crictl: add metrics{,p} command

which are aliases to each other
currently json and yaml output are supported

Signed-off-by: Peter Hunt <pehunt@redhat.com>

cmd/crictl/main.go

@@ -175,6 +175,7 @@ func main() {
 		configCommand,
 		statsCommand,
 		podStatsCommand,
+		podMetricsCommand,
 		completionCommand,
 		checkpointContainerCommand,
 		runtimeConfigCommand,

cmd/crictl/pod_metrics.go

@@ -0,0 +1,155 @@
+/*
+Copyright 2023 The Kubernetes Authors.
+
+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 main
+
+import (
+	"fmt"
+	"time"
+
+	"github.com/sirupsen/logrus"
+	"github.com/urfave/cli/v2"
+	"golang.org/x/net/context"
+	cri "k8s.io/cri-api/pkg/apis"
+	pb "k8s.io/cri-api/pkg/apis/runtime/v1"
+)
+
+type podMetricsOptions struct {
+	// output format
+	output string
+
+	// live watch
+	watch bool
+}
+
+var podMetricsCommand = &cli.Command{
+	Name:                   "metricsp",
+	Aliases:                []string{"metrics"},
+	Usage:                  "List pod resource usage statistics",
+	UseShortOptionHandling: true,
+	ArgsUsage:              "[ID]",
+	Flags: []cli.Flag{
+		&cli.StringFlag{
+			Name:    "output",
+			Aliases: []string{"o"},
+			Usage:   "Output format, One of: json|yaml",
+		},
+		&cli.BoolFlag{
+			Name:    "watch",
+			Aliases: []string{"w"},
+			Usage:   "Watch pod metrics",
+		},
+	},
+	Action: func(c *cli.Context) error {
+		if c.NArg() > 0 {
+			return cli.ShowSubcommandHelp(c)
+		}
+
+		client, err := getRuntimeService(c, 0)
+		if err != nil {
+			return fmt.Errorf("get runtime service: %w", err)
+		}
+
+		opts := podMetricsOptions{
+			output: c.String("output"),
+			watch:  c.Bool("watch"),
+		}
+
+		switch opts.output {
+		case "json", "yaml", "":
+		default:
+			return cli.ShowSubcommandHelp(c)
+		}
+
+		if err := podMetrics(c.Context, client, opts); err != nil {
+			return fmt.Errorf("get pod metrics: %w", err)
+		}
+
+		return nil
+	},
+}
+
+func podMetrics(
+	c context.Context,
+	client cri.RuntimeService,
+	opts podMetricsOptions,
+) error {
+	if !opts.watch {
+		if err := displayPodMetrics(c, client, opts); err != nil {
+			return fmt.Errorf("display pod metrics: %w", err)
+		}
+
+		return nil
+	}
+
+	displayErrCh := make(chan error, 1)
+	ticker := time.NewTicker(500 * time.Millisecond)
+	defer ticker.Stop()
+
+	watchCtx, cancelFn := context.WithCancel(context.Background())
+	defer cancelFn()
+
+	// Put the displayPodMetrics in another goroutine, because it might be
+	// time consuming with lots of pods and we want to cancel it
+	// ASAP when user hit CtrlC
+	go func() {
+		for range ticker.C {
+			if err := displayPodMetrics(watchCtx, client, opts); err != nil {
+				displayErrCh <- err
+				break
+			}
+		}
+	}()
+
+	// listen for CtrlC or error
+	select {
+	case <-SetupInterruptSignalHandler():
+		cancelFn()
+		return nil
+	case err := <-displayErrCh:
+		return err
+	}
+}
+
+func displayPodMetrics(
+	c context.Context,
+	client cri.RuntimeService,
+	opts podMetricsOptions,
+) error {
+	metrics, err := podSandboxMetrics(client)
+	if err != nil {
+		return err
+	}
+
+	response := &pb.ListPodSandboxMetricsResponse{PodMetrics: metrics}
+	switch opts.output {
+	case "json", "":
+		return outputProtobufObjAsJSON(response)
+	case "yaml":
+		return outputProtobufObjAsYAML(response)
+	}
+	return nil
+}
+
+func podSandboxMetrics(client cri.RuntimeService) ([]*pb.PodSandboxMetrics, error) {
+	metrics, err := client.ListPodSandboxMetrics(context.TODO())
+	if err != nil {
+		return nil, fmt.Errorf("list pod sandbox metrics: %w", err)
+	}
+	logrus.Debugf("PodMetrics: %v", metrics)
+
+	return metrics, nil
+}