Architecture

Workspace Layout

Rust Packages

• packages/chabi-core Contains RESP types, command implementations, storage types, and shared primitives.

• packages/chabi-server The main runtime. It wires the command registry, Redis TCP server, HTTP server, metrics, and snapshot persistence.

• packages/chabi-redis-handler Experimental reusable RESP server components.

• packages/chabi-http-handler Experimental reusable HTTP handler components.

Rust Apps

• apps/chabi-tester End-to-end integration tests across Redis and HTTP.

• apps/membench Go benchmark harness used for local and CI performance measurements.

Docs App

• apps/docs Static Next.js + Fumadocs site for Chabi documentation.

Runtime Shape

At startup, packages/chabi-server/src/main.rs:

1. Parses CLI flags.
2. Resolves environment-driven ports and snapshot settings.
3. Creates a snapshot directory if one was not explicitly provided.
4. Starts the Redis TCP server and HTTP server concurrently.

Redis Server Design

The Redis server:

• Keeps 16 logical databases.
• Builds one command registry per database.
• Tracks connection counts and total command counters for metrics.
• Handles some commands through special dispatch logic rather than the per-db registry.

That special path is where SELECT, FLUSHALL, transaction commands, pattern subscriptions, and SAVE live.

HTTP Server Design

The HTTP server is intentionally direct and minimal:

• GET / health response
• GET /metrics Prometheus text
• GET /snapshot JSON representation of the current snapshot state

It is not currently a second client API for reading and writing arbitrary keys.

Persistence Design

Chabi builds point-in-time snapshots from the in-memory stores, serializes them into redb, and restores them on boot.

Snapshot coverage includes:

• strings
• lists
• sets
• hashes
• sorted sets
• HyperLogLog
• expirations

The file path is always:

<snapshot_dir>/chabi.kdb