add `docker stack ls`

Signed-off-by: Akihiro Suda <suda.akihiro@lab.ntt.co.jp>

command/stack/cmd_experimental.go

@@ -23,6 +23,7 @@ func NewStackCommand(dockerCli *command.DockerCli) *cobra.Command {
 	cmd.AddCommand(
 		newConfigCommand(dockerCli),
 		newDeployCommand(dockerCli),
+		newListCommand(dockerCli),
 		newRemoveCommand(dockerCli),
 		newServicesCommand(dockerCli),
 		newPsCommand(dockerCli),

command/stack/list.go

@@ -0,0 +1,119 @@
+// +build experimental
+
+package stack
+
+import (
+	"fmt"
+	"io"
+	"strconv"
+	"text/tabwriter"
+
+	"golang.org/x/net/context"
+
+	"github.com/docker/docker/api/types"
+	"github.com/docker/docker/api/types/filters"
+	"github.com/docker/docker/cli"
+	"github.com/docker/docker/cli/command"
+	"github.com/docker/docker/client"
+	"github.com/spf13/cobra"
+)
+
+const (
+	listItemFmt = "%s\t%s\n"
+)
+
+type listOptions struct {
+}
+
+func newListCommand(dockerCli *command.DockerCli) *cobra.Command {
+	opts := listOptions{}
+
+	cmd := &cobra.Command{
+		Use:     "ls",
+		Aliases: []string{"list"},
+		Short:   "List stacks",
+		Args:    cli.NoArgs,
+		RunE: func(cmd *cobra.Command, args []string) error {
+			return runList(dockerCli, opts)
+		},
+	}
+
+	return cmd
+}
+
+func runList(dockerCli *command.DockerCli, opts listOptions) error {
+	client := dockerCli.Client()
+	ctx := context.Background()
+
+	stacks, err := getStacks(ctx, client)
+	if err != nil {
+		return err
+	}
+
+	out := dockerCli.Out()
+	printTable(out, stacks)
+	return nil
+}
+
+func printTable(out io.Writer, stacks []*stack) {
+	writer := tabwriter.NewWriter(out, 0, 4, 2, ' ', 0)
+
+	// Ignore flushing errors
+	defer writer.Flush()
+
+	fmt.Fprintf(writer, listItemFmt, "NAME", "SERVICES")
+	for _, stack := range stacks {
+		fmt.Fprintf(
+			writer,
+			listItemFmt,
+			stack.Name,
+			strconv.Itoa(stack.Services),
+		)
+	}
+}
+
+type stack struct {
+	// Name is the name of the stack
+	Name string
+	// Services is the number of the services
+	Services int
+}
+
+func getStacks(
+	ctx context.Context,
+	apiclient client.APIClient,
+) ([]*stack, error) {
+
+	filter := filters.NewArgs()
+	filter.Add("label", labelNamespace)
+
+	services, err := apiclient.ServiceList(
+		ctx,
+		types.ServiceListOptions{Filter: filter})
+	if err != nil {
+		return nil, err
+	}
+	m := make(map[string]*stack, 0)
+	for _, service := range services {
+		labels := service.Spec.Labels
+		name, ok := labels[labelNamespace]
+		if !ok {
+			return nil, fmt.Errorf("cannot get label %s for service %s",
+				labelNamespace, service.ID)
+		}
+		ztack, ok := m[name]
+		if !ok {
+			m[name] = &stack{
+				Name:     name,
+				Services: 1,
+			}
+		} else {
+			ztack.Services++
+		}
+	}
+	var stacks []*stack
+	for _, stack := range m {
+		stacks = append(stacks, stack)
+	}
+	return stacks, nil
+}

command/stack/services.go

@@ -16,10 +16,6 @@ import (
 	"github.com/spf13/cobra"
 )
 
-const (
-	listItemFmt = "%s\t%s\t%s\t%s\t%s\n"
-)
-
 type servicesOptions struct {
 	quiet     bool
 	filter    opts.FilterOpt