main.go

package main

import (
	"flag"
	"fmt"
	"net"
	"net/http"
	"os"
	"os/signal"
	"syscall"

	"github.com/TUB-CNPE-TB/user/api"
	"github.com/TUB-CNPE-TB/user/db"
	"github.com/TUB-CNPE-TB/user/db/mongodb"
	"github.com/go-kit/kit/log"
	stdopentracing "github.com/opentracing/opentracing-go"
	stdprometheus "github.com/prometheus/client_golang/prometheus"
)

var (
	port string
	zip  string
)

var (
	HTTPLatency = stdprometheus.NewHistogramVec(stdprometheus.HistogramOpts{
		Name:    "http_request_duration_seconds",
		Help:    "Time (in seconds) spent serving HTTP requests.",
		Buckets: stdprometheus.DefBuckets,
	}, []string{"method", "path", "status_code", "isWS"})
)

const (
	ServiceName = "user"
)

func init() {
	stdprometheus.MustRegister(HTTPLatency)
	flag.StringVar(&zip, "zipkin", os.Getenv("ZIPKIN"), "Zipkin address")
	flag.StringVar(&port, "port", "8084", "Port on which to run")
	db.Register("mongodb", &mongodb.Mongo{})
}

func main() {

	flag.Parse()
	// Mechanical stuff.
	errc := make(chan error)

	// Log domain.
	var logger log.Logger
	{
		logger = log.NewLogfmtLogger(log.NewSyncWriter(os.Stdout))
		logger = log.With(logger, "ts", log.DefaultTimestampUTC)
		logger = log.With(logger, "caller", log.DefaultCaller)
	}

	// Find service local IP.
	conn, err := net.Dial("udp", "8.8.8.8:80")
	if err != nil {
		_ = logger.Log("msg", "Unable to find service local IP", "error", err)
		os.Exit(1)
	} else {
		_ = logger.Log("local_ip", conn.LocalAddr())
	}
	//localAddr := conn.LocalAddr().(*net.UDPAddr)
	//host := strings.Split(localAddr.String(), ":")[0]
	defer conn.Close()

	var tracer stdopentracing.Tracer
	{
		if zip == "" {
			_ = logger.Log("zipkin_status", "No tracer")
			tracer = stdopentracing.NoopTracer{}
		}
		stdopentracing.InitGlobalTracer(tracer)
	}

	dbconn := false
	for !dbconn {
		err := db.Init()
		if err != nil {
			if err == db.ErrNoDatabaseSelected {
				_ = logger.Log("db_conn", "No database selected", "error", err)
				os.Exit(1)
			}
			_ = logger.Log("db_conn", "Database init failed", "error", err)
		} else {
			dbconn = true
		}
	}

	// Service domain.
	var service api.Service
	{
		service = api.NewFixedService()
		service = api.LoggingMiddleware(logger)(service)
	}

	// Endpoint domain.
	endpoints := api.MakeEndpoints(service, tracer)

	// HTTP router
	router := api.MakeHTTPHandler(endpoints, logger, tracer)

	// Create and launch the HTTP server.
	go func() {
		_ = logger.Log("transport", "HTTP", "port", port)
		errc <- http.ListenAndServe(fmt.Sprintf(":%v", port), router)
	}()

	// Capture interrupts.
	go func() {
		c := make(chan os.Signal)
		signal.Notify(c, syscall.SIGINT, syscall.SIGTERM)
		errc <- fmt.Errorf("%s", <-c)
	}()

	_ = logger.Log("exit", <-errc)
}