Plugable secret backend

This commit extends SwarmKit secret management with pluggable secret
backends support.
Following previous commits:
1. docker/swarmkit@eebac27434
2. docker/docker@08f7cf0526
Added driver parameter to `docker secret` command.

Specifically:

1. `docker secret create [secret_name] --driver [driver_name]`
2.  Displaying the driver in
```
    $ docker secret ls
    $ docker secret inspect [secret_name]
    $ docker secret inspect [secret_name] -pretty
```

Signed-off-by: Liron Levin <liron@twistlock.com>

cli/command/formatter/secret.go

@@ -12,7 +12,7 @@ import (
 )
 
 const (
-	defaultSecretTableFormat           = "table {{.ID}}\t{{.Name}}\t{{.CreatedAt}}\t{{.UpdatedAt}}"
+	defaultSecretTableFormat           = "table {{.ID}}\t{{.Name}}\t{{.Driver}}\t{{.CreatedAt}}\t{{.UpdatedAt}}"
 	secretIDHeader                     = "ID"
 	secretCreatedHeader                = "CREATED"
 	secretUpdatedHeader                = "UPDATED"
@@ -23,6 +23,7 @@ Labels:
 {{- range $k, $v := .Labels }}
  - {{ $k }}{{if $v }}={{ $v }}{{ end }}
 {{- end }}{{ end }}
+Driver:            {{.Driver}}
 Created at:        {{.CreatedAt}}
 Updated at:        {{.UpdatedAt}}`
 )
@@ -61,6 +62,7 @@ func newSecretContext() *secretContext {
 	sCtx.header = map[string]string{
 		"ID":        secretIDHeader,
 		"Name":      nameHeader,
+		"Driver":    driverHeader,
 		"CreatedAt": secretCreatedHeader,
 		"UpdatedAt": secretUpdatedHeader,
 		"Labels":    labelsHeader,
@@ -89,6 +91,13 @@ func (c *secretContext) CreatedAt() string {
 	return units.HumanDuration(time.Now().UTC().Sub(c.s.Meta.CreatedAt)) + " ago"
 }
 
+func (c *secretContext) Driver() string {
+	if c.s.Spec.Driver == nil {
+		return ""
+	}
+	return c.s.Spec.Driver.Name
+}
+
 func (c *secretContext) UpdatedAt() string {
 	return units.HumanDuration(time.Now().UTC().Sub(c.s.Meta.UpdatedAt)) + " ago"
 }
@@ -153,6 +162,13 @@ func (ctx *secretInspectContext) Labels() map[string]string {
 	return ctx.Secret.Spec.Labels
 }
 
+func (ctx *secretInspectContext) Driver() string {
+	if ctx.Secret.Spec.Driver == nil {
+		return ""
+	}
+	return ctx.Secret.Spec.Driver.Name
+}
+
 func (ctx *secretInspectContext) CreatedAt() string {
 	return command.PrettyPrint(ctx.Secret.CreatedAt)
 }

cli/command/formatter/secret_test.go

@@ -28,7 +28,7 @@ func TestSecretContextFormatWrite(t *testing.T) {
 		},
 		// Table format
 		{Context{Format: NewSecretFormat("table", false)},
-			`ID                  NAME                CREATED                  UPDATED
+			`ID                  NAME                DRIVER              CREATED                  UPDATED
 1                   passwords                               Less than a second ago   Less than a second ago
 2                   id_rsa                                  Less than a second ago   Less than a second ago
 `},

cli/command/secret/create.go

@@ -17,6 +17,7 @@ import (
 
 type createOptions struct {
 	name   string
+	driver string
 	file   string
 	labels opts.ListOpts
 }
@@ -27,17 +28,21 @@ func newSecretCreateCommand(dockerCli command.Cli) *cobra.Command {
 	}
 
 	cmd := &cobra.Command{
-		Use:   "create [OPTIONS] SECRET file|-",
+		Use:   "create [OPTIONS] SECRET [file|-]",
 		Short: "Create a secret from a file or STDIN as content",
-		Args:  cli.ExactArgs(2),
+		Args:  cli.RequiresRangeArgs(1, 2),
 		RunE: func(cmd *cobra.Command, args []string) error {
 			options.name = args[0]
+			if len(args) == 2 {
 				options.file = args[1]
+			}
 			return runSecretCreate(dockerCli, options)
 		},
 	}
 	flags := cmd.Flags()
 	flags.VarP(&options.labels, "label", "l", "Secret labels")
+	flags.StringVarP(&options.driver, "driver", "d", "", "Secret driver")
+	flags.SetAnnotation("driver", "version", []string{"1.31"})
 
 	return cmd
 }
@@ -46,21 +51,14 @@ func runSecretCreate(dockerCli command.Cli, options createOptions) error {
 	client := dockerCli.Client()
 	ctx := context.Background()
 
-	var in io.Reader = dockerCli.In()
+	if options.driver != "" && options.file != "" {
-	if options.file != "-" {
+		return errors.Errorf("When using secret driver secret data must be empty")
-		file, err := system.OpenSequential(options.file)
-		if err != nil {
-			return err
-		}
-		in = file
-		defer file.Close()
 	}
 
-	secretData, err := ioutil.ReadAll(in)
+	secretData, err := readSecretData(dockerCli.In(), options.file)
 	if err != nil {
 		return errors.Errorf("Error reading content from %q: %v", options.file, err)
 	}
-
 	spec := swarm.SecretSpec{
 		Annotations: swarm.Annotations{
 			Name:   options.name,
@@ -68,6 +66,11 @@ func runSecretCreate(dockerCli command.Cli, options createOptions) error {
 		},
 		Data: secretData,
 	}
+	if options.driver != "" {
+		spec.Driver = &swarm.Driver{
+			Name: options.driver,
+		}
+	}
 
 	r, err := client.SecretCreate(ctx, spec)
 	if err != nil {
@@ -77,3 +80,23 @@ func runSecretCreate(dockerCli command.Cli, options createOptions) error {
 	fmt.Fprintln(dockerCli.Out(), r.ID)
 	return nil
 }
+
+func readSecretData(in io.ReadCloser, file string) ([]byte, error) {
+	// Read secret value from external driver
+	if file == "" {
+		return nil, nil
+	}
+	if file != "-" {
+		var err error
+		in, err = system.OpenSequential(file)
+		if err != nil {
+			return nil, err
+		}
+		defer in.Close()
+	}
+	data, err := ioutil.ReadAll(in)
+	if err != nil {
+		return nil, err
+	}
+	return data, nil
+}

cli/command/secret/create_test.go

@@ -24,12 +24,11 @@ func TestSecretCreateErrors(t *testing.T) {
 		secretCreateFunc func(swarm.SecretSpec) (types.SecretCreateResponse, error)
 		expectedError    string
 	}{
-		{
-			args:          []string{"too_few"},
-			expectedError: "requires exactly 2 arguments",
-		},
 		{args: []string{"too", "many", "arguments"},
-			expectedError: "requires exactly 2 arguments",
+			expectedError: "requires at least 1 and at most 2 arguments",
+		},
+		{args: []string{"create", "--driver", "driver", "-"},
+			expectedError: "secret data must be empty",
 		},
 		{
 			args: []string{"name", filepath.Join("testdata", secretDataFile)},
@@ -75,6 +74,35 @@ func TestSecretCreateWithName(t *testing.T) {
 	assert.Equal(t, "ID-"+name, strings.TrimSpace(cli.OutBuffer().String()))
 }
 
+func TestSecretCreateWithDriver(t *testing.T) {
+	expectedDriver := &swarm.Driver{
+		Name: "secret-driver",
+	}
+	name := "foo"
+
+	cli := test.NewFakeCli(&fakeClient{
+		secretCreateFunc: func(spec swarm.SecretSpec) (types.SecretCreateResponse, error) {
+			if spec.Name != name {
+				return types.SecretCreateResponse{}, errors.Errorf("expected name %q, got %q", name, spec.Name)
+			}
+
+			if !reflect.DeepEqual(spec.Driver.Name, expectedDriver.Name) {
+				return types.SecretCreateResponse{}, errors.Errorf("expected driver %v, got %v", expectedDriver, spec.Labels)
+			}
+
+			return types.SecretCreateResponse{
+				ID: "ID-" + spec.Name,
+			}, nil
+		},
+	})
+
+	cmd := newSecretCreateCommand(cli)
+	cmd.SetArgs([]string{name})
+	cmd.Flags().Set("driver", expectedDriver.Name)
+	assert.NoError(t, cmd.Execute())
+	assert.Equal(t, "ID-"+name, strings.TrimSpace(cli.OutBuffer().String()))
+}
+
 func TestSecretCreateWithLabels(t *testing.T) {
 	expectedLabels := map[string]string{
 		"lbl1": "Label-foo",

cli/command/secret/inspect_test.go

@@ -154,6 +154,7 @@ func TestSecretInspectPretty(t *testing.T) {
 					}),
 					SecretID("secretID"),
 					SecretName("secretName"),
+					SecretDriver("driver"),
 					SecretCreatedAt(time.Time{}),
 					SecretUpdatedAt(time.Time{}),
 				), []byte{}, nil

cli/command/secret/ls_test.go

@@ -63,6 +63,7 @@ func TestSecretList(t *testing.T) {
 					SecretVersion(swarm.Version{Index: 11}),
 					SecretCreatedAt(time.Now().Add(-2*time.Hour)),
 					SecretUpdatedAt(time.Now().Add(-1*time.Hour)),
+					SecretDriver("driver"),
 				),
 			}, nil
 		},

cli/command/secret/testdata/secret-inspect-pretty.simple.golden

@@ -2,5 +2,6 @@ ID:			secretID
 Name:              secretName
 Labels:
  - lbl1=value1
+Driver:            driver
 Created at:        0001-01-01 00:00:00 +0000 utc
 Updated at:        0001-01-01 00:00:00 +0000 utc

cli/command/secret/testdata/secret-list-with-filter.golden

@@ -1,3 +1,3 @@
-ID                  NAME                CREATED             UPDATED
+ID                  NAME                DRIVER              CREATED             UPDATED
 ID-foo              foo                                     2 hours ago         About an hour ago
 ID-bar              bar                                     2 hours ago         About an hour ago

cli/command/secret/testdata/secret-list.golden

@@ -1,3 +1,3 @@
-ID                  NAME                CREATED             UPDATED
+ID                  NAME                DRIVER              CREATED             UPDATED
 ID-foo              foo                                     2 hours ago         About an hour ago
-ID-bar              bar                 2 hours ago         About an hour ago
+ID-bar              bar                 driver              2 hours ago         About an hour ago

internal/test/builders/secret.go

@@ -32,6 +32,15 @@ func SecretName(name string) func(secret *swarm.Secret) {
 	}
 }
 
+// SecretDriver sets the secret's driver name
+func SecretDriver(driver string) func(secret *swarm.Secret) {
+	return func(secret *swarm.Secret) {
+		secret.Spec.Driver = &swarm.Driver{
+			Name: driver,
+		}
+	}
+}
+
 // SecretID sets the secret's ID
 func SecretID(ID string) func(secret *swarm.Secret) {
 	return func(secret *swarm.Secret) {