Add compose top

Signed-off-by: Jin Dong <jindon@amazon.com>

README.md

@@ -343,6 +343,7 @@ It does not necessarily mean that the corresponding features are missing in cont
     - [:whale: nerdctl compose restart](#whale-nerdctl-compose-restart)
     - [:whale: nerdctl compose rm](#whale-nerdctl-compose-rm)
     - [:whale: nerdctl compose run](#whale-nerdctl-compose-run)
+    - [:whale: nerdctl compose top](#whale-nerdctl-compose-top)
     - [:whale: nerdctl compose version](#whale-nerdctl-compose-version)
   - [IPFS management](#ipfs-management)
     - [:nerd_face: nerdctl ipfs registry up](#nerd_face-nerdctl-ipfs-registry-up)
@@ -1569,6 +1570,12 @@ Unimplemented `docker-compose run` (V1) flags: `--use-aliases`, `--no-TTY`
 
 Unimplemented `docker compose run` (V2) flags: `--use-aliases`, `--no-TTY`, `--tty`
 
+### :whale: nerdctl compose top
+
+Display the running processes of service containers
+
+Usage: `nerdctl compose top [SERVICES...]`
+
 ### :whale: nerdctl compose version
 Show the Compose version information (which is the nerdctl version)
 
@@ -1647,7 +1654,7 @@ Registry:
 - `docker search`
 
 Compose:
-- `docker-compose create|events|pause|port|scale|start|top|unpause`
+- `docker-compose create|events|pause|port|scale|start|unpause`
 
 Others:
 - `docker system df`

cmd/nerdctl/compose.go

@@ -70,6 +70,7 @@ func newComposeCommand() *cobra.Command {
 		newComposeRunCommand(),
 		newComposeVersionCommand(),
 		newComposeStopCommand(),
+		newComposeTopCommand(),
 	)
 
 	return composeCommand

cmd/nerdctl/compose_top.go

@@ -0,0 +1,83 @@
+/*
+   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 (
+	"fmt"
+
+	"github.com/containerd/containerd"
+	"github.com/containerd/nerdctl/pkg/labels"
+	"github.com/spf13/cobra"
+)
+
+func newComposeTopCommand() *cobra.Command {
+	var composeTopCommand = &cobra.Command{
+		Use:                   "top [SERVICE...]",
+		Short:                 "Display the running processes of service containers",
+		RunE:                  composeTopAction,
+		SilenceUsage:          true,
+		SilenceErrors:         true,
+		DisableFlagsInUseLine: true,
+	}
+	return composeTopCommand
+}
+
+func composeTopAction(cmd *cobra.Command, args []string) error {
+	client, ctx, cancel, err := newClient(cmd)
+	if err != nil {
+		return err
+	}
+	defer cancel()
+
+	c, err := getComposer(cmd, client)
+	if err != nil {
+		return err
+	}
+	serviceNames, err := c.ServiceNames(args...)
+	if err != nil {
+		return err
+	}
+	containers, err := c.Containers(ctx, serviceNames...)
+	if err != nil {
+		return err
+	}
+
+	stdout := cmd.OutOrStdout()
+	for _, c := range containers {
+		cStatus, err := containerStatus(ctx, c)
+		if err != nil {
+			return err
+		}
+		if cStatus.Status != containerd.Running {
+			continue
+		}
+
+		info, err := c.Info(ctx, containerd.WithoutRefreshedMetadata)
+		if err != nil {
+			return err
+		}
+		fmt.Fprintf(stdout, "%s\n", info.Labels[labels.Name])
+		// `compose ps` uses empty ps args
+		err = containerTop(ctx, cmd, client, c.ID(), "")
+		if err != nil {
+			return err
+		}
+		fmt.Fprintln(stdout)
+	}
+
+	return nil
+}

cmd/nerdctl/compose_top_linux_test.go

@@ -0,0 +1,56 @@
+/*
+   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 (
+	"fmt"
+	"testing"
+
+	"github.com/containerd/nerdctl/pkg/infoutil"
+	"github.com/containerd/nerdctl/pkg/rootlessutil"
+	"github.com/containerd/nerdctl/pkg/testutil"
+)
+
+func TestComposeTop(t *testing.T) {
+	if rootlessutil.IsRootless() && infoutil.CgroupsVersion() == "1" {
+		t.Skip("test skipped for rootless containers on cgroup v1")
+	}
+
+	base := testutil.NewBase(t)
+	var dockerComposeYAML = fmt.Sprintf(`
+version: '3.1'
+
+services:
+  svc0:
+    image: %s
+    command: "sleep infinity"
+  svc1:
+    image: %s
+`, testutil.CommonImage, testutil.NginxAlpineImage)
+
+	comp := testutil.NewComposeDir(t, dockerComposeYAML)
+	defer comp.CleanUp()
+	projectName := comp.ProjectName()
+	t.Logf("projectName=%q", projectName)
+
+	base.ComposeCmd("-f", comp.YAMLFullPath(), "up", "-d").AssertOK()
+	defer base.ComposeCmd("-f", comp.YAMLFullPath(), "down", "-v").AssertOK()
+
+	// a running container should have the process command in output
+	base.ComposeCmd("-f", comp.YAMLFullPath(), "top", "svc0").AssertOutContains("sleep infinity")
+	base.ComposeCmd("-f", comp.YAMLFullPath(), "top", "svc1").AssertOutContains("nginx")
+}