【Go API 开发实战 5】基础1：启动一个最简单的 RESTful API 服务器

如无特别说明，本教程的操作和编译目录均是 API 源码的根目录，并且本 API 服务器名字（也是二进制命令的名字）教程中统一叫作 apiserver。

package mainimport (    "log"
    "net/http"

    "apiserver/router"

    "github.com/gin-gonic/gin")func main() {    // Create the Gin engine.
    g := gin.New()    // gin middlewares
    middlewares := []gin.HandlerFunc{}    // Routes.
    router.Load(        // Cores.
        g,        // Middlewares.
        middlewares...,
    )

    log.Printf("Start to listening the incoming requests on http address: %s", ":8080")
    log.Printf(http.ListenAndServe(":8080", g).Error())
}

    "apiserver/handler/sd"

    ....    // The health check handlers
    svcd := g.Group("/sd")
    {   
        svcd.GET("/health", sd.HealthCheck)
        svcd.GET("/disk", sd.DiskCheck)
        svcd.GET("/cpu", sd.CPUCheck)
        svcd.GET("/ram", sd.RAMCheck)
    }

    g.Use(gin.Recovery())
    g.Use(middleware.NoCache)
    g.Use(middleware.Options)
    g.Use(middleware.Secure)

func main() {
    ....    // Ping the server to make sure the router is working.
    go func() {        if err := pingServer(); err != nil {
            log.Fatal("The router has no response, or it might took too long to start up.", err)
        }   
        log.Print("The router has been deployed successfully.")
    }()
    ....
}// pingServer pings the http server to make sure the router is working.func pingServer() error {    for i := 0; i < 10; i++ {        // Ping the server by sending a GET request to `/health`.
        resp, err := http.Get("http://127.0.0.1:8080" + "/sd/health")        if err == nil && resp.StatusCode == 200 {            return nil 
        }   

        // Sleep for a second to continue the next ping.
        log.Print("Waiting for the router, retry in 1 second.")
        time.Sleep(time.Second)
    }  
    return errors.New("Cannot connect to the router.")
}

$ cd $GOPATH/src
$ git clone https://github.com/lexkong/vendor

$ cd $GOPATH/src/apiserver
$ gofmt -w .   
$ go tool vet .
$ go build -v .

-X/--request [GET|POST|PUT|DELETE|…]  指定请求的 HTTP 方法
-H/--header                           指定请求的 HTTP Header
-d/--data                             指定请求的 HTTP 消息体（Body）
-v/--verbose                          输出详细的返回信息
-u/--user                             指定账号、密码
-b/--cookie                           读取 cookie

$ curl -v -XPOST -H "Content-Type: application/json" http://127.0.0.1:8080/user -d'{"username":"admin","password":"admin1234"}'

$ ./apiserver
[GIN-debug] [WARNING] Running in "debug" mode. Switch to "release" mode in production.
 - using env:   export GIN_MODE=release
 - using code:  gin.SetMode(gin.ReleaseMode)

[GIN-debug] GET    /sd/health                --> apiserver/handler/sd.HealthCheck (5 handlers)
[GIN-debug] GET    /sd/disk                  --> apiserver/handler/sd.DiskCheck (5 handlers)
[GIN-debug] GET    /sd/cpu                   --> apiserver/handler/sd.CPUCheck (5 handlers)
[GIN-debug] GET    /sd/ram                   --> apiserver/handler/sd.RAMCheck (5 handlers)
Start to listening the incoming requests on http address: :8080
The router has been deployed successfully.

$ curl -XGET http://127.0.0.1:8080/sd/health
OK

$ curl -XGET http://127.0.0.1:8080/sd/disk
OK - Free space: 16321MB (15GB) / 51200MB (50GB) | Used: 31%

$ curl -XGET http://127.0.0.1:8080/sd/cpu
CRITICAL - Load average: 2.39, 2.13, 1.97 | Cores: 2$ curl -XGET http://127.0.0.1:8080/sd/ram
OK - Free space: 455MB (0GB) / 8192MB (8GB) | Used: 5%