Use spf13/cobra for docker port

This fix is part of the effort to convert commands to spf13/cobra #23211.

Thif fix coverted command `docker port` to use spf13/cobra

Note: As part of this fix, a new function `RequiresMinMaxArgs(min int, max int)`
has been added in cli/required.go. This function restrict the args
to be at least min and at most max.

Signed-off-by: Yong Tang <yong.tang.github@outlook.com>

api/client/commands.go

@@ -19,7 +19,6 @@ func (cli *DockerCli) Command(name string) func(...string) error {
 		"login":   cli.CmdLogin,
 		"logout":  cli.CmdLogout,
 		"pause":   cli.CmdPause,
-		"port":    cli.CmdPort,
 		"ps":      cli.CmdPs,
 		"pull":    cli.CmdPull,
 		"push":    cli.CmdPush,

api/client/container/port.go

@@ -0,0 +1,80 @@
+package container
+
+import (
+	"fmt"
+	"strings"
+
+	"golang.org/x/net/context"
+
+	"github.com/docker/docker/api/client"
+	"github.com/docker/docker/cli"
+	"github.com/docker/go-connections/nat"
+	"github.com/spf13/cobra"
+)
+
+type portOptions struct {
+	container string
+
+	port string
+}
+
+// NewPortCommand creats a new cobra.Command for `docker port`
+func NewPortCommand(dockerCli *client.DockerCli) *cobra.Command {
+	var opts portOptions
+
+	cmd := &cobra.Command{
+		Use:   "port CONTAINER [PRIVATE_PORT[/PROTO]]",
+		Short: "List port mappings or a specific mapping for the container",
+		Args:  cli.RequiresMinMaxArgs(1, 2),
+		RunE: func(cmd *cobra.Command, args []string) error {
+			opts.container = args[0]
+			if len(args) > 1 {
+				opts.port = args[1]
+			}
+			return runPort(dockerCli, &opts)
+		},
+	}
+	cmd.SetFlagErrorFunc(flagErrorFunc)
+
+	return cmd
+}
+
+func runPort(dockerCli *client.DockerCli, opts *portOptions) error {
+	ctx := context.Background()
+
+	c, err := dockerCli.Client().ContainerInspect(ctx, opts.container)
+	if err != nil {
+		return err
+	}
+
+	if opts.port != "" {
+		port := opts.port
+		proto := "tcp"
+		parts := strings.SplitN(port, "/", 2)
+
+		if len(parts) == 2 && len(parts[1]) != 0 {
+			port = parts[0]
+			proto = parts[1]
+		}
+		natPort := port + "/" + proto
+		newP, err := nat.NewPort(proto, port)
+		if err != nil {
+			return err
+		}
+		if frontends, exists := c.NetworkSettings.Ports[newP]; exists && frontends != nil {
+			for _, frontend := range frontends {
+				fmt.Fprintf(dockerCli.Out(), "%s:%s\n", frontend.HostIP, frontend.HostPort)
+			}
+			return nil
+		}
+		return fmt.Errorf("Error: No public port '%s' published for %s", natPort, opts.container)
+	}
+
+	for from, frontends := range c.NetworkSettings.Ports {
+		for _, frontend := range frontends {
+			fmt.Fprintf(dockerCli.Out(), "%s -> %s:%s\n", from, frontend.HostIP, frontend.HostPort)
+		}
+	}
+
+	return nil
+}

api/client/port.go

@@ -1,61 +0,0 @@
-package client
-
-import (
-	"fmt"
-	"strings"
-
-	"golang.org/x/net/context"
-
-	Cli "github.com/docker/docker/cli"
-	flag "github.com/docker/docker/pkg/mflag"
-	"github.com/docker/go-connections/nat"
-)
-
-// CmdPort lists port mappings for a container.
-// If a private port is specified, it also shows the public-facing port that is NATed to the private port.
-//
-// Usage: docker port CONTAINER [PRIVATE_PORT[/PROTO]]
-func (cli *DockerCli) CmdPort(args ...string) error {
-	cmd := Cli.Subcmd("port", []string{"CONTAINER [PRIVATE_PORT[/PROTO]]"}, Cli.DockerCommands["port"].Description, true)
-	cmd.Require(flag.Min, 1)
-
-	cmd.ParseFlags(args, true)
-
-	c, err := cli.client.ContainerInspect(context.Background(), cmd.Arg(0))
-	if err != nil {
-		return err
-	}
-
-	if cmd.NArg() == 2 {
-		var (
-			port  = cmd.Arg(1)
-			proto = "tcp"
-			parts = strings.SplitN(port, "/", 2)
-		)
-
-		if len(parts) == 2 && len(parts[1]) != 0 {
-			port = parts[0]
-			proto = parts[1]
-		}
-		natPort := port + "/" + proto
-		newP, err := nat.NewPort(proto, port)
-		if err != nil {
-			return err
-		}
-		if frontends, exists := c.NetworkSettings.Ports[newP]; exists && frontends != nil {
-			for _, frontend := range frontends {
-				fmt.Fprintf(cli.out, "%s:%s\n", frontend.HostIP, frontend.HostPort)
-			}
-			return nil
-		}
-		return fmt.Errorf("Error: No public port '%s' published for %s", natPort, cmd.Arg(0))
-	}
-
-	for from, frontends := range c.NetworkSettings.Ports {
-		for _, frontend := range frontends {
-			fmt.Fprintf(cli.out, "%s -> %s:%s\n", from, frontend.HostIP, frontend.HostPort)
-		}
-	}
-
-	return nil
-}

cli/cobraadaptor/adaptor.go

@@ -38,6 +38,7 @@ func NewCobraAdaptor(clientFlags *cliflags.ClientFlags) CobraAdaptor {
 		container.NewDiffCommand(dockerCli),
 		container.NewExportCommand(dockerCli),
 		container.NewLogsCommand(dockerCli),
+		container.NewPortCommand(dockerCli),
 		container.NewRunCommand(dockerCli),
 		container.NewStartCommand(dockerCli),
 		container.NewStopCommand(dockerCli),

cli/required.go

@@ -43,6 +43,24 @@ func RequiresMinArgs(min int) cobra.PositionalArgs {
 	}
 }
 
+// RequiresMinMaxArgs returns an error if there is not at least min args and at most max args
+func RequiresMinMaxArgs(min int, max int) cobra.PositionalArgs {
+	return func(cmd *cobra.Command, args []string) error {
+		if len(args) >= min && len(args) <= max {
+			return nil
+		}
+		return fmt.Errorf(
+			"\"%s\" requires at least %d and at most %d argument(s).\nSee '%s --help'.\n\nUsage:  %s\n\n%s",
+			cmd.CommandPath(),
+			min,
+			max,
+			cmd.CommandPath(),
+			cmd.UseLine(),
+			cmd.Short,
+		)
+	}
+}
+
 // ExactArgs returns an error if there is not the exact number of args
 func ExactArgs(number int) cobra.PositionalArgs {
 	return func(cmd *cobra.Command, args []string) error {

cli/usage.go

@@ -24,7 +24,6 @@ var DockerCommandUsage = []Command{
 	{"login", "Log in to a Docker registry"},
 	{"logout", "Log out from a Docker registry"},
 	{"pause", "Pause all processes within a container"},
-	{"port", "List port mappings or a specific mapping for the CONTAINER"},
 	{"ps", "List containers"},
 	{"pull", "Pull an image or a repository from a registry"},
 	{"push", "Push an image or a repository to a registry"},