Merge pull request #27745 from vieux/cli_backward_compose_api

allow client to talk to an older server

command/checkpoint/cmd.go

@@ -1,8 +1,6 @@
 package checkpoint
 
 import (
-	"fmt"
-
 	"github.com/docker/docker/cli"
 	"github.com/docker/docker/cli/command"
 	"github.com/spf13/cobra"
@@ -15,9 +13,10 @@ func NewCheckpointCommand(dockerCli *command.DockerCli) *cobra.Command {
 		Short: "Manage checkpoints",
 		Args:  cli.NoArgs,
 		Run: func(cmd *cobra.Command, args []string) {
-			fmt.Fprintf(dockerCli.Err(), "\n"+cmd.UsageString())
+			cmd.SetOutput(dockerCli.Err())
+			cmd.HelpFunc()(cmd, args)
 		},
-		Tags: map[string]string{"experimental": ""},
+		Tags: map[string]string{"experimental": "", "version": "1.25"},
 	}
 	cmd.AddCommand(
 		newCreateCommand(dockerCli),

command/cli.go

@@ -10,6 +10,7 @@ import (
 	"runtime"
 
 	"github.com/docker/docker/api"
+	"github.com/docker/docker/api/types/versions"
 	cliflags "github.com/docker/docker/cli/flags"
 	"github.com/docker/docker/cliconfig"
 	"github.com/docker/docker/cliconfig/configfile"
@@ -38,15 +39,18 @@ type DockerCli struct {
 	err             io.Writer
 	keyFile         string
 	client          client.APIClient
+	hasExperimental bool
+	defaultVersion  string
 }
 
-// HasExperimental returns true if experimental features are accessible
+// HasExperimental returns true if experimental features are accessible.
 func (cli *DockerCli) HasExperimental() bool {
-	if cli.client == nil {
-		return false
+	return cli.hasExperimental
 }
-	enabled, _ := cli.client.Ping(context.Background())
-	return enabled
+
+// DefaultVersion returns api.defaultVersion of DOCKER_API_VERSION if specified.
+func (cli *DockerCli) DefaultVersion() string {
+	return cli.defaultVersion
 }
 
 // Client returns the APIClient
@@ -93,12 +97,28 @@ func (cli *DockerCli) Initialize(opts *cliflags.ClientOptions) error {
 	if err != nil {
 		return err
 	}
+
+	cli.defaultVersion = cli.client.ClientVersion()
+
 	if opts.Common.TrustKey == "" {
 		cli.keyFile = filepath.Join(cliconfig.ConfigDir(), cliflags.DefaultTrustKeyFile)
 	} else {
 		cli.keyFile = opts.Common.TrustKey
 	}
 
+	if ping, err := cli.client.Ping(context.Background()); err == nil {
+		cli.hasExperimental = ping.Experimental
+
+		// since the new header was added in 1.25, assume server is 1.24 if header is not present.
+		if ping.APIVersion == "" {
+			ping.APIVersion = "1.24"
+		}
+
+		// if server version is lower than the current cli, downgrade
+		if versions.LessThan(ping.APIVersion, cli.client.ClientVersion()) {
+			cli.client.UpdateClientVersion(ping.APIVersion)
+		}
+	}
 	return nil
 }
 

command/container/cmd.go

@@ -1,8 +1,6 @@
 package container
 
 import (
-	"fmt"
-
 	"github.com/spf13/cobra"
 
 	"github.com/docker/docker/cli"
@@ -16,7 +14,8 @@ func NewContainerCommand(dockerCli *command.DockerCli) *cobra.Command {
 		Short: "Manage containers",
 		Args:  cli.NoArgs,
 		Run: func(cmd *cobra.Command, args []string) {
-			fmt.Fprintf(dockerCli.Err(), "\n"+cmd.UsageString())
+			cmd.SetOutput(dockerCli.Err())
+			cmd.HelpFunc()(cmd, args)
 		},
 	}
 	cmd.AddCommand(

command/container/exec.go

@@ -59,6 +59,7 @@ func NewExecCommand(dockerCli *command.DockerCli) *cobra.Command {
 	flags.StringVarP(&opts.user, "user", "u", "", "Username or UID (format: <name|uid>[:<group|gid>])")
 	flags.BoolVarP(&opts.privileged, "privileged", "", false, "Give extended privileges to the command")
 	flags.VarP(opts.env, "env", "e", "Set environment variables")
+	flags.SetAnnotation("env", "version", []string{"1.25"})
 
 	return cmd
 }

command/container/prune.go

@@ -35,6 +35,7 @@ func NewPruneCommand(dockerCli *command.DockerCli) *cobra.Command {
 			fmt.Fprintln(dockerCli.Out(), "Total reclaimed space:", units.HumanSize(float64(spaceReclaimed)))
 			return nil
 		},
+		Tags: map[string]string{"version": "1.25"},
 	}
 
 	flags := cmd.Flags()

command/image/build.go

@@ -113,6 +113,7 @@ func NewBuildCommand(dockerCli *command.DockerCli) *cobra.Command {
 
 	flags.BoolVar(&options.squash, "squash", false, "Squash newly built layers into a single new layer")
 	flags.SetAnnotation("squash", "experimental", nil)
+	flags.SetAnnotation("squash", "version", []string{"1.25"})
 
 	return cmd
 }

command/image/cmd.go

@@ -1,8 +1,6 @@
 package image
 
 import (
-	"fmt"
-
 	"github.com/spf13/cobra"
 
 	"github.com/docker/docker/cli"
@@ -16,7 +14,8 @@ func NewImageCommand(dockerCli *command.DockerCli) *cobra.Command {
 		Short: "Manage images",
 		Args:  cli.NoArgs,
 		Run: func(cmd *cobra.Command, args []string) {
-			fmt.Fprintf(dockerCli.Err(), "\n"+cmd.UsageString())
+			cmd.SetOutput(dockerCli.Err())
+			cmd.HelpFunc()(cmd, args)
 		},
 	}
 	cmd.AddCommand(
@@ -33,6 +32,5 @@ func NewImageCommand(dockerCli *command.DockerCli) *cobra.Command {
 		newInspectCommand(dockerCli),
 		NewPruneCommand(dockerCli),
 	)
-
 	return cmd
 }

command/image/prune.go

@@ -36,6 +36,7 @@ func NewPruneCommand(dockerCli *command.DockerCli) *cobra.Command {
 			fmt.Fprintln(dockerCli.Out(), "Total reclaimed space:", units.HumanSize(float64(spaceReclaimed)))
 			return nil
 		},
+		Tags: map[string]string{"version": "1.25"},
 	}
 
 	flags := cmd.Flags()

command/network/cmd.go

@@ -1,8 +1,6 @@
 package network
 
 import (
-	"fmt"
-
 	"github.com/spf13/cobra"
 
 	"github.com/docker/docker/cli"
@@ -16,7 +14,8 @@ func NewNetworkCommand(dockerCli *command.DockerCli) *cobra.Command {
 		Short: "Manage networks",
 		Args:  cli.NoArgs,
 		Run: func(cmd *cobra.Command, args []string) {
-			fmt.Fprintf(dockerCli.Err(), "\n"+cmd.UsageString())
+			cmd.SetOutput(dockerCli.Err())
+			cmd.HelpFunc()(cmd, args)
 		},
 	}
 	cmd.AddCommand(

command/network/prune.go

@@ -33,6 +33,7 @@ func NewPruneCommand(dockerCli *command.DockerCli) *cobra.Command {
 			}
 			return nil
 		},
+		Tags: map[string]string{"version": "1.25"},
 	}
 
 	flags := cmd.Flags()

command/node/cmd.go

@@ -1,8 +1,6 @@
 package node
 
 import (
-	"fmt"
-
 	"github.com/docker/docker/cli"
 	"github.com/docker/docker/cli/command"
 	apiclient "github.com/docker/docker/client"
@@ -17,7 +15,8 @@ func NewNodeCommand(dockerCli *command.DockerCli) *cobra.Command {
 		Short: "Manage Swarm nodes",
 		Args:  cli.NoArgs,
 		Run: func(cmd *cobra.Command, args []string) {
-			fmt.Fprintf(dockerCli.Err(), "\n"+cmd.UsageString())
+			cmd.SetOutput(dockerCli.Err())
+			cmd.HelpFunc()(cmd, args)
 		},
 	}
 	cmd.AddCommand(

command/plugin/cmd.go

@@ -1,8 +1,6 @@
 package plugin
 
 import (
-	"fmt"
-
 	"github.com/docker/docker/cli"
 	"github.com/docker/docker/cli/command"
 	"github.com/spf13/cobra"
@@ -15,7 +13,8 @@ func NewPluginCommand(dockerCli *command.DockerCli) *cobra.Command {
 		Short: "Manage plugins",
 		Args:  cli.NoArgs,
 		Run: func(cmd *cobra.Command, args []string) {
-			fmt.Fprintf(dockerCli.Err(), "\n"+cmd.UsageString())
+			cmd.SetOutput(dockerCli.Err())
+			cmd.HelpFunc()(cmd, args)
 		},
 		Tags: map[string]string{"experimental": ""},
 	}

command/service/cmd.go

@@ -1,8 +1,6 @@
 package service
 
 import (
-	"fmt"
-
 	"github.com/spf13/cobra"
 
 	"github.com/docker/docker/cli"
@@ -16,7 +14,8 @@ func NewServiceCommand(dockerCli *command.DockerCli) *cobra.Command {
 		Short: "Manage services",
 		Args:  cli.NoArgs,
 		Run: func(cmd *cobra.Command, args []string) {
-			fmt.Fprintf(dockerCli.Err(), "\n"+cmd.UsageString())
+			cmd.SetOutput(dockerCli.Err())
+			cmd.HelpFunc()(cmd, args)
 		},
 	}
 	cmd.AddCommand(

command/stack/cmd.go

@@ -1,8 +1,6 @@
 package stack
 
 import (
-	"fmt"
-
 	"github.com/docker/docker/cli"
 	"github.com/docker/docker/cli/command"
 	"github.com/spf13/cobra"
@@ -15,9 +13,10 @@ func NewStackCommand(dockerCli *command.DockerCli) *cobra.Command {
 		Short: "Manage Docker stacks",
 		Args:  cli.NoArgs,
 		Run: func(cmd *cobra.Command, args []string) {
-			fmt.Fprintf(dockerCli.Err(), "\n"+cmd.UsageString())
+			cmd.SetOutput(dockerCli.Err())
+			cmd.HelpFunc()(cmd, args)
 		},
-		Tags: map[string]string{"experimental": ""},
+		Tags: map[string]string{"experimental": "", "version": "1.25"},
 	}
 	cmd.AddCommand(
 		newConfigCommand(dockerCli),

command/stack/deploy.go

@@ -36,7 +36,7 @@ func newDeployCommand(dockerCli *command.DockerCli) *cobra.Command {
 			opts.namespace = strings.TrimSuffix(args[0], ".dab")
 			return runDeploy(dockerCli, opts)
 		},
-		Tags: map[string]string{"experimental": ""},
+		Tags: map[string]string{"experimental": "", "version": "1.25"},
 	}
 
 	flags := cmd.Flags()

command/swarm/cmd.go

@@ -1,8 +1,6 @@
 package swarm
 
 import (
-	"fmt"
-
 	"github.com/spf13/cobra"
 
 	"github.com/docker/docker/cli"
@@ -16,7 +14,8 @@ func NewSwarmCommand(dockerCli *command.DockerCli) *cobra.Command {
 		Short: "Manage Swarm",
 		Args:  cli.NoArgs,
 		Run: func(cmd *cobra.Command, args []string) {
-			fmt.Fprintf(dockerCli.Err(), "\n"+cmd.UsageString())
+			cmd.SetOutput(dockerCli.Err())
+			cmd.HelpFunc()(cmd, args)
 		},
 	}
 	cmd.AddCommand(

command/system/cmd.go

@@ -1,8 +1,6 @@
 package system
 
 import (
-	"fmt"
-
 	"github.com/spf13/cobra"
 
 	"github.com/docker/docker/cli"
@@ -16,7 +14,8 @@ func NewSystemCommand(dockerCli *command.DockerCli) *cobra.Command {
 		Short: "Manage Docker",
 		Args:  cli.NoArgs,
 		Run: func(cmd *cobra.Command, args []string) {
-			fmt.Fprintf(dockerCli.Err(), "\n"+cmd.UsageString())
+			cmd.SetOutput(dockerCli.Err())
+			cmd.HelpFunc()(cmd, args)
 		},
 	}
 	cmd.AddCommand(
@@ -25,5 +24,6 @@ func NewSystemCommand(dockerCli *command.DockerCli) *cobra.Command {
 		NewDiskUsageCommand(dockerCli),
 		NewPruneCommand(dockerCli),
 	)
+
 	return cmd
 }

command/system/df.go

@@ -23,6 +23,7 @@ func NewDiskUsageCommand(dockerCli *command.DockerCli) *cobra.Command {
 		RunE: func(cmd *cobra.Command, args []string) error {
 			return runDiskUsage(dockerCli, opts)
 		},
+		Tags: map[string]string{"version": "1.25"},
 	}
 
 	flags := cmd.Flags()

command/system/prune.go

@@ -26,6 +26,7 @@ func NewPruneCommand(dockerCli *command.DockerCli) *cobra.Command {
 		RunE: func(cmd *cobra.Command, args []string) error {
 			return runPrune(dockerCli, opts)
 		},
+		Tags: map[string]string{"version": "1.25"},
 	}
 
 	flags := cmd.Flags()

command/system/version.go

@@ -1,6 +1,7 @@
 package system
 
 import (
+	"fmt"
 	"runtime"
 	"time"
 
@@ -70,10 +71,15 @@ func runVersion(dockerCli *command.DockerCli, opts *versionOptions) error {
 			Status: "Template parsing error: " + err.Error()}
 	}
 
+	APIVersion := dockerCli.Client().ClientVersion()
+	if defaultAPIVersion := dockerCli.DefaultVersion(); APIVersion != defaultAPIVersion {
+		APIVersion = fmt.Sprintf("%s (downgraded from %s)", APIVersion, defaultAPIVersion)
+	}
+
 	vd := types.VersionResponse{
 		Client: &types.Version{
 			Version:    dockerversion.Version,
-			APIVersion: dockerCli.Client().ClientVersion(),
+			APIVersion: APIVersion,
 			GoVersion:  runtime.Version(),
 			GitCommit:  dockerversion.GitCommit,
 			BuildTime:  dockerversion.BuildTime,

command/volume/cmd.go

@@ -1,8 +1,6 @@
 package volume
 
 import (
-	"fmt"
-
 	"github.com/spf13/cobra"
 
 	"github.com/docker/docker/cli"
@@ -17,7 +15,8 @@ func NewVolumeCommand(dockerCli *command.DockerCli) *cobra.Command {
 		Long:  volumeDescription,
 		Args:  cli.NoArgs,
 		Run: func(cmd *cobra.Command, args []string) {
-			fmt.Fprintf(dockerCli.Err(), "\n"+cmd.UsageString())
+			cmd.SetOutput(dockerCli.Err())
+			cmd.HelpFunc()(cmd, args)
 		},
 	}
 	cmd.AddCommand(

command/volume/prune.go

@@ -35,6 +35,7 @@ func NewPruneCommand(dockerCli *command.DockerCli) *cobra.Command {
 			fmt.Fprintln(dockerCli.Out(), "Total reclaimed space:", units.HumanSize(float64(spaceReclaimed)))
 			return nil
 		},
+		Tags: map[string]string{"version": "1.25"},
 	}
 
 	flags := cmd.Flags()

command/volume/remove.go

@@ -34,7 +34,7 @@ func newRemoveCommand(dockerCli *command.DockerCli) *cobra.Command {
 
 	flags := cmd.Flags()
 	flags.BoolVarP(&opts.force, "force", "f", false, "Force the removal of one or more volumes")
-
+	flags.SetAnnotation("force", "version", []string{"1.25"})
 	return cmd
 }