Add metrics to monitor the kubelet http server

Signed-off-by: Haiyan Meng <haiyanmeng@google.com>

pkg/kubelet/server/server_test.go

@@ -1666,3 +1666,24 @@ func TestDebuggingDisabledHandlers(t *testing.T) {
 	assert.Equal(t, http.StatusOK, resp.StatusCode)
 
 }
+
+func TestTrimURLPath(t *testing.T) {
+	tests := []struct {
+		path, expected string
+	}{
+		{"", ""},
+		{"//", ""},
+		{"/pods", "pods"},
+		{"pods", "pods"},
+		{"pods/", "pods"},
+		{"good/", "good"},
+		{"pods/probes", "pods"},
+		{"metrics", "metrics"},
+		{"metrics/resource", "metrics/resource"},
+		{"metrics/hello", "metrics/hello"},
+	}
+
+	for _, test := range tests {
+		assert.Equal(t, test.expected, trimURLPath(test.path), fmt.Sprintf("path is: %s", test.path))
+	}
+}