buzz/docs/guides/development.md

Development Guide

Setting up a dev environment, code style, and the PR workflow. The root CONTRIBUTING.md is the canonical contributor entry point (code of conduct, CLA); this page is the day-to-day engineering detail.

Environment setup

Prerequisites

Tool	Version	Notes
Rust	1.88+	Install via rustup
Node.js	24+	Required for desktop app commands and just ci
pnpm	10+	Required for desktop app commands and just ci
Flutter	3.41+	Required for mobile app — install via flutter.dev
Docker	24+	For Postgres, Redis, MinIO
just	latest	Task runner — cargo install just
lefthook	latest	Optional; run lefthook install for local Git hooks
sqlx migrations	workspace crate	just migrate applies embedded migrations from migrations/

This repo uses Hermit for toolchain pinning. Activate it once per shell session:

. ./bin/activate-hermit

Hermit pins Rust, just, Node, pnpm, and other tools to the versions in bin/. Each tool is downloaded on first use. You can also run just bootstrap (which just setup calls automatically) to pre-download all required tools upfront. If you don't use Hermit, ensure your toolchain meets the minimum versions in the table above.

First-Time Setup

# 1. Clone the repo
git clone https://github.com/block/buzz.git
cd buzz

# 2. Activate Hermit (optional but recommended)
. ./bin/activate-hermit

# 3. Bootstrap tools + infrastructure
just setup

# 4. Install Git hooks (optional, recommended)
just hooks

just setup runs just bootstrap first — it copies .env.example to .env if it doesn't already exist, and invokes cargo, node, and pnpm to trigger Hermit's lazy tool download (each tool is fetched once on first invocation and cached thereafter). You can also run just bootstrap independently at any time; it is safe to re-run.

just setup then starts Docker services (Postgres on :5432, Redis on :6379, Adminer on :8082, Keycloak on :8180 for local OAuth/OIDC testing, MinIO on :9000 for media storage, and Prometheus on :9090 for metrics) and runs all pending database migrations.

Running the Relay and Desktop App

just dev   # starts the relay + desktop app in one command

just dev builds all agent tools, starts the relay (ws://localhost:3000) in the background, and launches the Tauri desktop app. The relay process is automatically killed when you quit the app or press Ctrl+C.

For a split-terminal workflow (relay logs visible separately from Vite output):

just relay        # terminal 1 — relay on ws://localhost:3000
just desktop-dev  # terminal 2 — Vite dev server only (no Tauri shell)

Stopping / Resetting

just down    # Stop Docker services, keep data
just reset   # ⚠️  Wipe all data and recreate the environment

Repo layout

A Rust workspace of focused crates (see the Crate Reference), plus desktop/ (Tauri + React), web/, mobile/ (Flutter), deploy/ (Compose bundle + Helm chart), migrations/, and examples/. Task automation lives in the Justfile; Git hooks in lefthook.yml; TS lint/format in biome.json.

Code style

Formatting

We use rustfmt with default settings. Format your code before committing:

cargo fmt --all

To check without modifying:

cargo fmt --all -- --check

Linting

We use clippy with warnings-as-errors:

cargo clippy --all-targets --all-features -- -D warnings

Fix all clippy warnings before submitting a PR. If you believe a warning is a false positive, add a targeted #[allow(...)] with a comment explaining why.

No Unsafe Code

All crates enforce #![deny(unsafe_code)]. Do not add unsafe blocks. If you believe unsafe is genuinely necessary, open an issue first to discuss the approach.

Error Handling

• Use thiserror for library error types.
• Use anyhow for binary / application-level error propagation.
• Do not use unwrap() or expect() in production code paths. Use ? or explicit error handling. unwrap() is acceptable in tests.

Logging and Tracing

Use the tracing crate for all instrumentation. Prefer structured fields over string interpolation:

// Good
tracing::info!(channel_id = %id, event_kind = kind, "Event ingested");

// Avoid
tracing::info!("Event ingested: channel={id} kind={kind}");

Commit Messages

Follow Conventional Commits:

feat(mcp): add get_feed_actions tool
fix(auth): reject expired NIP-42 challenges
docs(agents): document workflow MCP tools
refactor(db): extract channel queries into channel.rs
test(workflow): add approval gate integration test

The type prefix (feat, fix, docs, refactor, test, chore) is required. The scope (in parentheses) is optional but encouraged.

Making a pull request

Before You Start

• Check open issues and PRs to avoid duplicate work.
• For significant changes, open an issue first to discuss the approach.
• For small fixes (typos, doc improvements, obvious bugs), go ahead and open a PR directly.

What a Good PR Looks Like

1. Focused — one logical change per PR. If you're fixing a bug and refactoring a module, split them into two PRs.

2. Tested — new behavior has tests. Bug fixes include a regression test. If a test is impractical, explain why in the PR description.

3. Documented — public APIs, new event kinds, new MCP tools, and new config variables are documented. Update README.md, AGENTS.md, or VISION.md as appropriate.

4. CI passing — just ci passes locally before you push.

5. Clear description — the PR description explains:

   • What problem this solves (or what feature it adds)
   • How it was implemented (key decisions, trade-offs)
   • How to test it manually (if applicable)
   • Any follow-up work deferred to a future PR

PR Checklist

- [ ] `just ci` passes (fmt + clippy + unit tests + mobile)
- [ ] Integration tests pass (`just test`)
- [ ] New public APIs / tools / endpoints are documented
- [ ] No new `unwrap()` in production code paths
- [ ] No new `unsafe` blocks

Review Process

• A maintainer will review your PR within a few business days.
• Address review comments by pushing new commits (don't force-push during review; it makes it hard to see what changed).
• Once approved, a maintainer will squash-merge your PR.

License and CLA

Buzz is licensed under the Apache License, Version 2.0. See LICENSE for the full text.

By submitting a pull request, you agree that your contribution is licensed under the Apache 2.0 license and that you have the right to submit it.

If your employer has rights to intellectual property you create, you may need their sign-off. When in doubt, check with your legal team.

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Thank you for contributing to Buzz. Every bug report, documentation fix, and code contribution makes the project better for everyone. 🐝