implementato la scrittura e il controllo del PID per verificare se e' gia' running

llmongo.go

@@ -8,6 +8,8 @@ import (
 	"gopkg.in/mgo.v2"
 	"os"
 	//    "gopkg.in/mgo.v2/bson"
+	"bytes"
+	"io/ioutil"
 	"log"
 	"path"
 	"path/filepath"
@@ -23,7 +25,10 @@ type Options struct {
 	mdb         *mgo.Session
 	ll          *mgo.Collection
 	RedisTTL    time.Duration
+	CurrentPath string
+	Exe         string
 	LogFile     string
+	PIDFile     string
 	Version     bool
 }
 
@@ -60,14 +65,15 @@ func usage() {
 }
 
 func init() {
-	current, err := filepath.Abs(filepath.Dir(os.Args[0]))
+	var err error
+	opts.CurrentPath, err = filepath.Abs(filepath.Dir(os.Args[0]))
 	if err != nil {
 		log.Fatal(err)
 	}
 
-	opts.LogFile = path.Join(current, opts.LogFile)
-
-	//	fmt.Println(opts.LogFile)
+	opts.LogFile = path.Join(opts.CurrentPath, opts.LogFile)
+	opts.PIDFile = path.Join(opts.CurrentPath, "run", path.Base(os.Args[0])+".pid")
+	opts.Exe = path.Base(os.Args[0])
 
 	flag.StringVar(&opts.MongoUri, "m", opts.MongoUri, "Mongodb")
 	flag.StringVar(&opts.RedisUri, "r", opts.RedisUri, "Redis")
@@ -95,6 +101,26 @@ func connectMongo() {
 	opts.ll = opts.mdb.DB("dovecot").C("lastlogin")
 }
 
+func checkPID(bpid []byte) bool {
+	pid := strings.TrimRight(string(bpid), "\n")
+	fmt.Println("PID: ", pid)
+	bcmd, err := ioutil.ReadFile(path.Join("/proc", pid, "cmdline"))
+	if err != nil {
+		fmt.Println("cmdline error: ", err)
+		return false
+	}
+	cmd := bytes.Trim(bcmd, "\x00")
+	fmt.Println(string(cmd), opts.Exe)
+	if strings.Contains(string(cmd), opts.Exe) {
+		return true
+	}
+	return true
+}
+
+func writePID() {
+
+}
+
 func main() {
 	flag.Usage = usage
 	flag.Parse()
@@ -104,6 +130,22 @@ func main() {
 		os.Exit(0)
 	}
 
+	if bpid, err := ioutil.ReadFile(opts.PIDFile); err == nil && checkPID(bpid) {
+		fmt.Println("Running: ", string(bpid))
+		os.Exit(-6)
+	} else {
+		fpid, err := os.OpenFile(opts.PIDFile, os.O_WRONLY|os.O_CREATE, 0666)
+		if err != nil {
+			fmt.Println("PID file error: ", err.Error())
+			os.Exit(-5)
+		}
+		fpid.WriteString(strconv.Itoa(os.Getpid()))
+		fpid.Close()
+	}
+	defer os.Remove(opts.PIDFile)
+
+	fmt.Println(os.Stat(opts.PIDFile))
+
 	fs, err := os.OpenFile(opts.LogFile, os.O_WRONLY|os.O_APPEND|os.O_CREATE, 0666)
 	if err != nil {
 		fmt.Println("Log file error: ", err.Error())