api-gateway-routing

Gateway Routing with Rate Limiting and Version-Aware Transforms

Your API gateway needs to authenticate tokens, enforce rate limits per client, route requests to the right service, and format responses differently for different client versions. This workflow chains auth, rate checking (45/100 used, 55 remaining), routing to order-service, and version-aware response transformation.

Workflow

path, method, headers, body
           |
           v
+--------------------+     +------------------+     +--------------------+     +---------------------------+
| gw_authenticate    | --> | gw_rate_check    | --> | gw_route_request   | --> | gw_transform_response     |
+--------------------+     +------------------+     +--------------------+     +---------------------------+
  clientId: client-42       45/100 used              POST /orders ->           formatted for
  clientVersion: v2         55 remaining              order-service             clientVersion v2
  requestId: REQ-fixed-001  allowed: true             orderId: ORD-123

Workers

AuthenticateWorker -- Validates the token for the requested path. Returns clientId: "client-42", clientVersion: "v2", requestId: "REQ-fixed-001".

RateCheckWorker -- Checks the client's rate limit: 45 of 100 requests used, remaining: 55, allowed: true.

RouteRequestWorker -- Routes method + path to order-service. Returns statusCode: 200 with response: {orderId: "ORD-123", status: "confirmed"}.

TransformResponseWorker -- Formats the response for the clientVersion.

Tests

31 unit tests cover authentication, rate limiting, routing, and response transformation.

Running

See ../../RUNNING.md for setup and execution instructions.