Rego

A lightweight Redis-compatible server written in Go. Rego speaks the RESP protocol so it can be driven by standard Redis clients while providing core Redis data structures, replication, and persistence features.

Features

• RESP protocol compatibility for use with existing Redis tooling
• String storage with NX/XX and PX/EX options plus atomic INCR
• Durable state via RDB parsing on startup with optional replica mode
• Transaction support (MULTI/EXEC/DISCARD) and synchronous replication via WAIT
• Stream primitives (XADD, XRANGE, XREAD) for append-only data
• List data type with blocking pops (BLPOP) for queue-style workloads
• Pub/Sub channels with SUBSCRIBE, UNSUBSCRIBE, and PUBLISH
• Sorted sets backing both ZSET commands and geospatial queries (GEO*)

Getting Started

Prerequisites

• Go 1.21 or higher

Running the Server

# Run the server with default settings
./run.sh

# Run the server with custom settings
./run.sh --port 6380 --dir /path/to/data --dbfilename custom.rdb

Setting up Replication

To create a replica instance:

# Start the master on the default port (6379)
./run.sh

# Start a replica on port 6380
./run.sh --port 6380 --replicaof "localhost 6379"

Project Structure

• app/ – Server source code
  • main.go – Process entrypoint, connection handling, CLI flags
  • handler.go – RESP command registry and command implementations
  • resp.go – RESP encoder/decoder
  • key-value-store.go – In-memory store with TTL management
  • config.go – Runtime configuration and replication offsets
  • replica.go – Master/replica synchronization logic
  • rdb_parser.go – RDB file parser and loader
  • stream.go, stream_manager.go – Stream data structure and range/read helpers
  • list.go, list_manager.go – List operations plus blocking pop coordination
  • pubsub_manager.go – Channel subscription tracking and message fan-out
  • sorted_set.go – Sorted set storage used by ZSET and GEO commands
• run.sh – Convenience script to build and run the server
• create_rdb.sh, dump.rdb, empty.rdb – Test fixtures for RDB parsing

Supported Commands

• Basic: PING, ECHO
• Strings: SET, GET, INCR, TYPE
• Keys: KEYS
• Configuration & replication: CONFIG GET, INFO REPLICATION, REPLCONF, PSYNC, WAIT
• Transactions: MULTI, EXEC, DISCARD
• Streams: XADD, XRANGE, XREAD
• Lists: LPUSH, RPUSH, LRANGE, LLEN, LPOP, BLPOP
• Pub/Sub: SUBSCRIBE, UNSUBSCRIBE, PUBLISH
• Sorted sets: ZADD, ZRANGE, ZRANK, ZCARD, ZSCORE, ZREM
• Geospatial: GEOADD, GEOPOS, GEODIST, GEOSEARCH

The server is intentionally focused on the subset of Redis features above, making it a practical playground for understanding how Redis works under the hood.