node: switching prometheus flock location to tsdb (#19376)

* node: switching prometheus flock location to tsdb

* rookie mistake

vendor/github.com/prometheus/tsdb/fileutil/flock.go

@@ -0,0 +1,41 @@
+// Copyright 2016 The Prometheus 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 fileutil
+
+import (
+	"os"
+	"path/filepath"
+)
+
+// Releaser provides the Release method to release a file lock.
+type Releaser interface {
+	Release() error
+}
+
+// Flock locks the file with the provided name. If the file does not exist, it is
+// created. The returned Releaser is used to release the lock. existed is true
+// if the file to lock already existed. A non-nil error is returned if the
+// locking has failed. Neither this function nor the returned Releaser is
+// goroutine-safe.
+func Flock(fileName string) (r Releaser, existed bool, err error) {
+	if err = os.MkdirAll(filepath.Dir(fileName), 0755); err != nil {
+		return nil, false, err
+	}
+
+	_, err = os.Stat(fileName)
+	existed = err == nil
+
+	r, err = newLock(fileName)
+	return r, existed, err
+}