br: add lock file

pkg/backup/client.go

@@ -122,6 +122,13 @@ func (bc *Client) GetTS(ctx context.Context, duration time.Duration, ts uint64)
 	return backupTS, nil
 }
 
+// SetLockFile set write lock file.
+func (bc *Client) SetLockFile(ctx context.Context) error {
+	return bc.storage.Write(ctx, utils.LockFile,
+		[]byte("DO NOT DELETE\n"+
+			"This file exists to remind other backup jobs won't use this path"))
+}
+
 // SetGCTTL set gcTTL for client.
 func (bc *Client) SetGCTTL(ttl int64) {
 	bc.gcTTL = ttl
@@ -147,6 +154,13 @@ func (bc *Client) SetStorage(ctx context.Context, backend *kvproto.StorageBacken
 	if exist {
 		return errors.New("backup meta exists, may be some backup files in the path already")
 	}
+	exist, err = bc.storage.FileExists(ctx, utils.LockFile)
+	if err != nil {
+		return errors.Annotatef(err, "error occurred when checking %s file", utils.LockFile)
+	}
+	if exist {
+		return errors.New("backup lock exists, may be some backup files in the path already")
+	}
 	bc.backend = backend
 	return nil
 }

pkg/task/backup.go

@@ -125,6 +125,10 @@ func RunBackup(c context.Context, g glue.Glue, cmdName string, cfg *BackupConfig
 	if err = client.SetStorage(ctx, u, cfg.SendCreds); err != nil {
 		return err
 	}
+	err = client.SetLockFile(ctx)
+	if err != nil {
+		return err
+	}
 	client.SetGCTTL(cfg.GCTTL)
 
 	backupTS, err := client.GetTS(ctx, cfg.TimeAgo, cfg.BackupTS)

pkg/utils/schema.go

@@ -14,6 +14,8 @@ import (
 )
 
 const (
+	// LockFile represents file name,
+	LockFile = "backup.lock"
 	// MetaFile represents file name
 	MetaFile = "backupmeta"
 	// MetaJSONFile represents backup meta json file name

tests/br_other/run.sh

@@ -20,12 +20,14 @@ run_sql "CREATE DATABASE $DB;"
 
 run_sql "CREATE TABLE $DB.usertable1 ( \
   YCSB_KEY varchar(64) NOT NULL, \
-  FIELD0 varchar(1) DEFAULT NULL, \
+  FIELD0 varchar(10) DEFAULT NULL, \
   PRIMARY KEY (YCSB_KEY) \
 ) ENGINE=InnoDB DEFAULT CHARSET=utf8mb4 COLLATE=utf8mb4_bin;"
 
-run_sql "INSERT INTO $DB.usertable1 VALUES (\"a\", \"b\");"
-run_sql "INSERT INTO $DB.usertable1 VALUES (\"aa\", \"b\");"
+for i in `seq 1 100`
+do
+run_sql "INSERT INTO $DB.usertable1 VALUES (\"a$i\", \"bbbbbbbbbb\");"
+done
 
 # backup full
 echo "backup start..."
@@ -52,6 +54,30 @@ if [ "$corrupted" -ne "1" ];then
     exit 1
 fi
 
+# backup full with ratelimit = 1 to make sure this backup task won't finish quickly
+echo "backup start to test lock file"
+run_br --pd $PD_ADDR backup full -s "local://$TEST_DIR/$DB/lock" --ratelimit 1 --ratelimit-unit 1 --concurrency 4 > /dev/null 2>&1 &
+# record last backup pid
+_pid=$!
+
+backup_fail=0
+echo "another backup start expect to fail due to last backup add a lockfile"
+run_br --pd $PD_ADDR backup full -s "local://$TEST_DIR/$DB/lock" --concurrency 4 || backup_fail=1
+if [ "$backup_fail" -ne "1" ];then
+    echo "TEST: [$TEST_NAME] test backup lock file failed!"
+    exit 1
+fi
+
+if ps -p $_pid > /dev/null
+then
+   echo "$_pid is running"
+   # kill last backup progress
+   kill -9 $_pid
+else
+   echo "TEST: [$TEST_NAME] test backup lock file failed! the last backup finished"
+   exit 1
+fi
+
 run_sql "DROP DATABASE $DB;"
 
 # Test version