Enforce zero plugin refcount during disable.

When plugins have a positive refcount, they were not allowed to be
removed. However, plugins could still be disabled when volumes
referenced it and containers using them were running.

This change fixes that by enforcing plugin refcount during disable.
A "force" disable option is also added to ignore reference refcounting.

Signed-off-by: Anusha Ragunathan <anusha@docker.com>

api/server/router/plugin/backend.go

@@ -10,7 +10,7 @@ import (
 
 // Backend for Plugin
 type Backend interface {
-	Disable(name string) error
+	Disable(name string, config *enginetypes.PluginDisableConfig) error
 	Enable(name string, config *enginetypes.PluginEnableConfig) error
 	List() ([]enginetypes.Plugin, error)
 	Inspect(name string) (enginetypes.Plugin, error)

api/server/router/plugin/plugin_routes.go

@@ -99,7 +99,16 @@ func (pr *pluginRouter) enablePlugin(ctx context.Context, w http.ResponseWriter,
 }
 
 func (pr *pluginRouter) disablePlugin(ctx context.Context, w http.ResponseWriter, r *http.Request, vars map[string]string) error {
-	return pr.backend.Disable(vars["name"])
+	if err := httputils.ParseForm(r); err != nil {
+		return err
+	}
+
+	name := vars["name"]
+	config := &types.PluginDisableConfig{
+		ForceDisable: httputils.BoolValue(r, "force"),
+	}
+
+	return pr.backend.Disable(name, config)
 }
 
 func (pr *pluginRouter) removePlugin(ctx context.Context, w http.ResponseWriter, r *http.Request, vars map[string]string) error {

api/types/client.go

@@ -340,6 +340,11 @@ type PluginEnableOptions struct {
 	Timeout int
 }
 
+// PluginDisableOptions holds parameters to disable plugins.
+type PluginDisableOptions struct {
+	Force bool
+}
+
 // PluginInstallOptions holds parameters to install a plugin.
 type PluginInstallOptions struct {
 	Disabled              bool

api/types/configs.go

@@ -53,14 +53,17 @@ type ExecConfig struct {
 	Cmd          []string // Execution commands and args
 }
 
-// PluginRmConfig holds arguments for the plugin remove
+// PluginRmConfig holds arguments for plugin remove.
-// operation. This struct is used to tell the backend what operations
-// to perform.
 type PluginRmConfig struct {
 	ForceRemove bool
 }
 
-// PluginEnableConfig holds arguments for the plugin enable
+// PluginEnableConfig holds arguments for plugin enable
 type PluginEnableConfig struct {
 	Timeout int
 }
+
+// PluginDisableConfig holds arguments for plugin disable.
+type PluginDisableConfig struct {
+	ForceDisable bool
+}

cli/command/plugin/disable.go

@@ -3,6 +3,7 @@ package plugin
 import (
 	"fmt"
 
+	"github.com/docker/docker/api/types"
 	"github.com/docker/docker/cli"
 	"github.com/docker/docker/cli/command"
 	"github.com/docker/docker/reference"
@@ -11,19 +12,23 @@ import (
 )
 
 func newDisableCommand(dockerCli *command.DockerCli) *cobra.Command {
+	var force bool
+
 	cmd := &cobra.Command{
 		Use:   "disable PLUGIN",
 		Short: "Disable a plugin",
 		Args:  cli.ExactArgs(1),
 		RunE: func(cmd *cobra.Command, args []string) error {
-			return runDisable(dockerCli, args[0])
+			return runDisable(dockerCli, args[0], force)
 		},
 	}
 
+	flags := cmd.Flags()
+	flags.BoolVarP(&force, "force", "f", false, "Force the disable of an active plugin")
 	return cmd
 }
 
-func runDisable(dockerCli *command.DockerCli, name string) error {
+func runDisable(dockerCli *command.DockerCli, name string, force bool) error {
 	named, err := reference.ParseNamed(name) // FIXME: validate
 	if err != nil {
 		return err
@@ -35,7 +40,7 @@ func runDisable(dockerCli *command.DockerCli, name string) error {
 	if !ok {
 		return fmt.Errorf("invalid name: %s", named.String())
 	}
-	if err := dockerCli.Client().PluginDisable(context.Background(), ref.String()); err != nil {
+	if err := dockerCli.Client().PluginDisable(context.Background(), ref.String(), types.PluginDisableOptions{Force: force}); err != nil {
 		return err
 	}
 	fmt.Fprintln(dockerCli.Out(), name)

client/interface.go

@@ -110,7 +110,7 @@ type PluginAPIClient interface {
 	PluginList(ctx context.Context) (types.PluginsListResponse, error)
 	PluginRemove(ctx context.Context, name string, options types.PluginRemoveOptions) error
 	PluginEnable(ctx context.Context, name string, options types.PluginEnableOptions) error
-	PluginDisable(ctx context.Context, name string) error
+	PluginDisable(ctx context.Context, name string, options types.PluginDisableOptions) error
 	PluginInstall(ctx context.Context, name string, options types.PluginInstallOptions) error
 	PluginPush(ctx context.Context, name string, registryAuth string) error
 	PluginSet(ctx context.Context, name string, args []string) error

client/plugin_disable.go

@@ -1,12 +1,19 @@
 package client
 
 import (
+	"net/url"
+
+	"github.com/docker/docker/api/types"
 	"golang.org/x/net/context"
 )
 
 // PluginDisable disables a plugin
-func (cli *Client) PluginDisable(ctx context.Context, name string) error {
+func (cli *Client) PluginDisable(ctx context.Context, name string, options types.PluginDisableOptions) error {
-	resp, err := cli.post(ctx, "/plugins/"+name+"/disable", nil, nil, nil)
+	query := url.Values{}
+	if options.Force {
+		query.Set("force", "1")
+	}
+	resp, err := cli.post(ctx, "/plugins/"+name+"/disable", query, nil, nil)
 	ensureReaderClosed(resp)
 	return err
 }

client/plugin_disable_test.go

@@ -8,6 +8,7 @@ import (
 	"strings"
 	"testing"
 
+	"github.com/docker/docker/api/types"
 	"golang.org/x/net/context"
 )
 
@@ -16,7 +17,7 @@ func TestPluginDisableError(t *testing.T) {
 		client: newMockClient(errorMock(http.StatusInternalServerError, "Server error")),
 	}
 
-	err := client.PluginDisable(context.Background(), "plugin_name")
+	err := client.PluginDisable(context.Background(), "plugin_name", types.PluginDisableOptions{})
 	if err == nil || err.Error() != "Error response from daemon: Server error" {
 		t.Fatalf("expected a Server Error, got %v", err)
 	}
@@ -40,7 +41,7 @@ func TestPluginDisable(t *testing.T) {
 		}),
 	}
 
-	err := client.PluginDisable(context.Background(), "plugin_name")
+	err := client.PluginDisable(context.Background(), "plugin_name", types.PluginDisableOptions{})
 	if err != nil {
 		t.Fatal(err)
 	}

docs/reference/commandline/plugin_disable.md

@@ -21,11 +21,13 @@ Usage:  docker plugin disable PLUGIN
 Disable a plugin
 
 Options:
+  -f, --force   Force the disable of an active plugin
       --help    Print usage
 ```
 
 Disables a plugin. The plugin must be installed before it can be disabled,
-see [`docker plugin install`](plugin_install.md).
+see [`docker plugin install`](plugin_install.md). Without the `-f` option,
+a plugin that has references (eg, volumes, networks) cannot be disabled.
 
 
 The following example shows that the `no-remove` plugin is installed

integration-cli/docker_cli_daemon_plugins_test.go

@@ -268,10 +268,17 @@ func (s *DockerDaemonSuite) TestPluginVolumeRemoveOnRestart(c *check.C) {
 	s.d.Restart(c, "--live-restore=true")
 
 	out, err = s.d.Cmd("plugin", "disable", pName)
-	c.Assert(err, checker.IsNil, check.Commentf(out))
-	out, err = s.d.Cmd("plugin", "rm", pName)
 	c.Assert(err, checker.NotNil, check.Commentf(out))
 	c.Assert(out, checker.Contains, "in use")
+
+	out, err = s.d.Cmd("volume", "rm", "test")
+	c.Assert(err, checker.IsNil, check.Commentf(out))
+
+	out, err = s.d.Cmd("plugin", "disable", pName)
+	c.Assert(err, checker.IsNil, check.Commentf(out))
+
+	out, err = s.d.Cmd("plugin", "rm", pName)
+	c.Assert(err, checker.IsNil, check.Commentf(out))
 }
 
 func existsMountpointWithPrefix(mountpointPrefix string) (bool, error) {

integration-cli/docker_cli_plugins_test.go

@@ -64,23 +64,18 @@ func (s *DockerSuite) TestPluginForceRemove(c *check.C) {
 
 func (s *DockerSuite) TestPluginActive(c *check.C) {
 	testRequires(c, DaemonIsLinux, IsAmd64, Network)
-	out, _, err := dockerCmdWithError("plugin", "install", "--grant-all-permissions", pNameWithTag)
+	_, _, err := dockerCmdWithError("plugin", "install", "--grant-all-permissions", pNameWithTag)
 	c.Assert(err, checker.IsNil)
 
-	out, _, err = dockerCmdWithError("volume", "create", "-d", pNameWithTag)
+	_, _, err = dockerCmdWithError("volume", "create", "-d", pNameWithTag, "--name", "testvol1")
 	c.Assert(err, checker.IsNil)
 
-	vID := strings.TrimSpace(out)
+	out, _, err := dockerCmdWithError("plugin", "disable", pNameWithTag)
+	c.Assert(out, checker.Contains, "in use")
 
-	out, _, err = dockerCmdWithError("plugin", "remove", pNameWithTag)
+	_, _, err = dockerCmdWithError("volume", "rm", "testvol1")
-	c.Assert(out, checker.Contains, "is in use")
-
-	_, _, err = dockerCmdWithError("volume", "rm", vID)
 	c.Assert(err, checker.IsNil)
 
-	out, _, err = dockerCmdWithError("plugin", "remove", pNameWithTag)
-	c.Assert(out, checker.Contains, "is enabled")
-
 	_, _, err = dockerCmdWithError("plugin", "disable", pNameWithTag)
 	c.Assert(err, checker.IsNil)
 

plugin/backend_linux.go

@@ -31,8 +31,8 @@ var (
 	validPartialID = regexp.MustCompile(`^([a-f0-9]{1,64})$`)
 )
 
-// Disable deactivates a plugin, which implies that they cannot be used by containers.
+// Disable deactivates a plugin. This means resources (volumes, networks) cant use them.
-func (pm *Manager) Disable(name string) error {
+func (pm *Manager) Disable(name string, config *types.PluginDisableConfig) error {
 	p, err := pm.pluginStore.GetByName(name)
 	if err != nil {
 		return err
@@ -41,6 +41,10 @@ func (pm *Manager) Disable(name string) error {
 	c := pm.cMap[p]
 	pm.mu.RUnlock()
 
+	if !config.ForceDisable && p.GetRefCount() > 0 {
+		return fmt.Errorf("plugin %s is in use", p.Name())
+	}
+
 	if err := pm.disable(p, c); err != nil {
 		return err
 	}

plugin/backend_unsupported.go

@@ -15,7 +15,7 @@ import (
 var errNotSupported = errors.New("plugins are not supported on this platform")
 
 // Disable deactivates a plugin, which implies that they cannot be used by containers.
-func (pm *Manager) Disable(name string) error {
+func (pm *Manager) Disable(name string, config *types.PluginDisableConfig) error {
 	return errNotSupported
 }