setup docker top cmd

Signed-off-by: fahed dorgaa <fahed.dorgaa@gmail.com>

top.go

@@ -0,0 +1,134 @@
+/*
+   Copyright The containerd 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 (
+	"github.com/containerd/containerd"
+	"github.com/pkg/errors"
+	"github.com/urfave/cli/v2"
+	"regexp"
+)
+
+var topCommand = &cli.Command{
+	Name:         "top",
+	Usage:        "docker top CONTAINER",
+	ArgsUsage:    "CONTAINER [ps OPTIONS]",
+	Action:       topAction,
+	BashComplete: topBashComplete,
+}
+
+func topAction(clicontext *cli.Context) error {
+	if clicontext.NArg() < 1 {
+		return errors.Errorf("requires at least 1 argument")
+	}
+    //TODO
+}
+
+//function from moby/moby
+func validatePSArgs(psArgs string) error {
+	// NOTE: \\s does not detect unicode whitespaces.
+	// So we use fieldsASCII instead of strings.Fields in parsePSOutput.
+	// See https://github.com/docker/docker/pull/24358
+	// nolint: gosimple
+	re := regexp.MustCompile("\\s+([^\\s]*)=\\s*(PID[^\\s]*)")
+	for _, group := range re.FindAllStringSubmatch(psArgs, -1) {
+		if len(group) >= 3 {
+			k := group[1]
+			v := group[2]
+			if k != "pid" {
+				return fmt.Errorf("specifying \"%s=%s\" is not allowed", k, v)
+			}
+		}
+	}
+	return nil
+}
+
+//function from moby/moby
+// ContainerTop lists the processes running inside of the given
+// container by calling ps with the given args, or with the flags
+// "-ef" if no args are given.  An error is returned if the container
+// is not found, or is not running, or if there are any problems
+// running ps, or parsing the output.
+func (daemon *Daemon) ContainerTop(clicontext *cli.Context, name string, psArgs string) (*container.ContainerTopOKBody, error) {
+	if psArgs == "" {
+		psArgs = "-ef"
+	}
+
+	if err := validatePSArgs(psArgs); err != nil {
+		return nil, err
+	}
+
+    client, ctx, cancel, err := newClient(clicontext)
+    if err != nil {
+     return err
+    }
+    defer cancel()
+
+    container, err := client.LoadContainer(ctx, name)
+    if err != nil {
+     return err
+    }
+
+	task, err := container.Task(ctx, nil)
+    if err != nil {
+     return err
+    }
+
+    status, err := task.Status(ctx)
+    if err != nil {
+     return err
+    }
+
+	if status.Status != containerd.Running {
+		return nil, errNotRunning(ctr.ID)
+	}
+
+	if ctr.IsRestarting() {
+		return nil, errContainerIsRestarting(ctr.ID)
+	}
+
+	procs, err := containerd.ListPids(context.Background(), ctr.ID)
+	if err != nil {
+		return nil, err
+	}
+
+	args := strings.Split(psArgs, " ")
+	pids := psPidsArg(procs)
+	output, err := exec.Command("ps", append(args, pids)...).Output()
+	if err != nil {
+		// some ps options (such as f) can't be used together with q,
+		// so retry without it
+		output, err = exec.Command("ps", args...).Output()
+		if err != nil {
+			if ee, ok := err.(*exec.ExitError); ok {
+				// first line of stderr shows why ps failed
+				line := bytes.SplitN(ee.Stderr, []byte{'\n'}, 2)
+				if len(line) > 0 && len(line[0]) > 0 {
+					err = errors.New(string(line[0]))
+				}
+			}
+			return nil, errdefs.System(errors.Wrap(err, "ps"))
+		}
+	}
+	procList, err := parsePSOutput(output, procs)
+	if err != nil {
+		return nil, err
+	}
+	//daemon.LogContainerEvent(ctr, "top")
+	return procList, nil
+}
+