merp/server.go

package merp

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import "encoding/json"
import "fmt"
import "net/http"
import "os"
import "time"

//import "github.com/rs/zerolog/log"
import "github.com/didip/tollbooth"
import "github.com/didip/tollbooth_gin"
import "github.com/gin-gonic/gin"
import "github.com/dn365/gin-zerolog"
import "github.com/thoas/stats"

// ServeForever causes merp to serve http forever
func ServeForever() {
	s := getServer()
	s.ListenAndServe()
}

func getHealthCheckHandler() http.HandlerFunc {
	return func(w http.ResponseWriter, r *http.Request) {
		result := gin.H{
			"status": "ok",
			"now":    time.Now().UTC().Format(time.RFC3339),
		}
		json, err := json.Marshal(result)
		if err != nil {
			http.Error(w, err.Error(), http.StatusInternalServerError)
			return
		}

		w.Header().Set("Content-Type", "application/json")
		w.Write(json)
	}
}

func getStatsHandler(middleware *stats.Stats) http.HandlerFunc {
	return func(w http.ResponseWriter, r *http.Request) {
		w.Header().Set("Content-Type", "application/json")
		stats := middleware.Data()
		b, _ := json.Marshal(stats)
		w.Write(b)
	}
}

func getRouter() *gin.Engine {

	if os.Getenv("DEBUG") == "" {
		gin.SetMode(gin.ReleaseMode)
	}

	limiter := tollbooth.NewLimiter(5, nil)

	statsMiddleware := stats.New()

	// empty router
	r := gin.New()

	// wrap panics:
	r.Use(gin.Recovery())

	// attach logger middleware
	r.Use(ginzerolog.Logger("gin"))

	r.Use(func(c *gin.Context) {
		beginning, recorder := statsMiddleware.Begin(c.Writer)
		c.Next()
		statsMiddleware.End(beginning, stats.WithRecorder(recorder))
	})

	r.GET("/.well-known/healthcheck.json", gin.WrapF(getHealthCheckHandler()))
	r.GET("/admin/healthcheck.json", gin.WrapF(getHealthCheckHandler()))
	r.GET("/admin/stats.json", gin.WrapF(getStatsHandler(statsMiddleware)))
	r.GET("/admin/other.json", gin.WrapF(getStatsHandler(statsMiddleware)))

	// call it, it returns the appropriate handler function
	// so we can execute some code at startup time
	// and not just request time
	r.GET("/merp/for/:thing", tollbooth_gin.LimitHandler(limiter), handleNewMerp())
	r.GET("/get/latest/merp/for/:thing", tollbooth_gin.LimitHandler(limiter), getLatestMerp())
	r.GET("/get/latest/merps", tollbooth_gin.LimitHandler(limiter), getLatestMerps())
	r.GET("/get/merps/for/:thing", tollbooth_gin.LimitHandler(limiter), getLatestMerps())

	return r
}

func getServer() *http.Server {
	r := getRouter()

	port := "8080"
	if os.Getenv("PORT") != "" {
		port = os.Getenv("PORT")
	}

	s := &http.Server{
		Addr:           fmt.Sprintf(":%s", port),
		Handler:        r,
		ReadTimeout:    10 * time.Second,
		WriteTimeout:   10 * time.Second,
		MaxHeaderBytes: 1 << 20,
	}
	return s
}