Limit the logging from kubelet attempting to read its manifest URL.

Without this, it logs an error every 20 seconds if nothing is at the
provided URL.

pkg/kubelet/config/http.go

@@ -37,6 +37,7 @@ type sourceURL struct {
 	nodeName    string
 	updates     chan<- interface{}
 	data        []byte
+	failureLogs int
 }
 
 func NewSourceURL(url string, header http.Header, nodeName string, period time.Duration, updates chan<- interface{}) {
@@ -53,7 +54,19 @@ func NewSourceURL(url string, header http.Header, nodeName string, period time.D
 
 func (s *sourceURL) run() {
 	if err := s.extractFromURL(); err != nil {
-		glog.Errorf("Failed to read URL: %v", err)
+		// Don't log this multiple times per minute. The first few entries should be
+		// enough to get the point across.
+		if s.failureLogs < 3 {
+			glog.Warningf("Failed to read pods from URL: %v", err)
+		} else if s.failureLogs == 3 {
+			glog.Warningf("Failed to read pods from URL. Won't log this message anymore: %v", err)
+		}
+		s.failureLogs++
+	} else {
+		if s.failureLogs > 0 {
+			glog.Info("Successfully read pods from URL.")
+			s.failureLogs = 0
+		}
 	}
 }
 

pkg/kubelet/config/http_test.go

@@ -44,7 +44,7 @@ func TestURLErrorNotExistNoUpdate(t *testing.T) {
 
 func TestExtractFromHttpBadness(t *testing.T) {
 	ch := make(chan interface{}, 1)
-	c := sourceURL{"http://localhost:49575/_not_found_", http.Header{}, "other", ch, nil}
+	c := sourceURL{"http://localhost:49575/_not_found_", http.Header{}, "other", ch, nil, 0}
 	if err := c.extractFromURL(); err == nil {
 		t.Errorf("Expected error")
 	}
@@ -113,7 +113,7 @@ func TestExtractInvalidPods(t *testing.T) {
 		testServer := httptest.NewServer(&fakeHandler)
 		defer testServer.Close()
 		ch := make(chan interface{}, 1)
-		c := sourceURL{testServer.URL, http.Header{}, "localhost", ch, nil}
+		c := sourceURL{testServer.URL, http.Header{}, "localhost", ch, nil, 0}
 		if err := c.extractFromURL(); err == nil {
 			t.Errorf("%s: Expected error", testCase.desc)
 		}
@@ -260,7 +260,7 @@ func TestExtractPodsFromHTTP(t *testing.T) {
 		testServer := httptest.NewServer(&fakeHandler)
 		defer testServer.Close()
 		ch := make(chan interface{}, 1)
-		c := sourceURL{testServer.URL, http.Header{}, hostname, ch, nil}
+		c := sourceURL{testServer.URL, http.Header{}, hostname, ch, nil, 0}
 		if err := c.extractFromURL(); err != nil {
 			t.Errorf("%s: Unexpected error: %v", testCase.desc, err)
 			continue
@@ -307,7 +307,7 @@ func TestURLWithHeader(t *testing.T) {
 	ch := make(chan interface{}, 1)
 	header := make(http.Header)
 	header.Set("Metadata-Flavor", "Google")
-	c := sourceURL{testServer.URL, header, "localhost", ch, nil}
+	c := sourceURL{testServer.URL, header, "localhost", ch, nil, 0}
 	if err := c.extractFromURL(); err != nil {
 		t.Fatalf("Unexpected error extracting from URL: %v", err)
 	}