rebab

A tiny, rule-based reverse proxy written in Rust. It listens on a single frontend socket address and forwards each incoming request to a backend determined by the first matching rule. Perfect for local dev and simple edge routing without bringing in a full Nginx stack.

Features

• 🧭 First-match routing by path prefix
• 🧪 Minimal config (config.json)
• 🔁 Forwards all methods/bodies; strips hop-by-hop headers
• 🐳 Works nicely in docker-compose (service name DNS like api:8080)

Installation

You can install rebab directly from crates.io using Cargo:

cargo install rebab

This will place the rebab binary into your Cargo bin directory (usually ~/.cargo/bin).

If you are developing locally instead, you can also build and run it manually:

cargo build --release
cargo run -- --input config.json

Usage

rebab --input config.json

config.json

{
	"frontend": "0.0.0.0:8080",
	"comment": "Routing follows the first matching rule.",
	"rules":[
		{
			"frontend_prefix": "/api/",
			"backend_port": 8000,
			"comment": "Requests whose path starts with 'api' are routed to localhost:8000."
		},
		{
			"frontend_prefix": "/example/",
			"backend_host": "example.com",
			"comment": "Requests whose path starts with 'example' are routed to example.com (the port inherits the frontend port 8080)."
		},
		{
			"backend_port": 3000,
			"comment": "All other requests are routed to localhost:3000."
		}
	]
}

The complete JSON Schema for config.json is available at src/schema.json.

Config schema (informal)

• frontend (string): Socket address to listen on (e.g., 0.0.0.0:8080)

• rules[]:

  • frontend_prefix (string|null): Path prefix to match. If omitted, matches everything.
  • backend_host (string|null): Backend host or IP. Defaults to localhost if omitted.
  • backend_port (integer|null): Backend port. Defaults to the frontend port if omitted.

Rules are evaluated in order; the first match wins.

Examples

• /api/users → localhost:8000/api/users
• /example/docs → example.com:8080/example/docs
• /anything-else → localhost:3000/anything-else

Notes

• Designed for HTTP/1.1; hop-by-hop headers (Connection, TE, etc.) are removed on proxying.
• In docker-compose, backend_host can be a service name (e.g., "api").