unlock and sync secondary (#1975)

Signed-off-by: sayedppqq <sayed@appscode.com>

Author: sayedppqq

pkg/backup.go

@@ -442,7 +442,7 @@ func (opt *mongoOptions) backupMongoDB(targetRef api_v1beta1.TargetRef) (*restic
 
 	if parameters.ConfigServer != "" {
 		// sharded cluster. so disable the balancer first. then perform the 'usual' tasks.
-		primary, secondary, err := getPrimaryNSecondaryMember(parameters.ConfigServer)
+		primary, secondary, secondaryMembers, err := getPrimaryNSecondaryMember(parameters.ConfigServer)
 		if err != nil {
 			return nil, err
 		}
@@ -464,7 +464,19 @@ func (opt *mongoOptions) backupMongoDB(targetRef api_v1beta1.TargetRef) (*restic
 			backupHost = secondary
 		}
 
-		err = lockConfigServer(parameters.ConfigServer, secondary)
+		// Check if secondary is already locked before locking it.
+		// If yes, unlock it and sync with primary
+		for _, secondary := range secondaryMembers {
+			if err := checkIfSecondaryLockedAndSync(secondary); err != nil {
+				return nil, err
+			}
+		}
+
+		if err := setupConfigServer(parameters.ConfigServer, secondary); err != nil {
+			return nil, err
+		}
+
+		err = lockSecondaryMember(secondary)
 
 		cleanupFuncs = append(cleanupFuncs, func() error {
 			// even if error occurs, try to unlock the server
@@ -479,7 +491,7 @@ func (opt *mongoOptions) backupMongoDB(targetRef api_v1beta1.TargetRef) (*restic
 
 	for key, host := range parameters.ReplicaSets {
 		// do the task
-		primary, secondary, err := getPrimaryNSecondaryMember(host)
+		primary, secondary, secondaryMembers, err := getPrimaryNSecondaryMember(host)
 		if err != nil {
 			klog.Errorf("error while getting primary and secondary member of %v. error: %v", host, err)
 			return nil, err
@@ -492,6 +504,14 @@ func (opt *mongoOptions) backupMongoDB(targetRef api_v1beta1.TargetRef) (*restic
 			backupHost = secondary
 		}
 
+		// Check if secondary is already locked before locking it.
+		// If yes, unlock it and sync with primary
+		for _, secondary := range secondaryMembers {
+			if err := checkIfSecondaryLockedAndSync(secondary); err != nil {
+				return nil, err
+			}
+		}
+
 		err = lockSecondaryMember(secondary)
 		cleanupFuncs = append(cleanupFuncs, func() error {
 			// even if error occurs, try to unlock the server
@@ -573,11 +593,10 @@ func getSSLUser(path string) (string, error) {
 	return strings.TrimSpace(user), nil
 }
 
-func getPrimaryNSecondaryMember(mongoDSN string) (primary, secondary string, err error) {
+func getPrimaryNSecondaryMember(mongoDSN string) (primary, secondary string, secondaryMembers []string, err error) {
 	klog.Infoln("finding primary and secondary instances of", mongoDSN)
 	v := make(map[string]interface{})
 
-	// stop balancer
 	args := append([]interface{}{
 		"config",
 		"--host", mongoDSN,
@@ -586,33 +605,35 @@ func getPrimaryNSecondaryMember(mongoDSN string) (primary, secondary string, err
 	}, mongoCreds...)
 	// even --quiet doesn't skip replicaset PrimaryConnection log. so take tha last line. issue tracker: https://jira.mongodb.org/browse/SERVER-27159
 	if err := sh.Command(MongoCMD, args...).Command("/usr/bin/tail", "-1").UnmarshalJSON(&v); err != nil {
-		return "", "", err
+		return "", "", secondaryMembers, err
 	}
 
 	primary, ok := v["primary"].(string)
 	if !ok || primary == "" {
-		return "", "", fmt.Errorf("unable to get primary instance using rs.isMaster(). got response: %v", v)
+		return "", "", secondaryMembers, fmt.Errorf("unable to get primary instance using rs.isMaster(). got response: %v", v)
 	}
 
 	hosts, ok := v["hosts"].([]interface{})
 	if !ok {
-		return "", "", fmt.Errorf("unable to get hosts using rs.isMaster(). got response: %v", v)
+		return "", "", secondaryMembers, fmt.Errorf("unable to get hosts using rs.isMaster(). got response: %v", v)
 	}
 
 	for _, host := range hosts {
-		secHost, ok := host.(string)
-		if !ok || secHost == "" {
+		curHost, ok := host.(string)
+
+		if !ok || curHost == "" {
 			err = fmt.Errorf("unable to get secondary instance using rs.isMaster(). got response: %v", v)
 			continue
 		}
-
-		if secHost != primary {
-			klog.Infof("Primary %s & Secondary %s found for mongoDSN %s \n", primary, secHost, mongoDSN)
-			return primary, secHost, nil
+		if curHost != primary {
+			secondaryMembers = append(secondaryMembers, curHost)
 		}
 	}
+	if len(secondaryMembers) > 0 {
+		return primary, secondaryMembers[0], secondaryMembers, err
+	}
 
-	return primary, "", err
+	return primary, "", secondaryMembers, err
 }
 
 // run from mongos instance
@@ -699,141 +720,3 @@ func enableBalancer(mongosHost string) error {
 	klog.Info("Balancer successfully re-enabled.")
 	return nil
 }
-
-func lockConfigServer(configSVRDSN, secondaryHost string) error {
-	klog.Infoln("Attempting to lock configserver", configSVRDSN)
-
-	if secondaryHost == "" {
-		klog.Warningln("locking configserver is skipped. secondary host is empty")
-		return nil
-	}
-	v := make(map[string]interface{})
-	// findAndModify BackupControlDocument. skip single quote inside single quote: https://stackoverflow.com/a/28786747/4628962
-	args := append([]interface{}{
-		"config",
-		"--host", configSVRDSN,
-		"--quiet",
-		"--eval", "db.BackupControl.findAndModify({query: { _id: 'BackupControlDocument' }, update: { $inc: { counter : 1 } }, new: true, upsert: true, writeConcern: { w: 'majority', wtimeout: 15000 }});",
-	}, mongoCreds...)
-
-	output, err := sh.Command(MongoCMD, args...).Output()
-	if err != nil {
-		klog.Errorf("Error while running findAndModify to lock configServer : %s ; output : %s \n", err.Error(), output)
-		return err
-	}
-	s := fmt.Sprintf(`/bin/echo '%s' | /usr/bin/tail -1`, strings.TrimSuffix(string(output), "\n"))
-	output, err = sh.Command("/bin/sh", "-c", s).Output()
-	if err != nil {
-		klog.Errorf("Error while running tail in findAndModify to lock configServer : %s ; output : %s \n", err.Error(), output)
-		return err
-	}
-
-	err = json.Unmarshal(output, &v)
-	if err != nil {
-		klog.Errorf("Unmarshal error while running findAndModify to lock configServer : %s \n", err.Error())
-		return err
-	}
-	val, ok := v["counter"].(float64)
-	if !ok || int(val) == 0 {
-		return fmt.Errorf("unable to modify BackupControlDocument. got response: %v", v)
-	}
-	val2 := float64(0)
-	timer := 0 // wait approximately 5 minutes.
-	for timer < 60 && (int(val2) == 0 || int(val) != int(val2)) {
-		timer++
-		// find backupDocument from secondary configServer
-		args = append([]interface{}{
-			"config",
-			"--host", secondaryHost,
-			"--quiet",
-			"--eval", "rs.slaveOk(); db.BackupControl.find({ '_id' : 'BackupControlDocument' }).readConcern('majority');",
-		}, mongoCreds...)
-
-		if err := sh.Command(MongoCMD, args...).UnmarshalJSON(&v); err != nil {
-			return err
-		}
-
-		val2, ok = v["counter"].(float64)
-		if !ok {
-			return fmt.Errorf("unable to get BackupControlDocument. got response: %v", v)
-		}
-		if int(val) != int(val2) {
-			klog.V(5).Infof("BackupDocument counter in secondary is not same. Expected %v, but got %v. Full response: %v", val, val2, v)
-			time.Sleep(time.Second * 5)
-		}
-	}
-	if timer >= 60 {
-		return fmt.Errorf("timeout while waiting for BackupDocument counter in secondary to be same as primary. Expected %v, but got %v. Full response: %v", val, val2, v)
-	}
-	// lock secondary
-	return lockSecondaryMember(secondaryHost)
-}
-
-func lockSecondaryMember(mongohost string) error {
-	klog.Infoln("Attempting to lock secondary member", mongohost)
-	if mongohost == "" {
-		klog.Warningln("locking secondary member is skipped. secondary host is empty")
-		return nil
-	}
-	v := make(map[string]interface{})
-
-	// lock file
-	args := append([]interface{}{
-		"config",
-		"--host", mongohost,
-		"--quiet",
-		"--eval", "JSON.stringify(db.fsyncLock())",
-	}, mongoCreds...)
-
-	output, err := sh.Command(MongoCMD, args...).Output()
-	if err != nil {
-		klog.Errorf("Error while running fsyncLock on secondary : %s ; output : %s \n", err.Error(), output)
-		return err
-	}
-
-	err = json.Unmarshal(output, &v)
-	if err != nil {
-		klog.Errorf("Unmarshal error while running fsyncLock on secondary : %s \n", err.Error())
-		return err
-	}
-
-	if val, ok := v["ok"].(float64); !ok || int(val) != 1 {
-		return fmt.Errorf("unable to lock the secondary host. got response: %v", v)
-	}
-	klog.Infof("secondary %s locked.", mongohost)
-	return nil
-}
-
-func unlockSecondaryMember(mongohost string) error {
-	klog.Infoln("Attempting to unlock secondary member", mongohost)
-	if mongohost == "" {
-		klog.Warningln("skipped unlocking secondary member. secondary host is empty")
-		return nil
-	}
-	v := make(map[string]interface{})
-
-	// unlock file
-	args := append([]interface{}{
-		"config",
-		"--host", mongohost,
-		"--quiet",
-		"--eval", "JSON.stringify(db.fsyncUnlock())",
-	}, mongoCreds...)
-
-	output, err := sh.Command(MongoCMD, args...).Output()
-	if err != nil {
-		klog.Errorf("Error while running fsyncUnlock on secondary : %s ; output : %s \n", err.Error(), output)
-		return err
-	}
-	err = json.Unmarshal(output, &v)
-	if err != nil {
-		klog.Errorf("Unmarshal error while running fsyncUnlock on secondary : %s \n", err.Error())
-		return err
-	}
-
-	if val, ok := v["ok"].(float64); !ok || int(val) != 1 {
-		return fmt.Errorf("unable to lock the secondary host. got response: %v", v)
-	}
-	klog.Infof("secondary %s unlocked.", mongohost)
-	return nil
-}