Print message if metrics are not yet available.

pkg/kubectl/cmd/top_node.go

@@ -107,11 +107,7 @@ func (o *TopNodeOptions) Validate() error {
 }
 
 func (o TopNodeOptions) RunTopNode() error {
-	metrics, err := o.Client.GetNodeMetrics(o.ResourceName, o.Selector)
-	if err != nil {
-		return err
-	}
-
+	var err error
 	selector := labels.Everything()
 	if len(o.Selector) > 0 {
 		selector, err = labels.Parse(o.Selector)
@@ -119,6 +115,11 @@ func (o TopNodeOptions) RunTopNode() error {
 			return err
 		}
 	}
+	metrics, err := o.Client.GetNodeMetrics(o.ResourceName, selector)
+	if err != nil {
+		return err
+	}
+
 	var nodes []api.Node
 	if len(o.ResourceName) > 0 {
 		node, err := o.Client.Nodes().Get(o.ResourceName)

pkg/kubectl/cmd/top_pod.go

@@ -18,31 +18,40 @@ package cmd
 
 import (
 	"errors"
+	"fmt"
 	"io"
+	"time"
 
+	"k8s.io/kubernetes/pkg/api"
 	cmdutil "k8s.io/kubernetes/pkg/kubectl/cmd/util"
 	"k8s.io/kubernetes/pkg/kubectl/metricsutil"
+	"k8s.io/kubernetes/pkg/labels"
 
+	"github.com/golang/glog"
 	"github.com/renstrom/dedent"
 	"github.com/spf13/cobra"
 )
 
-// TopPodOptions contains all the options for running the top-pod cli command.
 type TopPodOptions struct {
 	ResourceName    string
+	Namespace       string
+	Selector        string
 	AllNamespaces   bool
 	PrintContainers bool
-	Selector        string
-	Namespace       string
 	Client          *metricsutil.HeapsterMetricsClient
 	Printer         *metricsutil.TopCmdPrinter
 }
 
+const metricsCreationDelay = 2 * time.Minute
+
 var (
 	topPodLong = dedent.Dedent(`
 		Display Resource (CPU/Memory/Storage) usage of pods.
 
-		The 'top pod' command allows you to see the resource consumption of pods.`)
+		The 'top pod' command allows you to see the resource consumption of pods.
+
+		Due to the metrics pipeline delay, they may be unavailable for a few minutes
+		since pod creation.`)
 
 	topPodExample = dedent.Dedent(`
 		  # Show metrics for all pods in the default namespace
@@ -82,7 +91,6 @@ func NewCmdTopPod(f *cmdutil.Factory, out io.Writer) *cobra.Command {
 	return cmd
 }
 
-// Complete completes all the required options for top.
 func (o *TopPodOptions) Complete(f *cmdutil.Factory, cmd *cobra.Command, args []string, out io.Writer) error {
 	var err error
 	if len(args) == 1 {
@@ -111,11 +119,68 @@ func (o *TopPodOptions) Validate() error {
 	return nil
 }
 
-// RunTop implements all the necessary functionality for top.
 func (o TopPodOptions) RunTopPod() error {
-	metrics, err := o.Client.GetPodMetrics(o.Namespace, o.ResourceName, o.AllNamespaces, o.Selector)
+	var err error
+	selector := labels.Everything()
+	if len(o.Selector) > 0 {
+		selector, err = labels.Parse(o.Selector)
+		if err != nil {
+			return err
+		}
+	}
+	metrics, err := o.Client.GetPodMetrics(o.Namespace, o.ResourceName, o.AllNamespaces, selector)
+	// TODO: Refactor this once Heapster becomes the API server.
+	// First we check why no metrics have been received.
+	if len(metrics) == 0 {
+		// If the API server query is successful but all the pods are newly created,
+		// the metrics are probably not ready yet, so we return the error here in the first place.
+		e := verifyEmptyMetrics(o, selector)
+		if e != nil {
+			return e
+		}
+	}
 	if err != nil {
 		return err
 	}
 	return o.Printer.PrintPodMetrics(metrics, o.PrintContainers, o.AllNamespaces)
 }
+
+func verifyEmptyMetrics(o TopPodOptions, selector labels.Selector) error {
+	if len(o.ResourceName) > 0 {
+		pod, err := o.Client.Pods(o.Namespace).Get(o.ResourceName)
+		if err != nil {
+			return err
+		}
+		if err := checkPodAge(pod); err != nil {
+			return err
+		}
+	} else {
+		pods, err := o.Client.Pods(o.Namespace).List(api.ListOptions{
+			LabelSelector: selector,
+		})
+		if err != nil {
+			return err
+		}
+		if len(pods.Items) == 0 {
+			return nil
+		}
+		for _, pod := range pods.Items {
+			if err := checkPodAge(&pod); err != nil {
+				return err
+			}
+		}
+	}
+	return errors.New("metrics not available yet")
+}
+
+func checkPodAge(pod *api.Pod) error {
+	age := time.Since(pod.CreationTimestamp.Time)
+	if age > metricsCreationDelay {
+		message := fmt.Sprintf("Metrics not available for pod %s/%s, age: %s", pod.Namespace, pod.Name, age.String())
+		glog.Warningf(message)
+		return errors.New(message)
+	} else {
+		glog.V(2).Infof("Metrics not yet available for pod %s/%s, age: %s", pod.Namespace, pod.Name, age.String())
+		return nil
+	}
+}

pkg/kubectl/metricsutil/metrics_client.go

@@ -26,6 +26,7 @@ import (
 	"k8s.io/kubernetes/pkg/api/unversioned"
 	"k8s.io/kubernetes/pkg/api/validation"
 	client "k8s.io/kubernetes/pkg/client/unversioned"
+	"k8s.io/kubernetes/pkg/labels"
 )
 
 const (
@@ -96,8 +97,8 @@ func nodeMetricsUrl(name string) (string, error) {
 	return fmt.Sprintf("%s/nodes/%s", metricsRoot, name), nil
 }
 
-func (cli *HeapsterMetricsClient) GetNodeMetrics(nodeName string, selector string) ([]metrics_api.NodeMetrics, error) {
-	params := map[string]string{"labelSelector": selector}
+func (cli *HeapsterMetricsClient) GetNodeMetrics(nodeName string, selector labels.Selector) ([]metrics_api.NodeMetrics, error) {
+	params := map[string]string{"labelSelector": selector.String()}
 	path, err := nodeMetricsUrl(nodeName)
 	if err != nil {
 		return []metrics_api.NodeMetrics{}, err
@@ -125,7 +126,7 @@ func (cli *HeapsterMetricsClient) GetNodeMetrics(nodeName string, selector strin
 	return metrics, nil
 }
 
-func (cli *HeapsterMetricsClient) GetPodMetrics(namespace string, podName string, allNamespaces bool, selector string) ([]metrics_api.PodMetrics, error) {
+func (cli *HeapsterMetricsClient) GetPodMetrics(namespace string, podName string, allNamespaces bool, selector labels.Selector) ([]metrics_api.PodMetrics, error) {
 	if allNamespaces {
 		namespace = api.NamespaceAll
 	}
@@ -133,7 +134,8 @@ func (cli *HeapsterMetricsClient) GetPodMetrics(namespace string, podName string
 	if err != nil {
 		return []metrics_api.PodMetrics{}, err
 	}
-	params := map[string]string{"labelSelector": selector}
+
+	params := map[string]string{"labelSelector": selector.String()}
 	allMetrics := make([]metrics_api.PodMetrics, 0)
 
 	resultRaw, err := GetHeapsterMetrics(cli, path, params)