Move apiserver-reporting logic into k8s_exporter.

Added CLI option "enable-k8s-exporter" (default to true). Users can use
this option to enable/disable exporting to Kubernetes control plane.

This commit also removes all the apiserver-specific logic from package
problemdetector.

Future exporters (e.g. to local journald, Prometheus, other control
planes) should implement types.Exporter interface.

pkg/problemdetector/problem_detector.go

@@ -18,43 +18,33 @@ package problemdetector
 
 import (
 	"fmt"
-	"net/http"
 
 	"github.com/golang/glog"
 
-	"k8s.io/apimachinery/pkg/util/clock"
-
-	"k8s.io/node-problem-detector/pkg/condition"
-	"k8s.io/node-problem-detector/pkg/problemclient"
 	"k8s.io/node-problem-detector/pkg/types"
-	"k8s.io/node-problem-detector/pkg/util"
 )
 
 // ProblemDetector collects statuses from all problem daemons and update the node condition and send node event.
 type ProblemDetector interface {
 	Run() error
-	RegisterHTTPHandlers()
 }
 
 type problemDetector struct {
-	client           problemclient.Client
-	conditionManager condition.ConditionManager
-	monitors         map[string]types.Monitor
+	monitors  map[string]types.Monitor
+	exporters []types.Exporter
 }
 
 // NewProblemDetector creates the problem detector. Currently we just directly passed in the problem daemons, but
 // in the future we may want to let the problem daemons register themselves.
-func NewProblemDetector(monitors map[string]types.Monitor, client problemclient.Client) ProblemDetector {
+func NewProblemDetector(monitors map[string]types.Monitor, exporters []types.Exporter) ProblemDetector {
 	return &problemDetector{
-		client:           client,
-		conditionManager: condition.NewConditionManager(client, clock.RealClock{}),
-		monitors:         monitors,
+		monitors:  monitors,
+		exporters: exporters,
 	}
 }
 
 // Run starts the problem detector.
 func (p *problemDetector) Run() error {
-	p.conditionManager.Start()
 	// Start the log monitors one by one.
 	var chans []<-chan *types.Status
 	for cfg, m := range p.monitors {
@@ -75,24 +65,13 @@ func (p *problemDetector) Run() error {
 	for {
 		select {
 		case status := <-ch:
-			for _, event := range status.Events {
-				p.client.Eventf(util.ConvertToAPIEventType(event.Severity), status.Source, event.Reason, event.Message)
-			}
-			for _, cdt := range status.Conditions {
-				p.conditionManager.UpdateCondition(cdt)
+			for _, exporter := range p.exporters {
+				exporter.ExportProblems(status)
 			}
 		}
 	}
 }
 
-// RegisterHTTPHandlers registers http handlers of node problem detector.
-func (p *problemDetector) RegisterHTTPHandlers() {
-	// Add the handler to serve condition http request.
-	http.HandleFunc("/conditions", func(w http.ResponseWriter, r *http.Request) {
-		util.ReturnHTTPJson(w, p.conditionManager.GetConditions())
-	})
-}
-
 func groupChannel(chans []<-chan *types.Status) <-chan *types.Status {
 	statuses := make(chan *types.Status)
 	for _, ch := range chans {