Allow vtbackup to run as a daemon

go/cmd/tools.go

@@ -0,0 +1,43 @@
+/*
+Copyright 2019 The Vitess Authors
+
+Licensed under the Apache License, Version 2.0 (the "License");
+you may not use this file except in compliance with the License.
+You may obtain a copy of the License at
+
+    http://www.apache.org/licenses/LICENSE-2.0
+
+Unless required by applicable law or agreed to in writing, software
+distributed under the License is distributed on an "AS IS" BASIS,
+WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
+See the License for the specific language governing permissions and
+limitations under the License.
+*/
+package cmd
+
+import (
+	"fmt"
+	"os"
+	"os/exec"
+	"strings"
+)
+
+// DetachFromTerminalAndExit allows a command line program to detach from the terminal and continue running
+// even if the parent process is terminated
+func DetachFromTerminalAndExit() {
+	args := os.Args[1:]
+	i := 0
+	for ; i < len(args); i++ {
+		if strings.HasPrefix(args[i], "-detach") {
+			args[i] = "-detach=false"
+			break
+		}
+	}
+	cmd := exec.Command(os.Args[0], args...)
+	cmd.Stdin = os.Stdin
+	cmd.Stdout = os.Stdout
+	cmd.Stderr = os.Stderr
+	_ = cmd.Start()
+	fmt.Println("[PID]", cmd.Process.Pid)
+	os.Exit(0)
+}

go/cmd/vtbackup/vtbackup.go

@@ -70,6 +70,7 @@ import (
 	"syscall"
 	"time"
 
+	"vitess.io/vitess/go/cmd"
 	"vitess.io/vitess/go/exit"
 	"vitess.io/vitess/go/mysql"
 	"vitess.io/vitess/go/sqlescape"
@@ -124,17 +125,23 @@ var (
 	mysqlSocket   = flag.String("mysql_socket", "", "path to the mysql socket")
 	mysqlTimeout  = flag.Duration("mysql_timeout", 5*time.Minute, "how long to wait for mysqld startup")
 	initDBSQLFile = flag.String("init_db_sql_file", "", "path to .sql file to run after mysql_install_db")
+	detachedMode  = flag.Bool("detach", false, "detached mode - run backups detached from the terminal")
 )
 
 func main() {
 	defer exit.Recover()
-	defer logutil.Flush()
-
 	dbconfigs.RegisterFlags(dbconfigs.All...)
 	mysqlctl.RegisterFlags()
 
 	servenv.ParseFlags("vtbackup")
 
+	if *detachedMode {
+		// this method will call os.Exit and kill this process
+		cmd.DetachFromTerminalAndExit()
+	}
+
+	defer logutil.Flush()
+
 	if *minRetentionCount < 1 {
 		log.Errorf("min_retention_count must be at least 1 to allow restores to succeed")
 		exit.Return(1)

go/cmd/vtctl/vtctl.go

@@ -26,6 +26,8 @@ import (
 	"syscall"
 	"time"
 
+	"vitess.io/vitess/go/cmd"
+
 	"golang.org/x/net/context"
 	"vitess.io/vitess/go/exit"
 	"vitess.io/vitess/go/trace"
@@ -40,7 +42,8 @@ import (
 )
 
 var (
-	waitTime = flag.Duration("wait-time", 24*time.Hour, "time to wait on an action")
+	waitTime     = flag.Duration("wait-time", 24*time.Hour, "time to wait on an action")
+	detachedMode = flag.Bool("detach", false, "detached mode - run vtcl detached from the terminal")
 )
 
 func init() {
@@ -70,6 +73,11 @@ func main() {
 	defer exit.RecoverAll()
 	defer logutil.Flush()
 
+	if *detachedMode {
+		// this method will call os.Exit and kill this process
+		cmd.DetachFromTerminalAndExit()
+	}
+
 	args := servenv.ParseFlagsWithArgs("vtctl")
 	action := args[0]