podmanV2: implement top

Implement the `top` command for podmanV2.

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

7 files changed, 214 insertions, 2 deletions

diff --git a/cmd/podmanV2/containers/top.go b/cmd/podmanV2/containers/top.go
new file mode 100644
index 000000000..a86c12e2a
--- /dev/null
+++ b/cmd/podmanV2/containers/top.go
@@ -0,0 +1,91 @@
+package containers
+
+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(`Similar to system "top" command.
+
+  Specify format descriptors to alter the output.
+
+  Running "podman top -l pid pcpu seccomp" will print the process ID, the CPU percentage and the seccomp mode of each process of the latest container.
+  Format Descriptors:
+    %s`, strings.Join(psgo.ListDescriptors(), ","))
+
+	topOptions = entities.TopOptions{}
+
+	topCommand = &cobra.Command{
+		Use:               "top [flags] CONTAINER [FORMAT-DESCRIPTORS|ARGS]",
+		Short:             "Display the running processes of a container",
+		Long:              topDescription,
+		PersistentPreRunE: preRunE,
+		RunE:              top,
+		Args:              cobra.ArbitraryArgs,
+		Example: `podman top ctrID
+podman top --latest
+podman top ctrID pid seccomp args %C
+podman top ctrID -eo user,pid,comm`,
+	}
+)
+
+func init() {
+	registry.Commands = append(registry.Commands, registry.CliCommand{
+		Mode:    []entities.EngineMode{entities.ABIMode, entities.TunnelMode},
+		Command: topCommand,
+	})
+
+	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 container")
+	}
+
+	if topOptions.Latest {
+		topOptions.Descriptors = args
+	} else {
+		topOptions.NameOrID = args[0]
+		topOptions.Descriptors = args[1:]
+	}
+
+	topResponse, err := registry.ContainerEngine().ContainerTop(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()
+}
diff --git a/pkg/bindings/containers/containers.go b/pkg/bindings/containers/containers.go
index c2f10345f..bad1294f4 100644
--- a/pkg/bindings/containers/containers.go
+++ b/pkg/bindings/containers/containers.go
@@ -5,8 +5,10 @@ import (
 	"net/http"
 	"net/url"
 	"strconv"
+	"strings"
 
 	"github.com/containers/libpod/libpod/define"
+	"github.com/containers/libpod/pkg/api/handlers"
 	lpapiv2 "github.com/containers/libpod/pkg/api/handlers/libpod"
 	"github.com/containers/libpod/pkg/bindings"
 )
@@ -193,7 +195,40 @@ func Start(ctx context.Context, nameOrID string, detachKeys *string) error {
 }
 
 func Stats() {}
-func Top()   {}
+
+// Top gathers statistics about the running processes in a container. The nameOrID can be a container name
+// or a partial/full ID.  The descriptors allow for specifying which data to collect from the 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, "/containers/%s/top", params, nameOrID)
+	if err != nil {
+		return nil, err
+	}
+
+	body := handlers.ContainerTopOKBody{}
+	if err = response.Process(&body); err != nil {
+		return nil, err
+	}
+
+	// handlers.ContainerTopOKBody{} 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 resumes the given paused container.  The nameOrID can be a container name
 // or a partial/full ID.
diff --git a/pkg/bindings/test/containers_test.go b/pkg/bindings/test/containers_test.go
index 55c739865..9dd9cb707 100644
--- a/pkg/bindings/test/containers_test.go
+++ b/pkg/bindings/test/containers_test.go
@@ -34,7 +34,7 @@ var _ = Describe("Podman containers ", func() {
 
 	AfterEach(func() {
 		s.Kill()
-		//bt.cleanup()
+		bt.cleanup()
 	})
 
 	It("podman pause a bogus container", func() {
@@ -380,4 +380,34 @@ var _ = Describe("Podman containers ", func() {
 		_, err = time.Parse(time.RFC1123Z, o)
 		Expect(err).To(BeNil())
 	})
+
+	It("podman top", func() {
+		var name = "top"
+		cid, err := bt.RunTopContainer(&name, &bindings.PFalse, nil)
+		Expect(err).To(BeNil())
+
+		// By name
+		output, err := containers.Top(bt.conn, name, nil)
+		Expect(err).To(BeNil())
+
+		// By id
+		output, err = containers.Top(bt.conn, cid, nil)
+		Expect(err).To(BeNil())
+
+		// With descriptors
+		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"} {
+			Expect(d).To(BeElementOf(header))
+		}
+
+		// With bogus ID
+		_, err = containers.Top(bt.conn, "IdoNotExist", nil)
+		Expect(err).ToNot(BeNil())
+
+		// With bogus descriptors
+		_, err = containers.Top(bt.conn, cid, []string{"Me,Neither"})
+		Expect(err).To(BeNil())
+	})
 })
diff --git a/pkg/domain/entities/containers.go b/pkg/domain/entities/containers.go
index 545452948..fbc0247ab 100644
--- a/pkg/domain/entities/containers.go
+++ b/pkg/domain/entities/containers.go
@@ -22,6 +22,11 @@ type BoolReport struct {
 	Value bool
 }
 
+// StringSliceReport wraps a string slice.
+type StringSliceReport struct {
+	Value []string
+}
+
 type PauseUnPauseOptions struct {
 	All bool
 }
@@ -44,6 +49,16 @@ type StopReport struct {
 	Id  string
 }
 
+type TopOptions struct {
+	// CLI flags.
+	ListDescriptors bool
+	Latest          bool
+
+	// Options for the API.
+	Descriptors []string
+	NameOrID    string
+}
+
 type KillOptions struct {
 	All    bool
 	Latest bool
diff --git a/pkg/domain/entities/engine_container.go b/pkg/domain/entities/engine_container.go
index 0217910fc..21a674c43 100644
--- a/pkg/domain/entities/engine_container.go
+++ b/pkg/domain/entities/engine_container.go
@@ -14,6 +14,8 @@ type ContainerEngine interface {
 	ContainerUnpause(ctx context.Context, namesOrIds []string, options PauseUnPauseOptions) ([]*PauseUnpauseReport, error)
 	ContainerStop(ctx context.Context, namesOrIds []string, options StopOptions) ([]*StopReport, error)
 	ContainerWait(ctx context.Context, namesOrIds []string, options WaitOptions) ([]WaitReport, error)
+	ContainerTop(ctx context.Context, options TopOptions) (*StringSliceReport, error)
+
 	PodExists(ctx context.Context, nameOrId string) (*BoolReport, error)
 	PodKill(ctx context.Context, namesOrIds []string, options PodKillOptions) ([]*PodKillReport, error)
 	PodPause(ctx context.Context, namesOrIds []string, options PodPauseOptions) ([]*PodPauseReport, error)
@@ -22,6 +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)
+
 	VolumeCreate(ctx context.Context, opts VolumeCreateOptions) (*IdOrNameResponse, error)
 	VolumeInspect(ctx context.Context, namesOrIds []string, opts VolumeInspectOptions) ([]*VolumeInspectReport, error)
 	VolumeRm(ctx context.Context, namesOrIds []string, opts VolumeRmOptions) ([]*VolumeRmReport, error)
diff --git a/pkg/domain/infra/abi/containers.go b/pkg/domain/infra/abi/containers.go
index 2e1a5aa82..3965c5f75 100644
--- a/pkg/domain/infra/abi/containers.go
+++ b/pkg/domain/infra/abi/containers.go
@@ -255,3 +255,25 @@ func (ic *ContainerEngine) ContainerInspect(ctx context.Context, namesOrIds []st
 	}
 	return reports, nil
 }
+
+func (ic *ContainerEngine) ContainerTop(ctx context.Context, options entities.TopOptions) (*entities.StringSliceReport, error) {
+	var (
+		container *libpod.Container
+		err       error
+	)
+
+	// Look up the container.
+	if options.Latest {
+		container, err = ic.Libpod.GetLatestContainer()
+	} else {
+		container, err = ic.Libpod.LookupContainer(options.NameOrID)
+	}
+	if err != nil {
+		return nil, errors.Wrap(err, "unable to lookup requested container")
+	}
+
+	// Run Top.
+	report := &entities.StringSliceReport{}
+	report.Value, err = container.Top(options.Descriptors)
+	return report, err
+}
diff --git a/pkg/domain/infra/tunnel/containers.go b/pkg/domain/infra/tunnel/containers.go
index 367ea6e36..3db38ea5c 100644
--- a/pkg/domain/infra/tunnel/containers.go
+++ b/pkg/domain/infra/tunnel/containers.go
@@ -5,6 +5,7 @@ import (
 
 	"github.com/containers/libpod/pkg/bindings/containers"
 	"github.com/containers/libpod/pkg/domain/entities"
+	"github.com/pkg/errors"
 )
 
 func (ic *ContainerEngine) ContainerExists(ctx context.Context, nameOrId string) (*entities.BoolReport, error) {
@@ -156,3 +157,18 @@ func (ic *ContainerEngine) ContainerInspect(ctx context.Context, namesOrIds []st
 	}
 	return reports, nil
 }
+
+func (ic *ContainerEngine) ContainerTop(ctx context.Context, options entities.TopOptions) (*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 := containers.Top(ic.ClientCxt, options.NameOrID, options.Descriptors)
+	if err != nil {
+		return nil, err
+	}
+	return &entities.StringSliceReport{Value: topOutput}, nil
+}