Add support for experimental Cli configuration

Allow to mark some commands and flags experimental on cli (i.e. not
depending to the state of the daemon). This will allow more flexibility
on experimentation with the cli.

Marking `docker trust` as cli experimental as it is documented so.

Signed-off-by: Vincent Demeester <vincent@sbr.pm>

cli/command/cli.go

@@ -42,24 +42,25 @@ type Cli interface {
 	SetIn(in *InStream)
 	ConfigFile() *configfile.ConfigFile
 	ServerInfo() ServerInfo
+	ClientInfo() ClientInfo
 	NotaryClient(imgRefAndAuth trust.ImageRefAndAuth, actions []string) (notaryclient.Repository, error)
 }
 
 // DockerCli is an instance the docker command line client.
 // Instances of the client can be returned from NewDockerCli.
 type DockerCli struct {
-	configFile     *configfile.ConfigFile
-	in             *InStream
-	out            *OutStream
-	err            io.Writer
-	client         client.APIClient
-	defaultVersion string
-	server         ServerInfo
+	configFile *configfile.ConfigFile
+	in         *InStream
+	out        *OutStream
+	err        io.Writer
+	client     client.APIClient
+	serverInfo ServerInfo
+	clientInfo ClientInfo
 }
 
 // DefaultVersion returns api.defaultVersion or DOCKER_API_VERSION if specified.
 func (cli *DockerCli) DefaultVersion() string {
-	return cli.defaultVersion
+	return cli.clientInfo.DefaultVersion
 }
 
 // Client returns the APIClient
@@ -104,7 +105,12 @@ func (cli *DockerCli) ConfigFile() *configfile.ConfigFile {
 // ServerInfo returns the server version details for the host this client is
 // connected to
 func (cli *DockerCli) ServerInfo() ServerInfo {
-	return cli.server
+	return cli.serverInfo
+}
+
+// ClientInfo returns the client details for the cli
+func (cli *DockerCli) ClientInfo() ClientInfo {
+	return cli.clientInfo
 }
 
 // Initialize the dockerCli runs initialization that must happen after command
@@ -125,17 +131,34 @@ func (cli *DockerCli) Initialize(opts *cliflags.ClientOptions) error {
 	if err != nil {
 		return err
 	}
+	hasExperimental, err := isEnabled(cli.configFile.Experimental)
+	if err != nil {
+		return errors.Wrap(err, "Experimental field")
+	}
+	cli.clientInfo = ClientInfo{
+		DefaultVersion:  cli.client.ClientVersion(),
+		HasExperimental: hasExperimental,
+	}
 	cli.initializeFromClient()
 	return nil
 }
 
-func (cli *DockerCli) initializeFromClient() {
-	cli.defaultVersion = cli.client.ClientVersion()
+func isEnabled(value string) (bool, error) {
+	switch value {
+	case "enabled":
+		return true, nil
+	case "", "disabled":
+		return false, nil
+	default:
+		return false, errors.Errorf("%q is not valid, should be either enabled or disabled", value)
+	}
+}
 
+func (cli *DockerCli) initializeFromClient() {
 	ping, err := cli.client.Ping(context.Background())
 	if err != nil {
 		// Default to true if we fail to connect to daemon
-		cli.server = ServerInfo{HasExperimental: true}
+		cli.serverInfo = ServerInfo{HasExperimental: true}
 
 		if ping.APIVersion != "" {
 			cli.client.NegotiateAPIVersionPing(ping)
@@ -143,7 +166,7 @@ func (cli *DockerCli) initializeFromClient() {
 		return
 	}
 
-	cli.server = ServerInfo{
+	cli.serverInfo = ServerInfo{
 		HasExperimental: ping.Experimental,
 		OSType:          ping.OSType,
 	}
@@ -176,6 +199,12 @@ type ServerInfo struct {
 	OSType          string
 }
 
+// ClientInfo stores details about the supported features of the client
+type ClientInfo struct {
+	HasExperimental bool
+	DefaultVersion  string
+}
+
 // NewDockerCli returns a DockerCli instance with IO output and error streams set by in, out and err.
 func NewDockerCli(in io.ReadCloser, out, err io.Writer) *DockerCli {
 	return &DockerCli{in: NewInStream(in), out: NewOutStream(out), err: err}

cli/command/cli_test.go

@@ -1,17 +1,18 @@
 package command
 
 import (
+	"crypto/x509"
 	"os"
 	"testing"
 
-	"crypto/x509"
-
+	cliconfig "github.com/docker/cli/cli/config"
 	"github.com/docker/cli/cli/config/configfile"
 	"github.com/docker/cli/cli/flags"
 	"github.com/docker/cli/internal/test/testutil"
 	"github.com/docker/docker/api"
 	"github.com/docker/docker/api/types"
 	"github.com/docker/docker/client"
+	"github.com/gotestyourself/gotestyourself/fs"
 	"github.com/pkg/errors"
 	"github.com/stretchr/testify/assert"
 	"github.com/stretchr/testify/require"
@@ -124,13 +125,51 @@ func TestInitializeFromClient(t *testing.T) {
 
 			cli := &DockerCli{client: apiclient}
 			cli.initializeFromClient()
-			assert.Equal(t, defaultVersion, cli.defaultVersion)
-			assert.Equal(t, testcase.expectedServer, cli.server)
+			assert.Equal(t, testcase.expectedServer, cli.serverInfo)
 			assert.Equal(t, testcase.negotiated, apiclient.negotiated)
 		})
 	}
 }
 
+func TestExperimentalCLI(t *testing.T) {
+	defaultVersion := "v1.55"
+
+	var testcases = []struct {
+		doc                     string
+		configfile              string
+		expectedExperimentalCLI bool
+	}{
+		{
+			doc:                     "default",
+			configfile:              `{}`,
+			expectedExperimentalCLI: false,
+		},
+		{
+			doc: "experimental",
+			configfile: `{
+	"experimental": "enabled"
+}`,
+			expectedExperimentalCLI: true,
+		},
+	}
+
+	for _, testcase := range testcases {
+		t.Run(testcase.doc, func(t *testing.T) {
+			dir := fs.NewDir(t, testcase.doc, fs.WithFile("config.json", testcase.configfile))
+			defer dir.Remove()
+			apiclient := &fakeClient{
+				version: defaultVersion,
+			}
+
+			cli := &DockerCli{client: apiclient, err: os.Stderr}
+			cliconfig.SetDir(dir.Path())
+			err := cli.Initialize(flags.NewClientOptions())
+			assert.NoError(t, err)
+			assert.Equal(t, testcase.expectedExperimentalCLI, cli.ClientInfo().HasExperimental)
+		})
+	}
+}
+
 func TestGetClientWithPassword(t *testing.T) {
 	expected := "password"
 

cli/command/system/version.go

@@ -23,6 +23,7 @@ Client:{{if ne .Platform.Name ""}} {{.Platform.Name}}{{end}}
  Git commit:	{{.GitCommit}}
  Built:	{{.BuildTime}}
  OS/Arch:	{{.Os}}/{{.Arch}}
+ Experimental:	{{.Experimental}}
 {{- end}}
 
 {{- if .ServerOK}}{{with .Server}}
@@ -69,6 +70,7 @@ type clientVersion struct {
 	Os                string
 	Arch              string
 	BuildTime         string `json:",omitempty"`
+	Experimental      bool
 }
 
 // ServerOK returns true when the client could connect to the docker server
@@ -133,6 +135,7 @@ func runVersion(dockerCli *command.DockerCli, opts *versionOptions) error {
 			BuildTime:         cli.BuildTime,
 			Os:                runtime.GOOS,
 			Arch:              runtime.GOARCH,
+			Experimental:      dockerCli.ClientInfo().HasExperimental,
 		},
 	}
 	vd.Client.Platform.Name = cli.PlatformName

cli/command/trust/cmd.go

@@ -9,10 +9,11 @@ import (
 // NewTrustCommand returns a cobra command for `trust` subcommands
 func NewTrustCommand(dockerCli command.Cli) *cobra.Command {
 	cmd := &cobra.Command{
-		Use:   "trust",
-		Short: "Manage trust on Docker images (experimental)",
-		Args:  cli.NoArgs,
-		RunE:  command.ShowHelp(dockerCli.Err()),
+		Use:         "trust",
+		Short:       "Manage trust on Docker images (experimental)",
+		Args:        cli.NoArgs,
+		RunE:        command.ShowHelp(dockerCli.Err()),
+		Annotations: map[string]string{"experimentalCLI": ""},
 	}
 	cmd.AddCommand(
 		newViewCommand(dockerCli),