Fix complexity of service/ps.

Signed-off-by: Daniel Nephin <dnephin@docker.com>

cli/command/service/ps.go

@@ -12,6 +12,7 @@ import (
 	"github.com/docker/cli/opts"
 	"github.com/docker/docker/api/types"
 	"github.com/docker/docker/api/types/filters"
+	"github.com/docker/docker/client"
 	"github.com/pkg/errors"
 	"github.com/spf13/cobra"
 	"golang.org/x/net/context"
@@ -52,6 +53,34 @@ func runPS(dockerCli command.Cli, options psOptions) error {
 	client := dockerCli.Client()
 	ctx := context.Background()
 
+	filter, notfound, err := createFilter(ctx, client, options)
+	if err != nil {
+		return err
+	}
+
+	tasks, err := client.TaskList(ctx, types.TaskListOptions{Filters: filter})
+	if err != nil {
+		return err
+	}
+
+	format := options.format
+	if len(format) == 0 {
+		if len(dockerCli.ConfigFile().TasksFormat) > 0 && !options.quiet {
+			format = dockerCli.ConfigFile().TasksFormat
+		} else {
+			format = formatter.TableFormatKey
+		}
+	}
+	if err := task.Print(ctx, dockerCli, tasks, idresolver.New(client, options.noResolve), !options.noTrunc, options.quiet, format); err != nil {
+		return err
+	}
+	if len(notfound) != 0 {
+		return errors.New(strings.Join(notfound, "\n"))
+	}
+	return nil
+}
+
+func createFilter(ctx context.Context, client client.APIClient, options psOptions) (filters.Args, []string, error) {
 	filter := options.filter.Value()
 
 	serviceIDFilter := filters.NewArgs()
@@ -62,14 +91,14 @@ func runPS(dockerCli command.Cli, options psOptions) error {
 	}
 	serviceByIDList, err := client.ServiceList(ctx, types.ServiceListOptions{Filters: serviceIDFilter})
 	if err != nil {
-		return err
+		return filter, nil, err
 	}
 	serviceByNameList, err := client.ServiceList(ctx, types.ServiceListOptions{Filters: serviceNameFilter})
 	if err != nil {
-		return err
+		return filter, nil, err
 	}
 
-	var errs []string
+	var notfound []string
 	serviceCount := 0
 loop:
 	// Match services by 1. Full ID, 2. Full name, 3. ID prefix. An error is returned if the ID-prefix match is ambiguous
@@ -92,50 +121,30 @@ loop:
 		for _, s := range serviceByIDList {
 			if strings.HasPrefix(s.ID, service) {
 				if found {
-					return errors.New("multiple services found with provided prefix: " + service)
+					return filter, nil, errors.New("multiple services found with provided prefix: " + service)
 				}
 				filter.Add("service", s.ID)
 				serviceCount++
 				found = true
 			}
 		}
 		if !found {
-			errs = append(errs, "no such service: "+service)
+			notfound = append(notfound, "no such service: "+service)
 		}
 	}
 	if serviceCount == 0 {
-		return errors.New(strings.Join(errs, "\n"))
+		return filter, nil, errors.New(strings.Join(notfound, "\n"))
 	}
 	if filter.Include("node") {
 		nodeFilters := filter.Get("node")
 		for _, nodeFilter := range nodeFilters {
 			nodeReference, err := node.Reference(ctx, client, nodeFilter)
 			if err != nil {
-				return err
+				return filter, nil, err
 			}
 			filter.Del("node", nodeFilter)
 			filter.Add("node", nodeReference)
 		}
 	}
-
-	tasks, err := client.TaskList(ctx, types.TaskListOptions{Filters: filter})
-	if err != nil {
-		return err
-	}
-
-	format := options.format
-	if len(format) == 0 {
-		if len(dockerCli.ConfigFile().TasksFormat) > 0 && !options.quiet {
-			format = dockerCli.ConfigFile().TasksFormat
-		} else {
-			format = formatter.TableFormatKey
-		}
-	}
-	if err := task.Print(ctx, dockerCli, tasks, idresolver.New(client, options.noResolve), !options.noTrunc, options.quiet, format); err != nil {
-		return err
-	}
-	if len(errs) != 0 {
-		return errors.New(strings.Join(errs, "\n"))
-	}
-	return nil
+	return filter, nil, err
 }