Always enable experimental features

The CLI disabled experimental features by default, requiring users
to set a configuration option to enable them.

Disabling experimental features was a request from Enterprise users
that did not want experimental features to be accessible.

We are changing this policy, and now enable experimental features
by default. Experimental features may still change and/or removed,
and will be highlighted in the documentation and "usage" output.

For example, the `docker manifest inspect --help` output now shows:

    EXPERIMENTAL:
      docker manifest inspect is an experimental feature.

      Experimental features provide early access to product functionality. These features
      may change between releases without warning or can be removed entirely from a future
      release. Learn more about experimental features: https://docs.docker.com/go/experimental/

Signed-off-by: Sebastiaan van Stijn <github@gone.nl>

cli-plugins/examples/helloworld/main.go

@@ -101,6 +101,5 @@ func main() {
 			SchemaVersion: "0.1.0",
 			Vendor:        "Docker Inc.",
 			Version:       "testing",
-			Experimental:  os.Getenv("HELLO_EXPERIMENTAL") != "",
 		})
 }

cli-plugins/manager/candidate_test.go

@@ -12,10 +12,9 @@ import (
 )
 
 type fakeCandidate struct {
-	path              string
-	exec              bool
-	meta              string
-	allowExperimental bool
+	path string
+	exec bool
+	meta string
 }
 
 func (c *fakeCandidate) Path() string {
@@ -30,7 +29,7 @@ func (c *fakeCandidate) Metadata() ([]byte, error) {
 }
 
 func TestValidateCandidate(t *testing.T) {
-	var (
+	const (
 		goodPluginName = NamePrefix + "goodplugin"
 
 		builtinName  = NamePrefix + "builtin"
@@ -70,14 +69,12 @@ func TestValidateCandidate(t *testing.T) {
 		{name: "invalid schemaversion", c: &fakeCandidate{path: goodPluginPath, exec: true, meta: `{"SchemaVersion": "xyzzy"}`}, invalid: `plugin SchemaVersion "xyzzy" is not valid`},
 		{name: "no vendor", c: &fakeCandidate{path: goodPluginPath, exec: true, meta: `{"SchemaVersion": "0.1.0"}`}, invalid: "plugin metadata does not define a vendor"},
 		{name: "empty vendor", c: &fakeCandidate{path: goodPluginPath, exec: true, meta: `{"SchemaVersion": "0.1.0", "Vendor": ""}`}, invalid: "plugin metadata does not define a vendor"},
-		{name: "experimental required", c: &fakeCandidate{path: goodPluginPath, exec: true, meta: metaExperimental}, invalid: "requires experimental CLI"},
 		// This one should work
 		{name: "valid", c: &fakeCandidate{path: goodPluginPath, exec: true, meta: `{"SchemaVersion": "0.1.0", "Vendor": "e2e-testing"}`}},
-		{name: "valid + allowing experimental", c: &fakeCandidate{path: goodPluginPath, exec: true, meta: `{"SchemaVersion": "0.1.0", "Vendor": "e2e-testing"}`, allowExperimental: true}},
-		{name: "experimental + allowing experimental", c: &fakeCandidate{path: goodPluginPath, exec: true, meta: metaExperimental, allowExperimental: true}},
+		{name: "experimental + allowing experimental", c: &fakeCandidate{path: goodPluginPath, exec: true, meta: metaExperimental}},
 	} {
 		t.Run(tc.name, func(t *testing.T) {
-			p, err := newPlugin(tc.c, fakeroot, tc.c.allowExperimental)
+			p, err := newPlugin(tc.c, fakeroot)
 			if tc.err != "" {
 				assert.ErrorContains(t, err, tc.err)
 			} else if tc.invalid != "" {

cli-plugins/manager/manager.go

@@ -1,7 +1,6 @@
 package manager
 
 import (
-	"fmt"
 	"io/ioutil"
 	"os"
 	"os/exec"
@@ -30,16 +29,6 @@ func (e errPluginNotFound) Error() string {
 	return "Error: No such CLI plugin: " + string(e)
 }
 
-type errPluginRequireExperimental string
-
-// Note: errPluginRequireExperimental implements notFound so that the plugin
-// is skipped when listing the plugins.
-func (e errPluginRequireExperimental) NotFound() {}
-
-func (e errPluginRequireExperimental) Error() string {
-	return fmt.Sprintf("plugin candidate %q: requires experimental CLI", string(e))
-}
-
 type notFound interface{ NotFound() }
 
 // IsNotFound is true if the given error is due to a plugin not being found.
@@ -133,7 +122,7 @@ func ListPlugins(dockerCli command.Cli, rootcmd *cobra.Command) ([]Plugin, error
 			continue
 		}
 		c := &candidate{paths[0]}
-		p, err := newPlugin(c, rootcmd, dockerCli.ClientInfo().HasExperimental)
+		p, err := newPlugin(c, rootcmd)
 		if err != nil {
 			return nil, err
 		}
@@ -181,19 +170,12 @@ func PluginRunCommand(dockerCli command.Cli, name string, rootcmd *cobra.Command
 		}
 
 		c := &candidate{path: path}
-		plugin, err := newPlugin(c, rootcmd, dockerCli.ClientInfo().HasExperimental)
+		plugin, err := newPlugin(c, rootcmd)
 		if err != nil {
 			return nil, err
 		}
 		if plugin.Err != nil {
 			// TODO: why are we not returning plugin.Err?
-
-			err := plugin.Err.(*pluginError).Cause()
-			// if an experimental plugin was invoked directly while experimental mode is off
-			// provide a more useful error message than "not found".
-			if err, ok := err.(errPluginRequireExperimental); ok {
-				return nil, err
-			}
 			return nil, errPluginNotFound(name)
 		}
 		cmd := exec.Command(plugin.Path, args...)

cli-plugins/manager/metadata.go

@@ -23,6 +23,6 @@ type Metadata struct {
 	// URL is a pointer to the plugin's homepage.
 	URL string `json:",omitempty"`
 	// Experimental specifies whether the plugin is experimental.
-	// Experimental plugins are not displayed on non-experimental CLIs.
+	// Deprecated: experimental features are now always enabled in the CLI
 	Experimental bool `json:",omitempty"`
 }

cli-plugins/manager/plugin.go

@@ -35,7 +35,7 @@ type Plugin struct {
 // non-recoverable error.
 //
 // nolint: gocyclo
-func newPlugin(c Candidate, rootcmd *cobra.Command, allowExperimental bool) (Plugin, error) {
+func newPlugin(c Candidate, rootcmd *cobra.Command) (Plugin, error) {
 	path := c.Path()
 	if path == "" {
 		return Plugin{}, errors.New("plugin candidate path cannot be empty")
@@ -96,10 +96,6 @@ func newPlugin(c Candidate, rootcmd *cobra.Command, allowExperimental bool) (Plu
 		p.Err = wrapAsPluginError(err, "invalid metadata")
 		return p, nil
 	}
-	if p.Experimental && !allowExperimental {
-		p.Err = &pluginError{errPluginRequireExperimental(p.Name)}
-		return p, nil
-	}
 	if p.Metadata.SchemaVersion != "0.1.0" {
 		p.Err = NewPluginError("plugin SchemaVersion %q is not valid, must be 0.1.0", p.Metadata.SchemaVersion)
 		return p, nil

cli/command/cli.go

@@ -152,16 +152,6 @@ func (cli *DockerCli) ClientInfo() ClientInfo {
 }
 
 func (cli *DockerCli) loadClientInfo() error {
-	var experimentalValue string
-	// Environment variable always overrides configuration
-	if experimentalValue = os.Getenv("DOCKER_CLI_EXPERIMENTAL"); experimentalValue == "" {
-		experimentalValue = cli.ConfigFile().Experimental
-	}
-	hasExperimental, err := isEnabled(experimentalValue)
-	if err != nil {
-		return errors.Wrap(err, "Experimental field")
-	}
-
 	var v string
 	if cli.client != nil {
 		v = cli.client.ClientVersion()
@@ -170,7 +160,7 @@ func (cli *DockerCli) loadClientInfo() error {
 	}
 	cli.clientInfo = &ClientInfo{
 		DefaultVersion:  v,
-		HasExperimental: hasExperimental,
+		HasExperimental: true,
 	}
 	return nil
 }
@@ -358,17 +348,6 @@ func resolveDefaultDockerEndpoint(opts *cliflags.CommonOptions) (docker.Endpoint
 	}, nil
 }
 
-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() {
 	ctx := context.Background()
 	if strings.HasPrefix(cli.DockerEndpoint().Host, "tcp://") {
@@ -471,6 +450,8 @@ type ServerInfo struct {
 
 // ClientInfo stores details about the supported features of the client
 type ClientInfo struct {
+	// Deprecated: experimental CLI features always enabled. This field is kept
+	// for backward-compatibility, and is always "true".
 	HasExperimental bool
 	DefaultVersion  string
 }

cli/command/cli_test.go

@@ -167,25 +167,24 @@ func TestInitializeFromClient(t *testing.T) {
 	}
 }
 
+// The CLI no longer disables/hides experimental CLI features, however, we need
+// to verify that existing configuration files do not break
 func TestExperimentalCLI(t *testing.T) {
 	defaultVersion := "v1.55"
 
 	var testcases = []struct {
-		doc                     string
-		configfile              string
-		expectedExperimentalCLI bool
+		doc        string
+		configfile string
 	}{
 		{
-			doc:                     "default",
-			configfile:              `{}`,
-			expectedExperimentalCLI: false,
+			doc:        "default",
+			configfile: `{}`,
 		},
 		{
 			doc: "experimental",
 			configfile: `{
 	"experimental": "enabled"
 }`,
-			expectedExperimentalCLI: true,
 		},
 	}
 
@@ -205,7 +204,8 @@ func TestExperimentalCLI(t *testing.T) {
 			cliconfig.SetDir(dir.Path())
 			err := cli.Initialize(flags.NewClientOptions())
 			assert.NilError(t, err)
-			assert.Check(t, is.Equal(testcase.expectedExperimentalCLI, cli.ClientInfo().HasExperimental))
+			// For backward-compatibility, HasExperimental will always be "true"
+			assert.Check(t, is.Equal(true, cli.ClientInfo().HasExperimental))
 		})
 	}
 }

cli/command/stack/kubernetes/cli.go

@@ -103,7 +103,7 @@ func WrapCli(dockerCli command.Cli, opts Options) (*KubeCli, error) {
 }
 
 func (c *KubeCli) composeClient() (*Factory, error) {
-	return NewFactory(c.kubeNamespace, c.kubeConfig, c.clientSet, c.ClientInfo().HasExperimental)
+	return NewFactory(c.kubeNamespace, c.kubeConfig, c.clientSet)
 }
 
 func (c *KubeCli) checkHostsMatch() error {

cli/command/stack/kubernetes/client.go

@@ -18,11 +18,10 @@ type Factory struct {
 	coreClientSet corev1.CoreV1Interface
 	appsClientSet appsv1beta2.AppsV1beta2Interface
 	clientSet     *kubeclient.Clientset
-	experimental  bool
 }
 
 // NewFactory creates a kubernetes client factory
-func NewFactory(namespace string, config *restclient.Config, clientSet *kubeclient.Clientset, experimental bool) (*Factory, error) {
+func NewFactory(namespace string, config *restclient.Config, clientSet *kubeclient.Clientset) (*Factory, error) {
 	coreClientSet, err := corev1.NewForConfig(config)
 	if err != nil {
 		return nil, err
@@ -39,7 +38,6 @@ func NewFactory(namespace string, config *restclient.Config, clientSet *kubeclie
 		coreClientSet: coreClientSet,
 		appsClientSet: appsClientSet,
 		clientSet:     clientSet,
-		experimental:  experimental,
 	}, nil
 }
 
@@ -85,7 +83,7 @@ func (s *Factory) DaemonSets() typesappsv1beta2.DaemonSetInterface {
 
 // Stacks returns a client for Docker's Stack on Kubernetes
 func (s *Factory) Stacks(allNamespaces bool) (StackClient, error) {
-	version, err := kubernetes.GetStackAPIVersion(s.clientSet.Discovery(), s.experimental)
+	version, err := kubernetes.GetStackAPIVersion(s.clientSet.Discovery())
 	if err != nil {
 		return nil, err
 	}

cli/command/system/version.go

@@ -2,9 +2,9 @@ package system
 
 import (
 	"context"
-	"fmt"
 	"runtime"
 	"sort"
+	"strconv"
 	"text/tabwriter"
 	"text/template"
 	"time"
@@ -83,7 +83,7 @@ type clientVersion struct {
 	Arch              string
 	BuildTime         string `json:",omitempty"`
 	Context           string
-	Experimental      bool
+	Experimental      bool `json:",omitempty"` // Deprecated: experimental CLI features always enabled. This field is kept for backward-compatibility, and is always "true"
 }
 
 type kubernetesVersion struct {
@@ -157,7 +157,7 @@ func runVersion(dockerCli command.Cli, opts *versionOptions) error {
 			BuildTime:         reformatDate(version.BuildTime),
 			Os:                runtime.GOOS,
 			Arch:              arch(),
-			Experimental:      dockerCli.ClientInfo().HasExperimental,
+			Experimental:      true,
 			Context:           dockerCli.CurrentContext(),
 		},
 	}
@@ -199,7 +199,7 @@ func runVersion(dockerCli command.Cli, opts *versionOptions) error {
 					"Os":            sv.Os,
 					"Arch":          sv.Arch,
 					"BuildTime":     reformatDate(vd.Server.BuildTime),
-					"Experimental":  fmt.Sprintf("%t", sv.Experimental),
+					"Experimental":  strconv.FormatBool(sv.Experimental),
 				},
 			})
 		}
@@ -274,13 +274,13 @@ func getKubernetesVersion(dockerCli command.Cli, kubeConfig string) *kubernetesV
 		logrus.Debugf("failed to get Kubernetes client: %s", err)
 		return &version
 	}
-	version.StackAPI = getStackVersion(kubeClient, dockerCli.ClientInfo().HasExperimental)
+	version.StackAPI = getStackVersion(kubeClient)
 	version.Kubernetes = getKubernetesServerVersion(kubeClient)
 	return &version
 }
 
-func getStackVersion(client *kubernetesClient.Clientset, experimental bool) string {
-	apiVersion, err := kubernetes.GetStackAPIVersion(client, experimental)
+func getStackVersion(client *kubernetesClient.Clientset) string {
+	apiVersion, err := kubernetes.GetStackAPIVersion(client)
 	if err != nil {
 		logrus.Debugf("failed to get Stack API version: %s", err)
 		return "Unknown"

cmd/docker/docker.go

@@ -336,12 +336,11 @@ func hideSubcommandIf(subcmd *cobra.Command, condition func(string) bool, annota
 
 func hideUnsupportedFeatures(cmd *cobra.Command, details versionDetails) error {
 	var (
-		buildKitDisabled   = func(_ string) bool { v, _ := command.BuildKitEnabled(details.ServerInfo()); return !v }
-		buildKitEnabled    = func(_ string) bool { v, _ := command.BuildKitEnabled(details.ServerInfo()); return v }
-		notExperimental    = func(_ string) bool { return !details.ServerInfo().HasExperimental }
-		notExperimentalCLI = func(_ string) bool { return !details.ClientInfo().HasExperimental }
-		notOSType          = func(v string) bool { return v != details.ServerInfo().OSType }
-		versionOlderThan   = func(v string) bool { return versions.LessThan(details.Client().ClientVersion(), v) }
+		buildKitDisabled = func(_ string) bool { v, _ := command.BuildKitEnabled(details.ServerInfo()); return !v }
+		buildKitEnabled  = func(_ string) bool { v, _ := command.BuildKitEnabled(details.ServerInfo()); return v }
+		notExperimental  = func(_ string) bool { return !details.ServerInfo().HasExperimental }
+		notOSType        = func(v string) bool { return v != details.ServerInfo().OSType }
+		versionOlderThan = func(v string) bool { return versions.LessThan(details.Client().ClientVersion(), v) }
 	)
 
 	cmd.Flags().VisitAll(func(f *pflag.Flag) {
@@ -359,7 +358,6 @@ func hideUnsupportedFeatures(cmd *cobra.Command, details versionDetails) error {
 		hideFlagIf(f, buildKitDisabled, "buildkit")
 		hideFlagIf(f, buildKitEnabled, "no-buildkit")
 		hideFlagIf(f, notExperimental, "experimental")
-		hideFlagIf(f, notExperimentalCLI, "experimentalCLI")
 		hideFlagIf(f, notOSType, "ostype")
 		hideFlagIf(f, versionOlderThan, "version")
 	})
@@ -368,7 +366,6 @@ func hideUnsupportedFeatures(cmd *cobra.Command, details versionDetails) error {
 		hideSubcommandIf(subcmd, buildKitDisabled, "buildkit")
 		hideSubcommandIf(subcmd, buildKitEnabled, "no-buildkit")
 		hideSubcommandIf(subcmd, notExperimental, "experimental")
-		hideSubcommandIf(subcmd, notExperimentalCLI, "experimentalCLI")
 		hideSubcommandIf(subcmd, notOSType, "ostype")
 		hideSubcommandIf(subcmd, versionOlderThan, "version")
 	}
@@ -417,9 +414,6 @@ func areFlagsSupported(cmd *cobra.Command, details versionDetails) error {
 		if _, ok := f.Annotations["experimental"]; ok && !details.ServerInfo().HasExperimental {
 			errs = append(errs, fmt.Sprintf(`"--%s" is only supported on a Docker daemon with experimental features enabled`, f.Name))
 		}
-		if _, ok := f.Annotations["experimentalCLI"]; ok && !details.ClientInfo().HasExperimental {
-			errs = append(errs, fmt.Sprintf(`"--%s" is only supported on a Docker cli with experimental cli features enabled`, f.Name))
-		}
 		// buildkit-specific flags are noop when buildkit is not enabled, so we do not add an error in that case
 	})
 	if len(errs) > 0 {
@@ -441,9 +435,6 @@ func areSubcommandsSupported(cmd *cobra.Command, details versionDetails) error {
 		if _, ok := curr.Annotations["experimental"]; ok && !details.ServerInfo().HasExperimental {
 			return fmt.Errorf("%s is only supported on a Docker daemon with experimental features enabled", cmd.CommandPath())
 		}
-		if _, ok := curr.Annotations["experimentalCLI"]; ok && !details.ClientInfo().HasExperimental {
-			return fmt.Errorf("%s is only supported on a Docker cli with experimental cli features enabled", cmd.CommandPath())
-		}
 	}
 	return nil
 }