util: add health-checker for periodic filesystem checks

Signed-off-by: Niels de Vos <ndevos@ibm.com>

internal/health-checker/statchecker.go

@@ -0,0 +1,70 @@
+/*
+Copyright 2023 ceph-csi 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 healthchecker
+
+import (
+	"os"
+	"time"
+)
+
+type statChecker struct {
+	checker
+
+	// dirname points to the directory that is used for checking.
+	dirname string
+}
+
+func newStatChecker(dir string) ConditionChecker {
+	sc := &statChecker{
+		dirname: dir,
+	}
+	sc.initDefaults()
+
+	sc.checker.runChecker = func() {
+		sc.isRunning = true
+
+		ticker := time.NewTicker(sc.interval)
+		defer ticker.Stop()
+
+		for {
+			select {
+			case <-sc.commands: // STOP command received
+				sc.isRunning = false
+
+				return
+			case now := <-ticker.C:
+				_, err := os.Stat(sc.dirname)
+				if err != nil {
+					sc.mutex.Lock()
+					sc.healthy = false
+					sc.err = err
+					sc.mutex.Unlock()
+
+					continue
+				}
+
+				sc.mutex.Lock()
+				sc.healthy = true
+				sc.err = nil
+				sc.lastUpdate = now
+				sc.mutex.Unlock()
+			}
+		}
+	}
+
+	return sc
+}