golang-api-server

name	golang-api-server
description	Standards for building HTTP services, REST APIs, and middleware in Golang. Use when building Go HTTP servers, REST APIs, or custom middleware. (triggers: cmd/server/*.go, internal/adapter/handler/**, http server, rest api, gin, echo, middleware)

Golang API Server Standards

Priority: P0 (CRITICAL)

Router Selection

• Standard Lib (net/http): Use for simple services or when zero deps is required. Use http.ServeMux (Go 1.22+ has decent routing).
• Echo (labstack/echo): Recommended for production REST APIs. Excellent middleware support, binding, and error handling.
• Gin (gin-gonic/gin): High performance alternative.

Guidelines

• Graceful Shutdown: MUST implement graceful shutdown to handle in-flight requests on termination (SIGINT/SIGTERM).
• DTOs: Separate Domain structs from API Request/Response structs. Map between them.
• Middleware: Use middleware for cross-cutting concerns (Logging, Recovery, CORS, Auth, Tracing).
• Health Checks: Always include /health and /ready endpoints.
• Content-Type: Enforce application/json for REST APIs.

Middleware Pattern

• Standard: func(next http.Handler) http.Handler
• Echo implementation: func(next echo.HandlerFunc) echo.HandlerFunc

Anti-Patterns

• No business logic in handlers: Parse request → call service → format response only.
• No global router vars: Pass router instance via constructor or DI.
• No missing graceful shutdown: Always handle SIGTERM to drain in-flight requests.

References

• Middleware Patterns
• Graceful Shutdown