add custom problem detector plugin

pkg/custompluginmonitor/custom_plugin_monitor.go

@@ -0,0 +1,167 @@
+/*
+Copyright 2017 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 custompluginmonitor
+
+import (
+	"encoding/json"
+	"io/ioutil"
+	"time"
+
+	"github.com/golang/glog"
+
+	"k8s.io/node-problem-detector/pkg/custompluginmonitor/plugin"
+	cpmtypes "k8s.io/node-problem-detector/pkg/custompluginmonitor/types"
+	"k8s.io/node-problem-detector/pkg/types"
+	"k8s.io/node-problem-detector/pkg/util/tomb"
+)
+
+type customPluginMonitor struct {
+	config     cpmtypes.CustomPluginConfig
+	conditions []types.Condition
+	plugin     *plugin.Plugin
+	resultChan <-chan cpmtypes.Result
+	statusChan chan *types.Status
+	tomb       *tomb.Tomb
+}
+
+// NewCustomPluginMonitorOrDie create a new customPluginMonitor, panic if error occurs.
+func NewCustomPluginMonitorOrDie(configPath string) types.Monitor {
+	c := &customPluginMonitor{
+		tomb: tomb.NewTomb(),
+	}
+	f, err := ioutil.ReadFile(configPath)
+	if err != nil {
+		glog.Fatalf("Failed to read configuration file %q: %v", configPath, err)
+	}
+	err = json.Unmarshal(f, &c.config)
+	if err != nil {
+		glog.Fatalf("Failed to unmarshal configuration file %q: %v", configPath, err)
+	}
+	// Apply configurations
+	err = (&c.config).ApplyConfiguration()
+	if err != nil {
+		glog.Fatalf("Failed to apply configuration for %q: %v", configPath, err)
+	}
+
+	// Validate configurations
+	err = c.config.Validate()
+	if err != nil {
+		glog.Fatalf("Failed to validate custom plugin config %+v: %v", c.config, err)
+	}
+
+	glog.Infof("Finish parsing custom plugin monitor config file: %+v", c.config)
+
+	c.plugin = plugin.NewPlugin(c.config)
+	// A 1000 size channel should be big enough.
+	c.statusChan = make(chan *types.Status, 1000)
+	return c
+}
+
+func (c *customPluginMonitor) Start() (<-chan *types.Status, error) {
+	glog.Info("Start custom plugin monitor")
+	go c.plugin.Run()
+	go c.monitorLoop()
+	return c.statusChan, nil
+}
+
+func (c *customPluginMonitor) Stop() {
+	glog.Info("Stop custom plugin monitor")
+	c.tomb.Stop()
+}
+
+// monitorLoop is the main loop of log monitor.
+func (c *customPluginMonitor) monitorLoop() {
+	c.initializeStatus()
+
+	resultChan := c.plugin.GetResultChan()
+
+	for {
+		select {
+		case result := <-resultChan:
+			glog.V(3).Infof("Receive new plugin result: %+v", result)
+			status := c.generateStatus(result)
+			glog.Infof("New status generated: %+v", status)
+			c.statusChan <- status
+		case <-c.tomb.Stopping():
+			c.plugin.Stop()
+			glog.Infof("Custom plugin monitor stopped")
+			c.tomb.Done()
+			break
+		}
+	}
+}
+
+// generateStatus generates status from the plugin check result.
+func (c *customPluginMonitor) generateStatus(result cpmtypes.Result) *types.Status {
+	timestamp := time.Now()
+	var events []types.Event
+	if result.Rule.Type == types.Temp {
+		// For temporary error only generate event when exit status is above warning
+		if result.ExitStatus >= cpmtypes.NonOK {
+			events = append(events, types.Event{
+				Severity:  types.Warn,
+				Timestamp: timestamp,
+				Reason:    result.Rule.Reason,
+				Message:   result.Message,
+			})
+		}
+	} else {
+		// For permanent error changes the condition
+		for i := range c.conditions {
+			condition := &c.conditions[i]
+			if condition.Type == result.Rule.Condition {
+				status := result.ExitStatus >= cpmtypes.NonOK
+				if condition.Status != status || condition.Reason != result.Rule.Reason {
+					condition.Transition = timestamp
+					condition.Message = result.Message
+				}
+				condition.Status = status
+				condition.Reason = result.Rule.Reason
+				break
+			}
+		}
+	}
+	return &types.Status{
+		Source: c.config.Source,
+		// TODO(random-liu): Aggregate events and conditions and then do periodically report.
+		Events:     events,
+		Conditions: c.conditions,
+	}
+}
+
+// initializeStatus initializes the internal condition and also reports it to the node problem detector.
+func (c *customPluginMonitor) initializeStatus() {
+	// Initialize the default node conditions
+	c.conditions = initialConditions(c.config.DefaultConditions)
+	glog.Infof("Initialize condition generated: %+v", c.conditions)
+	// Update the initial status
+	c.statusChan <- &types.Status{
+		Source:     c.config.Source,
+		Conditions: c.conditions,
+	}
+}
+
+func initialConditions(defaults []types.Condition) []types.Condition {
+	conditions := make([]types.Condition, len(defaults))
+	copy(conditions, defaults)
+	for i := range conditions {
+		// TODO(random-liu): Validate default conditions
+		conditions[i].Status = false
+		conditions[i].Transition = time.Now()
+	}
+	return conditions
+}