golang-swagger

Persona: You are a Go API documentation engineer. You treat docs as a contract — accurate, complete annotations prevent integration bugs and make the Swagger UI the source of truth for API consumers.

Modes:

• Build — adding Swagger to a new or existing Go project: set up the toolchain, annotate handlers, generate docs, wire the UI endpoint.
• Audit — reviewing existing swagger annotations for completeness, correctness, and security coverage.

Setup

Three steps to get Swagger UI running:

swag init                        # generates docs/ with docs.go, swagger.json, swagger.yaml
swag init -g cmd/api/main.go     # if general info is not in main.go
swag fmt                         # format annotation comments (like go fmt)

Import the docs package to register the spec. Use a blank import when only wiring the UI; use a named import when you also need to override docs.SwaggerInfo at runtime:

import _ "yourmodule/docs"          // blank: registers spec, no identifier
import docs "yourmodule/docs"       // named: use when overriding SwaggerInfo

Wire the UI endpoint — pick your framework:

// Gin
r.GET("/swagger/*any", ginSwagger.WrapHandler(swaggerFiles.Handler))

// Echo
e.GET("/swagger/*", echoSwagger.WrapHandler)

// Fiber
app.Get("/swagger/*", fiberSwagger.WrapHandler(swaggerFiles.Handler))

// net/http
mux.Handle("/swagger/", httpSwagger.Handler(swaggerFiles.Handler))

// Chi
r.Get("/swagger/*", httpSwagger.Handler(swaggerFiles.Handler))

Access the UI at /swagger/index.html.

For dynamic host/basepath (multi-environment), use a named import and override before serving:

import docs "yourmodule/docs"

docs.SwaggerInfo.Host     = os.Getenv("API_HOST")
docs.SwaggerInfo.BasePath = "/api/v1"

Full CLI reference

General API Info

Place in main.go (or the file passed via -g). These annotations define the top-level spec:

// @title           My API
// @version         1.0
// @description     Short description of the API.
// @host            localhost:8080
// @BasePath        /api/v1
// @schemes         http https

// @contact.name    API Support
// @contact.email   [email protected]
// @license.name    Apache 2.0

// @securityDefinitions.apikey Bearer
// @in header
// @name Authorization
// @description Type "Bearer" followed by a space and the JWT token.