Merge pull request #26 from fourcube/add-version-and-pidfile-arguments

Add `-v` and `-pidFile` arguments

VERSION

@@ -0,0 +1 @@
+1.0.1

build.sh

@@ -10,6 +10,8 @@ CONFIGURATIONS=(
     solaris,amd64
 )
 
+version=`cat VERSION`
+
 for config in ${CONFIGURATIONS[@]}; do 
 IFS=","
 set $config
@@ -25,10 +27,10 @@ if [ $os = "windows" ]; then
     bin_name="$bin_name.exe"
 fi
 
-GOOS="$os" GOARCH="$arch" go build -o "$path/$bin_name"
+GOOS="$os" GOARCH="$arch" go build -ldflags "-X main.Version=${version}" -o "$path/$bin_name"
 cp -r $GOPATH/src/github.com/fourcube/goiban-data-loader/data "$path/"
 cp -r ./static "$path/"
-tar czvf "build/goiban-service-$os-$arch.tar.gz" -C "$base_path" goiban-service
+tar czvf "build/goiban-service-$version-$os-$arch.tar.gz" -C "$base_path" goiban-service
 
 unset IFS;
 done

goiban_service.go

@@ -1,12 +1,14 @@
 package main
 
 import (
+	"context"
 	"encoding/json"
 	"flag"
 	"fmt"
 	"log"
 	"net/http"
 	"os"
+	"os/signal"
 	"path/filepath"
 	"strconv"
 	"strings"
@@ -42,22 +44,28 @@ var (
 	metrics      *m.KeenMetrics
 	inmemMetrics = m.NewInmemMetricsRegister()
 	repo         data.BankDataRepository
+	// Set at link time
+	Version string = "dev"
 	// Flags
-	dataPath   string
-	staticPath string
-	mysqlURL   string
-	port       string
-	help       bool
-	web        bool
+	dataPath     string
+	staticPath   string
+	mysqlURL     string
+	pidFile      string
+	port         string
+	help         bool
+	web          bool
+	printVersion bool
 )
 
 func init() {
 	flag.StringVar(&dataPath, "dataPath", "", "Base path of the bank data")
 	flag.StringVar(&staticPath, "staticPath", "", "Base path of the static web content")
 	flag.StringVar(&mysqlURL, "dbUrl", "", "Database connection string")
+	flag.StringVar(&pidFile, "pidFile", "", "PID File path")
 
 	flag.StringVar(&port, "port", "8080", "HTTP Port or interface to listen on")
 	flag.BoolVar(&help, "h", false, "Show usage")
+	flag.BoolVar(&printVersion, "v", false, "Show version")
 	flag.BoolVar(&web, "w", false, "Serve staticPath folder")
 }
 
@@ -69,6 +77,15 @@ func main() {
 		return
 	}
 
+	if printVersion {
+		fmt.Println(Version)
+		return
+	}
+
+	if pidFile != "" {
+		CreatePidfile(pidFile)
+	}
+
 	if web && staticPath == "" {
 		// Try to serve from the package src directory
 		path := filepath.Join(os.Getenv("GOPATH"), "src", "github.com", "fourcube", "goiban-service", "static")
@@ -126,23 +143,48 @@ func listen() {
 	listeningInfo := "Listening on %s"
 	handler := corsHandler.Handler(router)
 
+	var server http.Server
+	var addr string
+
+	idleConnsClosed := make(chan struct{})
+	go func() {
+		sigint := make(chan os.Signal, 1)
+		signal.Notify(sigint, os.Interrupt)
+		<-sigint
+
+		log.Printf("Received SIGINT. Waiting for connections to close...")
+
+		// We received an interrupt signal, shut down.
+		if err := server.Shutdown(context.Background()); err != nil {
+			// Error from closing listeners, or context timeout:
+			log.Printf("HTTP server Shutdown: %v", err)
+		}
+		close(idleConnsClosed)
+	}()
+
 	if strings.ContainsAny(port, ":") {
 		if web {
 			listeningInfo = fmt.Sprintf(listeningInfo, "%s (serving static content from '/').")
 		}
-		log.Printf(listeningInfo, port)
-		err = http.ListenAndServe(port, handler)
+		addr = port
 	} else {
 		if web {
 			listeningInfo = fmt.Sprintf(listeningInfo, ":%s (serving static content from '/').")
 		}
-		log.Printf(listeningInfo, port)
-		err = http.ListenAndServe(":"+port, handler)
+		addr = ":" + port
 	}
 
-	if err != nil {
+	server.Handler = handler
+	server.Addr = addr
+
+	log.Printf("goiban-service (v%s)", Version)
+	log.Printf(listeningInfo, port)
+
+	if err := server.ListenAndServe(); err != http.ErrServerClosed {
 		log.Fatal("ListenAndServe: ", err)
 	}
+
+	<-idleConnsClosed
 }
 
 // Processes requests to the /validate/ url

pid.go

@@ -0,0 +1,66 @@
+package main
+
+import (
+	"fmt"
+	"io/ioutil"
+	"log"
+	"os"
+	"path/filepath"
+	"strconv"
+	"syscall"
+)
+
+// CreatePidfile creates a pidfile.
+// If the file already exists, it checks if the process is already running and terminates.
+func CreatePidfile(pidFile string) {
+	if pidFile != "" {
+		if err := os.MkdirAll(filepath.Dir(pidFile), os.FileMode(0755)); err != nil {
+			log.Fatalf("Could not create path to pidfile %v", err)
+		}
+
+		if _, err := os.Stat(pidFile); err != nil && !os.IsNotExist(err) {
+			log.Fatalf("Failed to stat pidfile %v", err)
+		}
+
+		f, err := os.OpenFile(pidFile, os.O_CREATE|os.O_RDWR, 0644)
+		if err != nil {
+			log.Fatalf("Failed to open pidfile %v", err)
+		}
+		defer f.Close()
+
+		if pidBytes, err := ioutil.ReadAll(f); err != nil {
+			log.Fatalf("Failed to read from pidfile %v")
+		} else {
+			if len(pidBytes) == 0 {
+				goto foo
+			}
+
+			pid, err := strconv.Atoi(string(pidBytes))
+			if err != nil {
+				log.Fatalf("Invalid pid %v", err)
+			}
+
+			process, err := os.FindProcess(pid)
+			if err != nil {
+				log.Fatalf("Failed to find process %v, please delete the pid file %s manually", err, pidFile)
+			}
+
+			if err := process.Signal(syscall.Signal(0)); err == nil {
+				log.Fatalf("Process %d still running, please stop the process and delete the pid file %s manually", pid, pidFile)
+			}
+		}
+
+	foo:
+		if err = f.Truncate(0); err != nil {
+			log.Fatalf("Failed to truncate pidfile", err)
+		}
+		if _, err = f.Seek(0, 0); err != nil {
+			log.Fatalf("Failed to seek pidfile", err)
+		}
+
+		_, err = fmt.Fprintf(f, "%d", os.Getpid())
+		if err != nil {
+			log.Fatalf("Failed to write pidfile %v", err)
+		}
+	}
+}