[feature] Added systemd support

Makefile

@@ -7,7 +7,7 @@ race:
 	go run --race cmd/server/main.go
 
 build:
-	go build -o build/server cmd/server/main.go
+	GOOS=linux GOARCH=amd64 go build -o build/server cmd/server/main.go
 
 test:
 	go test -v -run=. test/**/*.go

init/api-server.service

@@ -0,0 +1,17 @@
+#FIXME: FIX PATHS
+
+[Unit]
+Requires=network-online.target
+After=network-online.target
+Requires=api-server.socket
+
+[Service]
+ExecStart=/home/keedosn/go/src/git.pbiernat.dev/api-prototype/build/server
+WorkingDirectory=/home/keedosn/go/src/git.pbiernat.dev/api-prototype
+User=keedosn
+Group=keedosn
+NonBlocking=true
+StandardOutput=append:/home/keedosn/go/src/git.pbiernat.dev/api-prototype/build/err.log
+StandardError=append:/home/keedosn/go/src/git.pbiernat.dev/api-prototype/build/err.log
+SyslogIdentifier=api-server
+

init/api-server.socket

@@ -0,0 +1,7 @@
+[Unit]
+Description=API Server socket
+
+[Socket]
+ListenStream=10080
+NoDelay=true
+

internal/app/server.go

@@ -5,7 +5,10 @@ import (
 	"encoding/json"
 	"io/ioutil"
 	"log"
+	"net"
 	"net/http"
+	"os"
+	"strconv"
 	"time"
 
 	def "git.pbiernat.dev/golang/rest-api-prototype/internal/app/definition"
@@ -30,8 +33,18 @@ func NewServer(env *handler.Env) *Server {
 
 func (s *Server) Start() {
 	log.Println("Server listening on " + s.Addr)
-	if err := s.ListenAndServe(); err != nil {
-		log.Println(err)
+
+	if os.Getenv("LISTEN_PID") == strconv.Itoa(os.Getpid()) {
+		// systemd run
+		f := os.NewFile(3, "from systemd")
+		l, err := net.FileListener(f)
+		if err != nil {
+			log.Fatalln(err)
+		}
+		http.Serve(l, nil)
+	} else {
+		// manual run
+		log.Fatalln(s.ListenAndServe())
 	}
 }