merp/server.go

package merp

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

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"

import "github.com/astaxie/beego/orm"
import _ "github.com/lib/pq" //revive:disable-line

type MerpServer struct {
	db         orm.Ormer
	debug      bool
	gin        *gin.Engine
	port       uint
	server     *http.Server
	stats      *stats.Stats
	thingRegex *regexp.Regexp
}

func NewMerpServer() *MerpServer {
	ms := new(MerpServer)
	ms.init()
	return ms
}

func (ms *MerpServer) init() {

	ms.thingRegex = regexp.MustCompile(`^[a-zA-Z0-9\_\-]+$`)

	if os.Getenv("DEBUG") != "" {
		ms.debug = true
	}

	ms.port = 8080
	var s uint64
	var err error
	if os.Getenv("PORT") != "" {
		if s, err = strconv.ParseUint(os.Getenv("PORT"), 10, 64); err == nil {
		} else {
			panic("invalid PORT in environment")
		}
		ms.port = uint(s)
	}
	ms.connectDB()
	ms.setupRoutes()

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

func (ms *MerpServer) connectDB() {
	ms.db = GetDB()
}

// ServeForever causes merp to serve http forever
func (ms *MerpServer) ServeForever() {
	ms.server.ListenAndServe()
}

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

func (ms *MerpServer) setupRoutes() {
	if !ms.debug {
		gin.SetMode(gin.ReleaseMode)
	}

	limiter := tollbooth.NewLimiter(5, nil)

	ms.stats = 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 := ms.stats.Begin(c.Writer)
		c.Next()
		ms.stats.End(beginning, stats.WithRecorder(recorder))
	})

	r.GET("/.well-known/healthcheck.json", gin.WrapF(ms.HealthCheckHandler()))
	r.GET("/admin/healthcheck.json", gin.WrapF(ms.HealthCheckHandler()))
	r.GET("/admin/stats.json", gin.WrapF(ms.StatsHandler()))
	r.GET("/admin/other.json", gin.WrapF(ms.StatsHandler()))
	r.GET("/merp/for/:thing", tollbooth_gin.LimitHandler(limiter), ms.handleNewMerp())
	r.GET("/get/latest/merp/for/:thing", tollbooth_gin.LimitHandler(limiter), ms.getLatestMerps())
	r.GET("/get/latest/merps", tollbooth_gin.LimitHandler(limiter), ms.getLatestMerps())
	r.GET("/get/merps/for/:thing", tollbooth_gin.LimitHandler(limiter), ms.getLatestMerps())

	ms.gin = r
}