BranchBase 🌿

Zero-config, Git-native local database branching for PostgreSQL, MySQL, and SQLite.
Stop dropping your local database every time you switch Git branches.

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⚡ The Problem: The "Git vs. Local Database" Friction

Every developer working with Docker, local PostgreSQL, MySQL, or SQLite has suffered this loop:

1. You work on `feature/checkout-v2`.
   └── Ran migrations: added table `stripe_orders`, added column `users.billing_tier NOT NULL`.
2. Urgent production bug alert! You run:
   └── `git checkout main`
3. You start the app or run tests on `main`.
4. 💥 CRASH:
   └── ActiveRecord::PendingMigrationError / PrismaClientKnownRequestError:
       "column users.billing_tier does not exist" or "schema mismatch detected".

How developers waste hours today:

• The Nuclear Option: docker compose down -v && docker compose up -d
  (Loses all your test seeds, logins, and mocked state. Takes minutes to re-seed).
• The Manual Rollback Dance: Trying to rollback migrations on feature/checkout-v2 before switching, only to lose experimental test data.
• The .env Nightmare: Manually maintaining DATABASE_URL_DEV, DATABASE_URL_CHECKOUT, and editing .env on every branch change.
• Cloud Branching (Neon, PlanetScale): Great developer experience, but proprietary, paid, and requires an internet connection. It doesn't work for offline development or standard local Docker setups.

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🚀 The Solution: BranchBase

BranchBase brings instant, zero-copy database branching directly to your local machine and Docker containers.

                           +---------------------------+
                           |     Developer Machine     |
                           +---------------------------+
                                         |
                                `git checkout branch-b`
                                         |
                                         v
                            [ BranchBase Git Hook ]
                                         |
                    +--------------------+--------------------+
                    |                                         |
          (Detects new branch)                      (Zero-Copy Snapshot)
                    |                                         |
                    v                                         v
+---------------------------------------+   +------------------------------------+
|       BranchBase Proxy (Port 5432)    |   |     Local Database (PostgreSQL)    |
+---------------------------------------+   +------------------------------------+
| - App connection string NEVER changes |   | - `db_project_main` (frozen)       |
| - Automatically routes queries to the |   | - `db_project_branch_b` (active)   |
|   active Git branch database!         |   |   (Created instantly via TEMPLATE) |
+---------------------------------------+   +------------------------------------+

Key Highlights

• ⚡ Instant Branching: Creates a fresh, isolated branch database in milliseconds using PostgreSQL CREATE DATABASE ... TEMPLATE or filesystem copy-on-write (reflink/APFS/Btrfs for SQLite).
• 🔌 Transparent Connection Proxy: Your app's DATABASE_URL=postgres://user:pass@localhost:5432/myapp never changes. The local proxy automatically inspects which Git branch is active in your working directory and routes traffic to that branch's database.
• 🎣 Automated Git Hook: Hooks into post-checkout and post-merge. You simply use standard git checkout or git switch.
• 🧹 Automatic Cleanup (prune): When you delete or merge a Git branch, branchbase safely tears down the associated ephemeral database.
• 📴 100% Local & Offline: No cloud telemetry, no subscription fees, no internet needed.

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📖 Command & CLI Reference

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📁 Repository Structure

branchbase/
├── cmd/
│   └── branchbase/
│       └── main.go               # CLI entry point (subcommands & signal handling)
├── internal/
│   ├── config/                   # Configuration loader (.branchbase.json / .yaml)
│   ├── driver/                   # Database engine interfaces & registry
│   │   ├── driver.go             # Core Driver interface contract
│   │   ├── postgres/             # PostgreSQL engine (TEMPLATE cloning)
│   │   └── sqlite/               # SQLite engine (CoW / Reflink snapshots)
│   ├── git/                      # Git HEAD inspector and branch sanitization
│   │   ├── resolver.go           # Non-subshell .git/HEAD resolution
│   │   └── resolver_test.go      # Table-driven unit test suite
│   ├── hook/                     # Automated Git hook manager (post-checkout/merge)
│   │   ├── hook.go               # Non-intrusive hook installer
│   │   └── hook_test.go          # Hook lifecycle test suite
│   └── proxy/                    # Transparent TCP proxy & wire routing
│       ├── pgwire/               # PostgreSQL wire-protocol StartupMessage rewriter
│       │   ├── pgwire.go         # Packet parser & database replacer
│       │   └── pgwire_test.go    # Protocol unit test suite
│       └── proxy.go              # Zero-overhead bidirectional TCP forwarder
├── .agents/                      # Custom Agent skills & development workflows
├── .github/                      # CI workflows, issue templates, dependabot
├── ARCHITECTURE.md               # Detailed system design & sequence diagrams
├── CONTRIBUTING.md               # Contributor guide & driver creation tutorial
├── SETUP.md                      # Local developer environment setup guide
├── SECURITY.md                   # Security policy & private vulnerability reporting
├── CODE_OF_CONDUCT.md            # Contributor Covenant v2.1
├── CHANGELOG.md                  # Keep a Changelog version history
├── branchbase.example.yaml       # Annotated configuration specification
└── go.mod                        # Go 1.22+ module definition

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⚙️ How It Works (Step-by-Step)

1. Detection: When you run git checkout <branch>, BranchBase's hook (.git/hooks/post-checkout) detects the branch transition in under 5ms by reading .git/HEAD.
2. Identifier Sanitization: Special characters like / or - in branch names (e.g. feature/stripe-v2) are converted into safe database identifiers (feature_stripe_v2).
3. Copy-on-Write Snapshot:
   • PostgreSQL: Disconnects lingering connections to the template and executes CREATE DATABASE <target> TEMPLATE <source>; (instant CoW clone).
   • SQLite: Issues PRAGMA wal_checkpoint(TRUNCATE); and performs a filesystem reflink/clone (clonefile() or FICLONE).
4. Transparent Routing: When your backend app queries localhost:5432, the BranchBase proxy intercepts the connection, resolves the active branch database, and forwards traffic seamlessly.
5. Lifecycle Pruning: Once a PR is merged into main, running branchbase prune removes the ephemeral database, freeing disk space.

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🧩 Extension Model: Adding a New Database Driver

External engines are pluggable by design. Adding a new database driver requires just 1 package and 1 interface implementation:

// internal/driver/driver.go
type Driver interface {
    Name() string
    Ping(ctx context.Context) error
    BranchExists(ctx context.Context, branchName string) (bool, error)
    CreateBranch(ctx context.Context, sourceBranch, targetBranch string) error
    DeleteBranch(ctx context.Context, branchName string) error
    ListBranches(ctx context.Context) ([]BranchInfo, error)
}

1. Create internal/driver/<engine>/<engine>.go.
2. Implement the Driver interface.
3. Register your factory via driver.Register("<engine>", factory) in init().
4. See our dedicated Driver Development Skill for full instructions.

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🛠️ Quickstart

1. Initialize in your Repository

cd my-awesome-project
branchbase init

2. Start the Transparent Proxy

branchbase proxy

3. Work with Git as you always do!

# Branch to a new feature:
git checkout -b feature/stripe-billing

# Run migrations freely:
npx prisma migrate dev  # or rails db:migrate / alembic upgrade head

# Switch back to main whenever you want:
git checkout main
# Proxy immediately routes traffic back to your main database! No migration errors!

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🤝 Contributing & Community

Thinking about contributing? We'd love to have you!

• New Contributors: Check our good first issue label for onboarding tasks.
• Contributor Guide: Read CONTRIBUTING.md for coding standards, Conventional Commits, and PR rules.
• Environment Setup: See SETUP.md for local Go and Docker development steps.
• Code of Conduct: All interactions are governed by our Code of Conduct.

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🛡️ Security

To report a vulnerability privately, please see SECURITY.md or use GitHub Private Vulnerability Reporting.

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💖 Support & Sponsorship

If you find BranchBase useful in your daily development or it saved you hours of debugging migration mismatches, consider supporting ongoing development:

• 💖 Sponsor on GitHub Sponsors
• ☕ Buy me a coffee on Ko-Fi

Your sponsorship helps fund test infrastructure, multi-database driver maintenance, and cross-platform packaging!

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📄 License

Licensed under the MIT License.