introduced pidfile

chocon.go

@@ -14,6 +14,7 @@ import (
 	"github.com/fukata/golang-stats-api-handler"
 	"github.com/jessevdk/go-flags"
 	"github.com/kazeburo/chocon/accesslog"
+	"github.com/kazeburo/chocon/pidfile"
 	"github.com/kazeburo/chocon/proxy"
 	"github.com/kazeburo/chocon/upstream"
 	"github.com/lestrrat/go-server-starter-listener"
@@ -32,6 +33,7 @@ type cmdOpts struct {
 	LogDir           string `long:"access-log-dir" default:"" description:"directory to store logfiles"`
 	LogRotate        int64  `long:"access-log-rotate" default:"30" description:"Number of day before remove logs"`
 	Version          bool   `short:"v" long:"version" description:"Show version"`
+	PidFile          string `long:"pid-file" default:"" description:"filename to store pid. disabled by default"`
 	KeepaliveConns   int    `short:"c" default:"2" long:"keepalive-conns" description:"maximum keepalive connections for upstream"`
 	MaxConnsPerHost  int    `long:"max-conns-per-host" default:"0" description:"maximum connections per host"`
 	ReadTimeout      int    `long:"read-timeout" default:"30" description:"timeout of reading request"`
@@ -118,6 +120,13 @@ func main() {
 		log.Fatal(err)
 	}
 
+	if opts.PidFile != "" {
+		err = pidfile.WritePid(opts.PidFile)
+		if err != nil {
+			log.Fatal(err)
+		}
+	}
+
 	transport := makeTransport(opts.KeepaliveConns, opts.MaxConnsPerHost, opts.ProxyReadTimeout)
 	var handler http.Handler = proxy.New(&transport, Version, upstream, logger)
 

pidfile/pidfile.go

@@ -0,0 +1,30 @@
+package pidfile
+
+import (
+	"fmt"
+	"io/ioutil"
+	"os"
+	"path/filepath"
+
+	"github.com/pkg/errors"
+)
+
+// WritePid : write pid to given file
+func WritePid(pidfile string) error {
+	dir, filename := filepath.Split(pidfile)
+	tmpfile, err := ioutil.TempFile(dir, filename+".*")
+	if err != nil {
+		return errors.Wrap(err, "Cloud not create tempfile")
+	}
+	_, err = tmpfile.WriteString(fmt.Sprintf("%d", os.Getpid()))
+	if err != nil {
+		tmpfile.Close()
+		return errors.Wrap(err, "Cloud not write pid to tempfile")
+	}
+	tmpfile.Close()
+	err = os.Rename(tmpfile.Name(), pidfile)
+	if err != nil {
+		return errors.Wrap(err, "Cloud not rename pidfile")
+	}
+	return nil
+}