feta/process/server.go

package process

import "fmt"
import "net/http"
import "os"
import "strconv"
import "time"

import "github.com/rs/zerolog/log"
import "github.com/gin-gonic/gin"
import "github.com/dn365/gin-zerolog"

// Server is the HTTP webserver object
type Server struct {
	feta   *Feta
	port   uint
	router *gin.Engine
	server *http.Server
	debug  bool
}

// SetFeta tells the http Server where to find the Process object so that it
// can pull stats and other information for serving via http
func (a *Server) SetFeta(feta *Feta) {
	a.feta = feta
}

// Serve is the entrypoint for the Server, which should run in its own
// goroutine (started by the Process)
func (a *Server) Serve() {
	if a.feta == nil {
		panic("must have feta app from which to serve stats")
	}

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

	a.port = 8080

	if os.Getenv("PORT") != "" {
		s, err := strconv.ParseUint(os.Getenv("PORT"), 10, 64)
		if err != nil {
			a.port = uint(s)
		}
	}

	a.initRouter()
	a.initServer()
	err := a.server.ListenAndServe()

	if err != nil {
		log.Fatal().Err(err).Msg("webserver failure")
		return
	}
}

func (a *Server) initRouter() {

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

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

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

	r.GET("/.well-known/healthcheck.json", gin.WrapF(a.getHealthCheckHandler()))
	r.GET("/", func(c *gin.Context) { c.Redirect(http.StatusMovedPermanently, "/feta") })
	r.GET("/feta", gin.WrapF(a.getIndexHandler()))
	r.GET("/feta/list/instances", gin.WrapF(a.getInstanceListHandler()))

	a.router = r
}

func (a *Server) initServer() {
	if !a.debug {
		gin.SetMode(gin.ReleaseMode)
	}

	log.Info().Uint("port", a.port).Msg("starting webserver")

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