Enable NPD to run as a Windows Service.

Author: jeremyje

.gitignore

@@ -4,3 +4,4 @@
 ci.env
 pr.env
 junit*.xml
+debug.test

README.md

@@ -229,6 +229,11 @@ make test
 
 # Run with containerd log monitoring enabled. (Assumes containerd is installed.)
 %CD%\bin\windows_amd64\node-problem-detector.exe --logtostderr --enable-k8s-exporter=false --config.system-log-monitor=%CD%\config\windows-containerd-monitor-filelog.json
+
+# Configure NPD to run as a Windows Service
+sc.exe create NodeProblemDetector binpath= "%CD%\node-problem-detector.exe [FLAGS]" start= demand 
+sc.exe failure NodeProblemDetector reset= 0 actions= restart/10000
+sc.exe start NodeProblemDetector
 ```
 
 ## Try It Out

cmd/nodeproblemdetector/node_problem_detector.go

@@ -17,10 +17,7 @@ limitations under the License.
 package main
 
 import (
-	"os"
-
 	"github.com/golang/glog"
-	"github.com/spf13/pflag"
 
 	_ "k8s.io/node-problem-detector/cmd/nodeproblemdetector/exporterplugins"
 	_ "k8s.io/node-problem-detector/cmd/nodeproblemdetector/problemdaemonplugins"
@@ -34,15 +31,19 @@ import (
 	"k8s.io/node-problem-detector/pkg/version"
 )
 
-func main() {
-	npdo := options.NewNodeProblemDetectorOptions()
-	npdo.AddFlags(pflag.CommandLine)
+func npdInteractive(npdo *options.NodeProblemDetectorOptions) {
+	termCh := make(chan error, 1)
+	defer close(termCh)
 
-	pflag.Parse()
+	if err := npdMain(npdo, termCh); err != nil {
+		glog.Fatalf("Problem detector failed with error: %v", err)
+	}
+}
 
+func npdMain(npdo *options.NodeProblemDetectorOptions, termCh <-chan error) error {
 	if npdo.PrintVersion {
 		version.PrintVersion()
-		os.Exit(0)
+		return nil
 	}
 
 	npdo.SetNodeNameOrDie()
@@ -78,7 +79,5 @@ func main() {
 
 	// Initialize NPD core.
 	p := problemdetector.NewProblemDetector(problemDaemons, npdExporters)
-	if err := p.Run(); err != nil {
-		glog.Fatalf("Problem detector failed with error: %v", err)
-	}
+	return p.Run(termCh)
 }

cmd/nodeproblemdetector/node_problem_detector_linux.go

@@ -0,0 +1,30 @@
+/*
+Copyright 2021 The Kubernetes Authors All rights reserved.
+
+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 main
+
+import (
+	"github.com/spf13/pflag"
+	"k8s.io/node-problem-detector/cmd/options"
+)
+
+func main() {
+	npdo := options.NewNodeProblemDetectorOptions()
+	npdo.AddFlags(pflag.CommandLine)
+
+	pflag.Parse()
+	npdInteractive(npdo)
+}

cmd/nodeproblemdetector/node_problem_detector_test.go

@@ -0,0 +1,133 @@
+/*
+Copyright 2021 The Kubernetes Authors All rights reserved.
+
+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 main
+
+import (
+	"errors"
+	"fmt"
+	"io/ioutil"
+	"os"
+	"strings"
+	"testing"
+
+	_ "k8s.io/node-problem-detector/cmd/nodeproblemdetector/exporterplugins"
+	_ "k8s.io/node-problem-detector/cmd/nodeproblemdetector/problemdaemonplugins"
+	"k8s.io/node-problem-detector/cmd/options"
+	"k8s.io/node-problem-detector/pkg/exporters"
+	"k8s.io/node-problem-detector/pkg/types"
+)
+
+const (
+	fakeConfigFilePattern = `
+{
+	"plugin": "filelog",
+	"pluginConfig": {
+		"timestamp": "^time=\"(\\S*)\"",
+		"message": "msg=\"([^\n]*)\"",
+		"timestampFormat": "2006-01-02T15:04:05.999999999-07:00"
+	},
+	"logPath": "%s",
+	"lookback": "5m",
+	"bufferSize": 10,
+	"source": "containerd",
+	"conditions": [],
+	"rules": [
+		{
+			"type": "temporary",
+			"reason": "MissingPigz",
+			"pattern": "unpigz not found.*"
+		},
+		{
+			"type": "temporary",
+			"reason": "IncompatibleContainer",
+			"pattern": ".*CreateComputeSystem.*"
+		}
+	]
+}
+	`
+)
+
+func init() {
+	exporters.Register("nil", types.ExporterHandler{
+		CreateExporterOrDie: func(types.CommandLineOptions) types.Exporter {
+			return &nullExporter{}
+		},
+	})
+}
+
+type nullExporter struct {
+}
+
+func (ne *nullExporter) ExportProblems(*types.Status) {
+}
+
+func TestNPDMain(t *testing.T) {
+	npdo, cleanup := setupNPD(t)
+	defer cleanup()
+
+	termCh := make(chan error, 2)
+	termCh <- errors.New("close")
+	defer close(termCh)
+
+	if err := npdMain(npdo, termCh); err != nil {
+		t.Errorf("termination signal should not return error got, %v", err)
+	}
+}
+
+func writeTempFile(t *testing.T, ext string, contents string) (string, error) {
+	f, err := ioutil.TempFile("", "*."+ext)
+	if err != nil {
+		return "", fmt.Errorf("cannot create temp file, %v", err)
+	}
+
+	fileName := f.Name()
+
+	if err := ioutil.WriteFile(fileName, []byte(contents), 0644); err != nil {
+		os.Remove(fileName)
+		return "", fmt.Errorf("cannot write config to temp file %s, %v", fileName, err)
+	}
+
+	return fileName, nil
+}
+
+func setupNPD(t *testing.T) (*options.NodeProblemDetectorOptions, func()) {
+	fakeLogFileName, err := writeTempFile(t, "log", "")
+	if err != nil {
+		os.Remove(fakeLogFileName)
+		t.Fatalf("cannot create temp config file, %v", err)
+	}
+
+	fakeConfigFileContents := fmt.Sprintf(fakeConfigFilePattern, strings.ReplaceAll(fakeLogFileName, "\\", "\\\\"))
+
+	fakeConfigFileName, err := writeTempFile(t, "json", fakeConfigFileContents)
+	if err != nil {
+		os.Remove(fakeLogFileName)
+		os.Remove(fakeConfigFileName)
+		t.Fatalf("cannot create temp config file, %v", err)
+	}
+
+	return &options.NodeProblemDetectorOptions{
+			MonitorConfigPaths: map[types.ProblemDaemonType]*[]string{
+				"system-log-monitor": {
+					fakeConfigFileName,
+				},
+			},
+		}, func() {
+			os.Remove(fakeLogFileName)
+			os.Remove(fakeConfigFileName)
+		}
+}