ServGate

docker run -p 8080:8080 ghcr.io/vyuvaraj/servgate:latest

ServGate is a high-performance, programmable API Gateway and reverse proxy tailored for the Serv ecosystem. Its primary differentiating feature is WASM-Powered Middleware: the ability to execute sandboxed WebAssembly (WASI) modules inline on incoming request or response cycles to inspect, validate, or mutate payloads before forwarding.

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Key Features

• Reverse Proxy: Dynamic path-based routing (e.g. /api/v1/orders/* -> http://127.0.0.1:8081) with automatic URL prefix stripping.
• WASM Inline Middleware: Execute guest WASI filters to validate headers, manipulate query params, or enrich body payloads.
• Distributed Observability: Seamless trace propagation using OpenTelemetry standard headers (traceparent) and JSON-based OTLP span exports.
• Authentication Security: Build-in OAuth2 Bearer token checks for all routed backend targets.

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Quick Start

1. Build and Run

Ensure you have Go installed, then compile and run:

go build -o servgate.exe main.go
./servgate.exe

• The API Gateway reverse proxy listens on :8080 (configured via config.json).
• Dynamic middleware registration is managed via /api/admin/middleware/{name}.

2. Configuration (config.json)

Manage routes declaratively:

{
  "addr": ":8080",
  "auth_token": "gateway-secret-token",
  "routes": [
    {
      "prefix": "/api/v1/orders",
      "target": "http://127.0.0.1:8081",
      "middleware": "validator"
    }
  ]
}

3. Dynamic Middleware Registration

Register a compiled .wasm middleware:

curl -X POST http://localhost:8080/api/admin/middleware/validator \
  -H "Authorization: Bearer gateway-secret-token" \
  --data-binary @my_validator.wasm

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Verification

Run integration tests:

go test ./... -v

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Standalone Gateway Setup (Express / Flask / Spring Boot)

ServGate can act as a high-performance standalone API Gateway in front of non-ecosystem applications built with frameworks like Node.js (Express), Python (Flask), or Java (Spring Boot) without requiring any WebAssembly filters:

1. Express Backend Setup (Node.js)

To forward client requests dynamically from ServGate to an Express app listening on :3000:

• Configure a path-based routing rule in config.json:

  {
    "prefix": "/api/users",
    "target": "http://localhost:3000"
  }

• Requests to http://localhost:8080/api/users/profile will be automatically stripped and routed to http://localhost:3000/profile.

2. Flask Backend Setup (Python)

For Flask APIs running on port :5000:

• Add the routing target rule to your config.json list:

  {
    "prefix": "/api/predict",
    "target": "http://localhost:5000"
  }

• ServGate handles HTTP headers forwarding, logging, and connection pooling out-of-the-box.

3. Spring Boot Backend Setup (Java)

For Spring Boot controllers running on port :8080 (or custom port :8081):

• Configure the target path mappings:

  {
    "prefix": "/api/v1/billing",
    "target": "http://localhost:8081"
  }

Complete Standalone config.json Example

Create a config.json file combining your multi-backend routing policies:

{
  "addr": ":8080",
  "auth_token": "gateway-secret-token",
  "routes": [
    {
      "prefix": "/api/users",
      "target": "http://localhost:3000"
    },
    {
      "prefix": "/api/predict",
      "target": "http://localhost:5000"
    },
    {
      "prefix": "/api/v1/billing",
      "target": "http://localhost:8081"
    }
  ]
}

Launch Standalone Gateway

Start the gateway pointing directly to your custom config file:

./servgate.exe --standalone --config config.json

The gateway is now running at http://localhost:8080, proxying requests dynamically based on prefixes!