PRIVATE_PORT optional for docker compose port

Signed-off-by: Max Proske <max@mproske.com>

Author: maxproske

cmd/compose/port.go

@@ -19,6 +19,8 @@ package compose
 import (
 	"context"
 	"fmt"
+	"net"
+	"sort"
 	"strconv"
 	"strings"
 
@@ -41,16 +43,20 @@ func portCommand(p *ProjectOptions, dockerCli command.Cli, backendOptions *Backe
 		ProjectOptions: p,
 	}
 	cmd := &cobra.Command{
-		Use:   "port [OPTIONS] SERVICE PRIVATE_PORT",
-		Short: "Print the public port for a port binding",
-		Args:  cobra.MinimumNArgs(2),
+		Use:   "port [OPTIONS] SERVICE [PRIVATE_PORT]",
+		Short: "List port mappings or print the public port of a specific mapping for the service",
+		Args:  cobra.RangeArgs(1, 2),
 		PreRunE: Adapt(func(ctx context.Context, args []string) error {
-			port, err := strconv.ParseUint(args[1], 10, 16)
-			if err != nil {
-				return err
-			}
-			opts.port = uint16(port)
 			opts.protocol = strings.ToLower(opts.protocol)
+			if len(args) > 1 {
+				port, err := strconv.ParseUint(args[1], 10, 16)
+				if err != nil {
+					return err
+				}
+				opts.port = uint16(port)
+			} else {
+				opts.protocol = ""
+			}
 			return nil
 		}),
 		RunE: Adapt(func(ctx context.Context, args []string) error {
@@ -73,14 +79,22 @@ func runPort(ctx context.Context, dockerCli command.Cli, backendOptions *Backend
 	if err != nil {
 		return err
 	}
-	ip, port, err := backend.Port(ctx, projectName, service, opts.port, api.PortOptions{
+	publishers, err := backend.Ports(ctx, projectName, service, opts.port, api.PortOptions{
 		Protocol: opts.protocol,
 		Index:    opts.index,
 	})
 	if err != nil {
 		return err
 	}
 
-	_, _ = fmt.Fprintf(dockerCli.Out(), "%s:%d\n", ip, port)
+	if opts.port != 0 && len(publishers) > 0 {
+		p := publishers[0]
+		_, _ = fmt.Fprintf(dockerCli.Out(), "%s\n", net.JoinHostPort(p.URL, strconv.Itoa(p.PublishedPort)))
+		return nil
+	}
+	sort.Sort(publishers)
+	for _, p := range publishers {
+		_, _ = fmt.Fprintln(dockerCli.Out(), p.String())
+	}
 	return nil
 }

docs/reference/compose.md

@@ -28,7 +28,7 @@ Define and run multi-container applications with Docker
 | [`logs`](compose_logs.md)       | View output from containers                                                             |
 | [`ls`](compose_ls.md)           | List running compose projects                                                           |
 | [`pause`](compose_pause.md)     | Pause services                                                                          |
-| [`port`](compose_port.md)       | Print the public port for a port binding                                                |
+| [`port`](compose_port.md)       | List port mappings or print the public port of a specific mapping for the service       |
 | [`ps`](compose_ps.md)           | List containers                                                                         |
 | [`publish`](compose_publish.md) | Publish compose application                                                             |
 | [`pull`](compose_pull.md)       | Pull service images                                                                     |

docs/reference/compose_port.md

@@ -1,7 +1,7 @@
 # docker compose port
 
 <!---MARKER_GEN_START-->
-Prints the public port for a port binding
+List port mappings or print the public port of a specific mapping for the service
 
 ### Options
 
@@ -16,4 +16,4 @@ Prints the public port for a port binding
 
 ## Description
 
-Prints the public port for a port binding
+List port mappings or print the public port of a specific mapping for the service

docs/reference/docker_compose_port.yaml

@@ -1,7 +1,9 @@
 command: docker compose port
-short: Print the public port for a port binding
-long: Prints the public port for a port binding
-usage: docker compose port [OPTIONS] SERVICE PRIVATE_PORT
+short: |
+    List port mappings or print the public port of a specific mapping for the service
+long: |
+    List port mappings or print the public port of a specific mapping for the service
+usage: docker compose port [OPTIONS] SERVICE [PRIVATE_PORT]
 pname: docker compose
 plink: docker_compose.yaml
 options:

pkg/api/api.go

@@ -20,7 +20,9 @@ import (
 	"context"
 	"fmt"
 	"io"
+	"net"
 	"slices"
+	"strconv"
 	"strings"
 	"time"
 
@@ -125,8 +127,8 @@ type Compose interface {
 	Top(ctx context.Context, projectName string, services []string) ([]ContainerProcSummary, error)
 	// Events executes the equivalent to a `compose events`
 	Events(ctx context.Context, projectName string, options EventsOptions) error
-	// Port executes the equivalent to a `compose port`
-	Port(ctx context.Context, projectName string, service string, port uint16, options PortOptions) (string, int, error)
+	// Ports executes the equivalent to a `compose port`
+	Ports(ctx context.Context, projectName string, service string, port uint16, options PortOptions) (PortPublishers, error)
 	// Publish executes the equivalent to a `compose publish`
 	Publish(ctx context.Context, project *types.Project, repository string, options PublishOptions) error
 	// Images executes the equivalent of a `compose images`
@@ -535,6 +537,10 @@ type PortPublisher struct {
 	Protocol      string
 }
 
+func (p PortPublisher) String() string {
+	return fmt.Sprintf("%d/%s -> %s", p.TargetPort, p.Protocol, net.JoinHostPort(p.URL, strconv.Itoa(p.PublishedPort)))
+}
+
 // ContainerSummary hold high-level description of a container
 type ContainerSummary struct {
 	ID           string

pkg/api/api_test.go

@@ -23,6 +23,22 @@ import (
 	"gotest.tools/v3/assert"
 )
 
+func TestPortPublisherString(t *testing.T) {
+	tests := []struct {
+		name string
+		pub  PortPublisher
+		want string
+	}{
+		{"ipv4", PortPublisher{URL: "0.0.0.0", TargetPort: 80, PublishedPort: 8080, Protocol: "tcp"}, "80/tcp -> 0.0.0.0:8080"},
+		{"ipv6", PortPublisher{URL: "::", TargetPort: 5060, PublishedPort: 32769, Protocol: "udp"}, "5060/udp -> [::]:32769"},
+	}
+	for _, tt := range tests {
+		t.Run(tt.name, func(t *testing.T) {
+			assert.Equal(t, tt.pub.String(), tt.want)
+		})
+	}
+}
+
 func TestRunOptionsEnvironmentMap(t *testing.T) {
 	opts := RunOptions{
 		Environment: []string{

pkg/compose/port.go

@@ -26,18 +26,40 @@ import (
 	"github.com/docker/compose/v5/pkg/api"
 )
 
-func (s *composeService) Port(ctx context.Context, projectName string, service string, port uint16, options api.PortOptions) (string, int, error) {
+func (s *composeService) Ports(ctx context.Context, projectName string, service string, port uint16, options api.PortOptions) (api.PortPublishers, error) {
 	projectName = strings.ToLower(projectName)
 	ctr, err := s.getSpecifiedContainer(ctx, projectName, oneOffInclude, false, service, options.Index)
 	if err != nil {
-		return "", 0, err
+		return nil, err
 	}
+
+	if port != 0 {
+		for _, p := range ctr.Ports {
+			if p.PrivatePort == port && p.Type == options.Protocol {
+				return api.PortPublishers{{
+					URL:           p.IP.String(),
+					TargetPort:    int(p.PrivatePort),
+					PublishedPort: int(p.PublicPort),
+					Protocol:      p.Type,
+				}}, nil
+			}
+		}
+		return nil, portNotFoundError(options.Protocol, port, ctr)
+	}
+
+	var publishers api.PortPublishers
 	for _, p := range ctr.Ports {
-		if p.PrivatePort == port && p.Type == options.Protocol {
-			return p.IP.String(), int(p.PublicPort), nil
+		if options.Protocol != "" && p.Type != options.Protocol {
+			continue
 		}
+		publishers = append(publishers, api.PortPublisher{
+			URL:           p.IP.String(),
+			TargetPort:    int(p.PrivatePort),
+			PublishedPort: int(p.PublicPort),
+			Protocol:      p.Type,
+		})
 	}
-	return "", 0, portNotFoundError(options.Protocol, port, ctr)
+	return publishers, nil
 }
 
 func portNotFoundError(protocol string, port uint16, ctr container.Summary) error {