podmanv2: implement pod top

Implement `podman pod top` for podmanV2.

Signed-off-by: Valentin Rothberg <rothberg@redhat.com>

cmd/podmanV2/pods/top.go

@@ -0,0 +1,90 @@
+package pods
+
+import (
+	"context"
+	"fmt"
+	"os"
+	"strings"
+	"text/tabwriter"
+
+	"github.com/containers/libpod/cmd/podmanV2/registry"
+	"github.com/containers/libpod/pkg/domain/entities"
+	"github.com/containers/psgo"
+	"github.com/pkg/errors"
+	"github.com/spf13/cobra"
+)
+
+var (
+	topDescription = fmt.Sprintf(`Specify format descriptors to alter the output.
+
+	You may run "podman pod top -l pid pcpu seccomp" to print the process ID, the CPU percentage and the seccomp mode of each process of the latest pod.
+  Format Descriptors:
+    %s`, strings.Join(psgo.ListDescriptors(), ","))
+
+	topOptions = entities.PodTopOptions{}
+
+	topCommand = &cobra.Command{
+		Use:               "top [flags] POD [FORMAT-DESCRIPTORS|ARGS]",
+		Short:             "Display the running processes in a pod",
+		Long:              topDescription,
+		PersistentPreRunE: preRunE,
+		RunE:              top,
+		Args:              cobra.ArbitraryArgs,
+		Example: `podman pod top podID
+podman pod top --latest
+podman pod top podID pid seccomp args %C
+podman pod top podID -eo user,pid,comm`,
+	}
+)
+
+func init() {
+	registry.Commands = append(registry.Commands, registry.CliCommand{
+		Mode:    []entities.EngineMode{entities.ABIMode, entities.TunnelMode},
+		Command: topCommand,
+		Parent:  podCmd,
+	})
+
+	topCommand.SetHelpTemplate(registry.HelpTemplate())
+	topCommand.SetUsageTemplate(registry.UsageTemplate())
+
+	flags := topCommand.Flags()
+	flags.SetInterspersed(false)
+	flags.BoolVar(&topOptions.ListDescriptors, "list-descriptors", false, "")
+	flags.BoolVarP(&topOptions.Latest, "latest", "l", false, "Act on the latest container podman is aware of")
+
+	_ = flags.MarkHidden("list-descriptors") // meant only for bash completion
+	if registry.IsRemote() {
+		_ = flags.MarkHidden("latest")
+	}
+}
+
+func top(cmd *cobra.Command, args []string) error {
+	if topOptions.ListDescriptors {
+		fmt.Println(strings.Join(psgo.ListDescriptors(), "\n"))
+		return nil
+	}
+
+	if len(args) < 1 && !topOptions.Latest {
+		return errors.Errorf("you must provide the name or id of a running pod")
+	}
+
+	if topOptions.Latest {
+		topOptions.Descriptors = args
+	} else {
+		topOptions.NameOrID = args[0]
+		topOptions.Descriptors = args[1:]
+	}
+
+	topResponse, err := registry.ContainerEngine().PodTop(context.Background(), topOptions)
+	if err != nil {
+		return err
+	}
+
+	w := tabwriter.NewWriter(os.Stdout, 5, 1, 3, ' ', 0)
+	for _, proc := range topResponse.Value {
+		if _, err := fmt.Fprintln(w, proc); err != nil {
+			return err
+		}
+	}
+	return w.Flush()
+}

libpod/pod_top_linux.go

@@ -41,12 +41,23 @@ func (p *Pod) GetPodPidInformation(descriptors []string) ([]string, error) {
 		}
 		c.lock.Unlock()
 	}
+
+	// Also support comma-separated input.
+	psgoDescriptors := []string{}
+	for _, d := range descriptors {
+		for _, s := range strings.Split(d, ",") {
+			if s != "" {
+				psgoDescriptors = append(psgoDescriptors, s)
+			}
+		}
+	}
+
 	// TODO: psgo returns a [][]string to give users the ability to apply
 	//       filters on the data.  We need to change the API here and the
 	//       varlink API to return a [][]string if we want to make use of
 	//       filtering.
 	opts := psgo.JoinNamespaceOpts{FillMappings: rootless.IsRootless()}
-	output, err := psgo.JoinNamespaceAndProcessInfoByPidsWithOptions(pids, descriptors, &opts)
+	output, err := psgo.JoinNamespaceAndProcessInfoByPidsWithOptions(pids, psgoDescriptors, &opts)
 	if err != nil {
 		return nil, err
 	}

pkg/bindings/pods/pods.go

@@ -8,6 +8,7 @@ import (
 	"strings"
 
 	"github.com/containers/libpod/libpod"
+	"github.com/containers/libpod/pkg/api/handlers"
 	"github.com/containers/libpod/pkg/bindings"
 	"github.com/containers/libpod/pkg/domain/entities"
 	"github.com/containers/libpod/pkg/specgen"
@@ -213,9 +214,38 @@ func Stop(ctx context.Context, nameOrID string, timeout *int) (*entities.PodStop
 	return &report, response.Process(&report)
 }
 
-func Top() error {
-	// TODO
-	return bindings.ErrNotImplemented // nolint:typecheck
+// Top gathers statistics about the running processes in a pod. The nameOrID can be a pod name
+// or a partial/full ID.  The descriptors allow for specifying which data to collect from each process.
+func Top(ctx context.Context, nameOrID string, descriptors []string) ([]string, error) {
+	conn, err := bindings.GetClient(ctx)
+	if err != nil {
+		return nil, err
+	}
+	params := url.Values{}
+
+	if len(descriptors) > 0 {
+		// flatten the slice into one string
+		params.Set("ps_args", strings.Join(descriptors, ","))
+	}
+	response, err := conn.DoRequest(nil, http.MethodGet, "/pods/%s/top", params, nameOrID)
+	if err != nil {
+		return nil, err
+	}
+
+	body := handlers.PodTopOKBody{}
+	if err = response.Process(&body); err != nil {
+		return nil, err
+	}
+
+	// handlers.PodTopOKBody{} returns a slice of slices where each cell in the top table is an item.
+	// In libpod land, we're just using a slice with cells being split by tabs, which allows for an idiomatic
+	// usage of the tabwriter.
+	topOutput := []string{strings.Join(body.Titles, "\t")}
+	for _, out := range body.Processes {
+		topOutput = append(topOutput, strings.Join(out, "\t"))
+	}
+
+	return topOutput, err
 }
 
 // Unpause unpauses all paused containers in a Pod.

pkg/bindings/test/containers_test.go

@@ -387,15 +387,15 @@ var _ = Describe("Podman containers ", func() {
 		Expect(err).To(BeNil())
 
 		// By name
-		output, err := containers.Top(bt.conn, name, nil)
+		_, err = containers.Top(bt.conn, name, nil)
 		Expect(err).To(BeNil())
 
 		// By id
-		output, err = containers.Top(bt.conn, cid, nil)
+		_, err = containers.Top(bt.conn, cid, nil)
 		Expect(err).To(BeNil())
 
 		// With descriptors
-		output, err = containers.Top(bt.conn, cid, []string{"user,pid,hpid"})
+		output, err := containers.Top(bt.conn, cid, []string{"user,pid,hpid"})
 		Expect(err).To(BeNil())
 		header := strings.Split(output[0], "\t")
 		for _, d := range []string{"USER", "PID", "HPID"} {

pkg/bindings/test/pods_test.go

@@ -2,6 +2,7 @@ package test_bindings
 
 import (
 	"net/http"
+	"strings"
 	"time"
 
 	"github.com/containers/libpod/libpod/define"
@@ -319,4 +320,33 @@ var _ = Describe("Podman pods", func() {
 		Expect(err).To(BeNil())
 		Expect(exists).To(BeTrue())
 	})
+
+	// Test validates the pod top bindings
+	It("pod top", func() {
+		var name string = "podA"
+
+		bt.Podcreate(&name)
+		_, err := pods.Start(bt.conn, name)
+		Expect(err).To(BeNil())
+
+		// By name
+		_, err = pods.Top(bt.conn, name, nil)
+		Expect(err).To(BeNil())
+
+		// With descriptors
+		output, err := pods.Top(bt.conn, name, []string{"user,pid,hpid"})
+		Expect(err).To(BeNil())
+		header := strings.Split(output[0], "\t")
+		for _, d := range []string{"USER", "PID", "HPID"} {
+			Expect(d).To(BeElementOf(header))
+		}
+
+		// With bogus ID
+		_, err = pods.Top(bt.conn, "IdoNotExist", nil)
+		Expect(err).ToNot(BeNil())
+
+		// With bogus descriptors
+		_, err = pods.Top(bt.conn, name, []string{"Me,Neither"})
+		Expect(err).ToNot(BeNil())
+	})
 })

pkg/domain/entities/engine_container.go

@@ -24,6 +24,7 @@ type ContainerEngine interface {
 	PodStop(ctx context.Context, namesOrIds []string, options PodStopOptions) ([]*PodStopReport, error)
 	PodRm(ctx context.Context, namesOrIds []string, options PodRmOptions) ([]*PodRmReport, error)
 	PodUnpause(ctx context.Context, namesOrIds []string, options PodunpauseOptions) ([]*PodUnpauseReport, error)
+	PodTop(ctx context.Context, options PodTopOptions) (*StringSliceReport, error)
 
 	VolumeCreate(ctx context.Context, opts VolumeCreateOptions) (*IdOrNameResponse, error)
 	VolumeInspect(ctx context.Context, namesOrIds []string, opts VolumeInspectOptions) ([]*VolumeInspectReport, error)

pkg/domain/entities/pods.go

@@ -141,3 +141,13 @@ func (p PodCreateOptions) ToPodSpecGen(s *specgen.PodSpecGenerator) {
 	// Cgroup
 	s.CgroupParent = p.CGroupParent
 }
+
+type PodTopOptions struct {
+	// CLI flags.
+	ListDescriptors bool
+	Latest          bool
+
+	// Options for the API.
+	Descriptors []string
+	NameOrID    string
+}

pkg/domain/infra/abi/pods.go

@@ -250,3 +250,25 @@ func (ic *ContainerEngine) PodCreate(ctx context.Context, opts entities.PodCreat
 	}
 	return &entities.PodCreateReport{Id: pod.ID()}, nil
 }
+
+func (ic *ContainerEngine) PodTop(ctx context.Context, options entities.PodTopOptions) (*entities.StringSliceReport, error) {
+	var (
+		pod *libpod.Pod
+		err error
+	)
+
+	// Look up the pod.
+	if options.Latest {
+		pod, err = ic.Libpod.GetLatestPod()
+	} else {
+		pod, err = ic.Libpod.LookupPod(options.NameOrID)
+	}
+	if err != nil {
+		return nil, errors.Wrap(err, "unable to lookup requested container")
+	}
+
+	// Run Top.
+	report := &entities.StringSliceReport{}
+	report.Value, err = pod.GetPodPidInformation(options.Descriptors)
+	return report, err
+}

pkg/domain/infra/tunnel/pods.go

@@ -6,6 +6,7 @@ import (
 	"github.com/containers/libpod/pkg/bindings/pods"
 	"github.com/containers/libpod/pkg/domain/entities"
 	"github.com/containers/libpod/pkg/specgen"
+	"github.com/pkg/errors"
 )
 
 func (ic *ContainerEngine) PodExists(ctx context.Context, nameOrId string) (*entities.BoolReport, error) {
@@ -177,3 +178,18 @@ func (ic *ContainerEngine) PodCreate(ctx context.Context, opts entities.PodCreat
 	opts.ToPodSpecGen(podSpec)
 	return pods.CreatePodFromSpec(ic.ClientCxt, podSpec)
 }
+
+func (ic *ContainerEngine) PodTop(ctx context.Context, options entities.PodTopOptions) (*entities.StringSliceReport, error) {
+	switch {
+	case options.Latest:
+		return nil, errors.New("latest is not supported")
+	case options.NameOrID == "":
+		return nil, errors.New("NameOrID must be specified")
+	}
+
+	topOutput, err := pods.Top(ic.ClientCxt, options.NameOrID, options.Descriptors)
+	if err != nil {
+		return nil, err
+	}
+	return &entities.StringSliceReport{Value: topOutput}, nil
+}