Add podman pod top

Using the vendored changes from psgo, incorporate JoinNamespaceAndProcessInfoByPids to get process information for each pid namespace of running containers in the pod. Also added a man page, and tests.

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

Closes: #1298
Approved by: mheon

2 files changed, 102 insertions, 0 deletions

diff --git a/cmd/podman/pod.go b/cmd/podman/pod.go
index e691204d8..dde43f77c 100644
--- a/cmd/podman/pod.go
+++ b/cmd/podman/pod.go
@@ -20,6 +20,7 @@ Pods are a group of one or more containers sharing the same network, pid and ipc
 		podStartCommand,
 		podStatsCommand,
 		podStopCommand,
+		podTopCommand,
 		podUnpauseCommand,
 	}
 	podCommand = cli.Command{
diff --git a/cmd/podman/pod_top.go b/cmd/podman/pod_top.go
new file mode 100644
index 000000000..703ec0a44
--- /dev/null
+++ b/cmd/podman/pod_top.go
@@ -0,0 +1,101 @@
+package main
+
+import (
+	"fmt"
+	"os"
+	"strings"
+	"text/tabwriter"
+
+	"github.com/containers/libpod/cmd/podman/libpodruntime"
+	"github.com/containers/libpod/cmd/podman/shared"
+	"github.com/containers/libpod/libpod"
+	"github.com/pkg/errors"
+	"github.com/urfave/cli"
+)
+
+var (
+	podTopFlags = []cli.Flag{
+		LatestFlag,
+		cli.BoolFlag{
+			Name:   "list-descriptors",
+			Hidden: true,
+		},
+	}
+	podTopDescription = fmt.Sprintf(`Display the running processes containers in a pod.  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.
+%s
+`, getDescriptorString())
+
+	podTopCommand = cli.Command{
+		Name:           "top",
+		Usage:          "Display the running processes of containers in a pod",
+		Description:    podTopDescription,
+		Flags:          podTopFlags,
+		Action:         podTopCmd,
+		ArgsUsage:      "POD-NAME [format descriptors]",
+		SkipArgReorder: true,
+	}
+)
+
+func podTopCmd(c *cli.Context) error {
+	var pod *libpod.Pod
+	var err error
+	args := c.Args()
+
+	if c.Bool("list-descriptors") {
+		descriptors, err := libpod.GetContainerPidInformationDescriptors()
+		if err != nil {
+			return err
+		}
+		fmt.Println(strings.Join(descriptors, "\n"))
+		return nil
+	}
+
+	if len(args) < 1 && !c.Bool("latest") {
+		return errors.Errorf("you must provide the name or id of a running pod")
+	}
+	if err := validateFlags(c, podTopFlags); err != nil {
+		return err
+	}
+
+	runtime, err := libpodruntime.GetRuntime(c)
+	if err != nil {
+		return errors.Wrapf(err, "error creating libpod runtime")
+	}
+	defer runtime.Shutdown(false)
+
+	var descriptors []string
+	if c.Bool("latest") {
+		descriptors = args
+		pod, err = runtime.GetLatestPod()
+	} else {
+		descriptors = args[1:]
+		pod, err = runtime.LookupPod(args[0])
+	}
+
+	if err != nil {
+		return errors.Wrapf(err, "unable to lookup requested container")
+	}
+
+	podStatus, err := shared.GetPodStatus(pod)
+	if err != nil {
+		return err
+	}
+	if podStatus != "Running" {
+		return errors.Errorf("pod top can only be used on pods with at least one running container")
+	}
+
+	psOutput, err := pod.GetPodPidInformation(descriptors)
+	if err != nil {
+		return err
+	}
+
+	w := tabwriter.NewWriter(os.Stdout, 5, 1, 3, ' ', 0)
+	for _, proc := range psOutput {
+		fmt.Fprintln(w, proc)
+	}
+	w.Flush()
+	return nil
+}