Decouple shared functions between controllers (#8829)

* Decouple shared functions between controllers

* Apply suggestions from code review

Co-authored-by: Jintao Zhang <tao12345666333@163.com>

* Fix package names and fmt

Co-authored-by: Jintao Zhang <tao12345666333@163.com>

pkg/util/process/sigterm.go

@@ -0,0 +1,49 @@
+/*
+Copyright 2022 The Kubernetes 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 process
+
+import (
+	"os"
+	"os/signal"
+	"syscall"
+	"time"
+
+	klog "k8s.io/klog/v2"
+)
+
+type exiter func(code int)
+
+// HandleSigterm receives a ProcessController interface and deals with
+// the graceful shutdown
+func HandleSigterm(ngx ProcessController, delay int, exit exiter) {
+	signalChan := make(chan os.Signal, 1)
+	signal.Notify(signalChan, syscall.SIGTERM)
+	<-signalChan
+	klog.InfoS("Received SIGTERM, shutting down")
+
+	exitCode := 0
+	if err := ngx.Stop(); err != nil {
+		klog.Warningf("Error during shutdown: %v", err)
+		exitCode = 1
+	}
+
+	klog.Infof("Handled quit, delaying controller exit for %d seconds", delay)
+	time.Sleep(time.Duration(delay) * time.Second)
+
+	klog.InfoS("Exiting", "code", exitCode)
+	exit(exitCode)
+}