Improve service tasks grouping on printing

When printing services' tasks with `docker service ps` command, tasks are grouped only by task slot.
This leads to interleaving tasks from different services when `docker service ps` is called with multiple services.

Besides this, global services do not have slots at all and printing tasks for them doesn't group and
doesn't properly indent tasks with \_.

With this patch all tasks are grouped by service ID, slot and node ID (relevant only for global services) and it fixes issue 533.

Before this patch:

```console
docker service ps a b c

ID                  NAME                              IMAGE               NODE                DESIRED STATE       CURRENT STATE                     ERROR               PORTS
xbzm6ed776yw        c.j1afavbqqhr21jvnid3nnfoyt       nginx:alpine        docker-desktop      Running             Running 5 seconds ago
4mcsovp8ckwn         \_ c.j1afavbqqhr21jvnid3nnfoyt   nginx:alpine        docker-desktop      Shutdown            Shutdown 6 seconds ago
qpcgdsx1r21a        b.1                               nginx:alpine        docker-desktop      Running             Running 2 seconds ago
kfjo1hly92l4        a.1                               nginx:alpine        docker-desktop      Running             Running 5 seconds ago
pubrerosvsw5        b.1                               nginx:alpine        docker-desktop      Shutdown            Shutdown 3 seconds ago
fu08gfi8tfyv        a.1                               nginx:alpine        docker-desktop      Shutdown            Shutdown 7 seconds ago
pu6qmgyoibq4        b.2                               nginx:alpine        docker-desktop      Running             Ready 1 second ago
tz1n4hjne6pk         \_ b.2                           nginx:alpine        docker-desktop      Shutdown            Shutdown less than a second ago
xq8dogqcbxd2        a.2                               nginx:alpine        docker-desktop      Running             Running 44 seconds ago
rm40lofzed0h        a.3                               nginx:alpine        docker-desktop      Running             Starting less than a second ago
sqqj2n9fpi82        b.3                               nginx:alpine        docker-desktop      Running             Running 5 seconds ago
prv3gymkvqk6         \_ b.3                           nginx:alpine        docker-desktop      Shutdown            Shutdown 6 seconds ago
qn7c7jmjuo76        a.3                               nginx:alpine        docker-desktop      Shutdown            Shutdown less than a second ago
wi9330mbabpg        a.4                               nginx:alpine        docker-desktop      Running             Running 2 seconds ago
p5oy6h7nkvc3         \_ a.4                           nginx:alpine        docker-desktop      Shutdown            Shutdown 3 seconds ago
```

After this patch:

```console
docker service ps a b c

ID                  NAME                              IMAGE               NODE                DESIRED STATE       CURRENT STATE             ERROR               PORTS
kfjo1hly92l4        a.1                               nginx:alpine        docker-desktop      Running             Running 32 seconds ago
fu08gfi8tfyv         \_ a.1                           nginx:alpine        docker-desktop      Shutdown            Shutdown 34 seconds ago
3pam0limnn24        a.2                               nginx:alpine        docker-desktop      Running             Running 23 seconds ago
xq8dogqcbxd2         \_ a.2                           nginx:alpine        docker-desktop      Shutdown            Shutdown 24 seconds ago
rm40lofzed0h        a.3                               nginx:alpine        docker-desktop      Running             Running 26 seconds ago
qn7c7jmjuo76         \_ a.3                           nginx:alpine        docker-desktop      Shutdown            Shutdown 27 seconds ago
wi9330mbabpg        a.4                               nginx:alpine        docker-desktop      Running             Running 29 seconds ago
p5oy6h7nkvc3         \_ a.4                           nginx:alpine        docker-desktop      Shutdown            Shutdown 30 seconds ago
qpcgdsx1r21a        b.1                               nginx:alpine        docker-desktop      Running             Running 29 seconds ago
pubrerosvsw5         \_ b.1                           nginx:alpine        docker-desktop      Shutdown            Shutdown 30 seconds ago
pu6qmgyoibq4        b.2                               nginx:alpine        docker-desktop      Running             Running 26 seconds ago
tz1n4hjne6pk         \_ b.2                           nginx:alpine        docker-desktop      Shutdown            Shutdown 27 seconds ago
sqqj2n9fpi82        b.3                               nginx:alpine        docker-desktop      Running             Running 32 seconds ago
prv3gymkvqk6         \_ b.3                           nginx:alpine        docker-desktop      Shutdown            Shutdown 33 seconds ago
xbzm6ed776yw        c.j1afavbqqhr21jvnid3nnfoyt       nginx:alpine        docker-desktop      Running             Running 32 seconds ago
4mcsovp8ckwn         \_ c.j1afavbqqhr21jvnid3nnfoyt   nginx:alpine        docker-desktop      Shutdown            Shutdown 33 seconds ago
```

Signed-off-by: Andrii Berehuliak <berkusandrew@gmail.com>
Signed-off-by: Sebastiaan van Stijn <github@gone.nl>

cli/command/task/print.go

@@ -10,25 +10,24 @@ import (
 	"github.com/docker/cli/cli/command/idresolver"
 	"github.com/docker/cli/cli/config/configfile"
 	"github.com/docker/docker/api/types/swarm"
+	"vbom.ml/util/sortorder"
 )
 
-type tasksBySlot []swarm.Task
+type tasksSortable []swarm.Task
 
-func (t tasksBySlot) Len() int {
+func (t tasksSortable) Len() int {
 	return len(t)
 }
 
-func (t tasksBySlot) Swap(i, j int) {
+func (t tasksSortable) Swap(i, j int) {
 	t[i], t[j] = t[j], t[i]
 }
 
-func (t tasksBySlot) Less(i, j int) bool {
+func (t tasksSortable) Less(i, j int) bool {
-	// Sort by slot.
+	if t[i].Name != t[j].Name {
-	if t[i].Slot != t[j].Slot {
+		return sortorder.NaturalLess(t[i].Name, t[j].Name)
-		return t[i].Slot < t[j].Slot
 	}
-
+	// Sort tasks for the same service and slot by most recent.
-	// If same slot, sort by most recent.
 	return t[j].Meta.CreatedAt.Before(t[i].CreatedAt)
 }
 
@@ -36,7 +35,15 @@ func (t tasksBySlot) Less(i, j int) bool {
 // Besides this, command `docker node ps <node>`
 // and `docker stack ps` will call this, too.
 func Print(ctx context.Context, dockerCli command.Cli, tasks []swarm.Task, resolver *idresolver.IDResolver, trunc, quiet bool, format string) error {
-	sort.Stable(tasksBySlot(tasks))
+	tasks, err := generateTaskNames(ctx, tasks, resolver)
+	if err != nil {
+		return err
+	}
+
+	// First sort tasks, so that all tasks (including previous ones) of the same
+	// service and slot are together. This must be done first, to print "previous"
+	// tasks indented
+	sort.Stable(tasksSortable(tasks))
 
 	names := map[string]string{}
 	nodes := map[string]string{}
@@ -47,42 +54,57 @@ func Print(ctx context.Context, dockerCli command.Cli, tasks []swarm.Task, resol
 		Trunc:  trunc,
 	}
 
+	var indent string
+	if tasksCtx.Format.IsTable() {
+		indent = ` \_ `
+	}
 	prevName := ""
 	for _, task := range tasks {
-		serviceName, err := resolver.Resolve(ctx, swarm.Service{}, task.ServiceID)
+		if task.Name == prevName {
-		if err != nil {
+			// Indent previous tasks of the same slot
-			return err
+			names[task.ID] = indent + task.Name
+		} else {
+			names[task.ID] = task.Name
 		}
+		prevName = task.Name
 
 		nodeValue, err := resolver.Resolve(ctx, swarm.Node{}, task.NodeID)
 		if err != nil {
 			return err
 		}
-
-		var name string
-		if task.Slot != 0 {
-			name = fmt.Sprintf("%v.%v", serviceName, task.Slot)
-		} else {
-			name = fmt.Sprintf("%v.%v", serviceName, task.NodeID)
-		}
-
-		// Indent the name if necessary
-		indentedName := name
-		if name == prevName {
-			indentedName = fmt.Sprintf(" \\_ %s", indentedName)
-		}
-		prevName = name
-
-		names[task.ID] = name
-		if tasksCtx.Format.IsTable() {
-			names[task.ID] = indentedName
-		}
 		nodes[task.ID] = nodeValue
 	}
 
 	return FormatWrite(tasksCtx, tasks, names, nodes)
 }
 
+// generateTaskNames generates names for the given tasks, and returns a copy of
+// the slice with the 'Name' field set.
+//
+// Depending if the "--no-resolve" option is set, names have the following pattern:
+//
+// - ServiceName.Slot or ServiceID.Slot for tasks that are part of a replicated service
+// - ServiceName.NodeName or ServiceID.NodeID for tasks that are part of a global service
+//
+// Task-names are not unique in cases where "tasks" contains previous/rotated tasks.
+func generateTaskNames(ctx context.Context, tasks []swarm.Task, resolver *idresolver.IDResolver) ([]swarm.Task, error) {
+	// Use a copy of the tasks list, to not modify the original slice
+	t := append(tasks[:0:0], tasks...)
+
+	for i, task := range t {
+		serviceName, err := resolver.Resolve(ctx, swarm.Service{}, task.ServiceID)
+		if err != nil {
+			return nil, err
+		}
+		if task.Slot != 0 {
+			t[i].Name = fmt.Sprintf("%v.%v", serviceName, task.Slot)
+		} else {
+			t[i].Name = fmt.Sprintf("%v.%v", serviceName, task.NodeID)
+		}
+	}
+	return t, nil
+}
+
 // DefaultFormat returns the default format from the config file, or table
 // format if nothing is set in the config.
 func DefaultFormat(configFile *configfile.ConfigFile, quiet bool) string {

cli/command/task/print_test.go

@@ -15,6 +15,41 @@ import (
 	"gotest.tools/golden"
 )
 
+func TestTaskPrintSorted(t *testing.T) {
+	apiClient := &fakeClient{
+		serviceInspectWithRaw: func(ref string, options types.ServiceInspectOptions) (swarm.Service, []byte, error) {
+			if ref == "service-id-one" {
+				return *Service(ServiceName("service-name-1")), nil, nil
+			}
+			return *Service(ServiceName("service-name-10")), nil, nil
+		},
+	}
+
+	cli := test.NewFakeCli(apiClient)
+	tasks := []swarm.Task{
+		*Task(
+			TaskID("id-foo"),
+			TaskServiceID("service-id-ten"),
+			TaskNodeID("id-node"),
+			WithTaskSpec(TaskImage("myimage:mytag")),
+			TaskDesiredState(swarm.TaskStateReady),
+			WithStatus(TaskState(swarm.TaskStateFailed), Timestamp(time.Now().Add(-2*time.Hour))),
+		),
+		*Task(
+			TaskID("id-bar"),
+			TaskServiceID("service-id-one"),
+			TaskNodeID("id-node"),
+			WithTaskSpec(TaskImage("myimage:mytag")),
+			TaskDesiredState(swarm.TaskStateReady),
+			WithStatus(TaskState(swarm.TaskStateFailed), Timestamp(time.Now().Add(-2*time.Hour))),
+		),
+	}
+
+	err := Print(context.Background(), cli, tasks, idresolver.New(apiClient, false), false, false, formatter.TableFormatKey)
+	assert.NilError(t, err)
+	golden.Assert(t, cli.OutBuffer().String(), "task-print-sorted.golden")
+}
+
 func TestTaskPrintWithQuietOption(t *testing.T) {
 	quiet := true
 	trunc := false

cli/command/task/testdata/task-print-sorted.golden

@@ -0,0 +1,3 @@
+ID                  NAME                IMAGE               NODE                DESIRED STATE       CURRENT STATE        ERROR               PORTS
+id-bar              service-name-1.1    myimage:mytag       id-node             Ready               Failed 2 hours ago                       
+id-foo              service-name-10.1   myimage:mytag       id-node             Ready               Failed 2 hours ago