upload
  • SQLite state tracking for resume (~/.config/proton-backup/state.db)
  • Rate limiting and exponential backoff on errors

Dependencies

• github.com/henrybear327/Proton-API-Bridge - Proton Drive API with client-side encryption
• github.com/mattn/go-sqlite3 - State tracking
• golang.org/x/term - Secure password input

Key Configuration

The AppVersion header is required by Proton's API. Current value: web-drive@5.2.0 (from Proton WebClients repo). If authentication fails with "Invalid app version", check https://github.com/ProtonMail/WebClients/blob/main/applications/drive/package.json for the current version.

Authentication

First run prompts for credentials interactively. Alternatively, set environment variables:

• PROTON_USERNAME
• PROTON_PASSWORD

Systemd Integration

Timer and service files are in ~/.config/systemd/user/:

• backup-immich-proton.service
• backup-immich-proton.timer

Testing

No automated tests yet. Manual testing:

# Dry run (still requires auth)
proton-backup -source /tank/immich/library -remote /backups/immich -dry-run

# Verbose output
proton-backup -source /tank/immich/library -remote /backups/immich -verbose