podmanV2: implement top

Implement the `top` command for podmanV2.

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

2 files changed, 67 insertions, 2 deletions

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())
+	})
 })