ignite · ilgooz · Jul 6, 2021 · Jun 17, 2021 · Jun 17, 2021 · Jun 17, 2021
diff --git a/changelog.md b/changelog.md
@@ -9,6 +9,7 @@
 - Added the flag `--no-default-module` to the command `starport app` to prevent scaffolding a default module when creating a new app
 - Added support for multiple naming conventions for component names and field names
 - Print created and modified files when scaffolding a new component
+- Scaffold a type that contains a single instance in the store
 - Introduce `starport tools` command for advanced users. Existing `starport relayer lowlevel *` commands are also moved under `tools`.
 - Added `faucet.rate_limit_window` property to `config.yml`
 

diff --git a/integration/cmd_type_test.go b/integration/cmd_type_test.go
@@ -182,3 +182,55 @@ func TestCreateMapWithStargate(t *testing.T) {
 
 	env.EnsureAppIsSteady(path)
 }
+
+func TestCreateSingletonTypeWithStargate(t *testing.T) {
+	var (
+		env  = newEnv(t)
+		path = env.Scaffold("blog")
+	)
+
+	env.Must(env.Exec("create an singleton type",
+		step.NewSteps(step.New(
+			step.Exec("starport", "s", "single", "user", "email"),
+			step.Workdir(path),
+		)),
+	))
+
+	env.Must(env.Exec("create an singleton type with no message",
+		step.NewSteps(step.New(
+			step.Exec("starport", "s", "single", "no-message", "email", "--no-message"),
+			step.Workdir(path),
+		)),
+	))
+
+	env.Must(env.Exec("create a module",
+		step.NewSteps(step.New(
+			step.Exec("starport", "s", "module", "example", "--require-registration"),
+			step.Workdir(path),
+		)),
+	))
+
+	env.Must(env.Exec("create another type",
+		step.NewSteps(step.New(
+			step.Exec("starport", "s", "list", "user", "email", "--module", "example"),
+			step.Workdir(path),
+		)),
+	))
+
+	env.Must(env.Exec("should prevent creating an singleton type with a typename that already exist",
+		step.NewSteps(step.New(
+			step.Exec("starport", "s", "single", "user", "email", "--module", "example"),
+			step.Workdir(path),
+		)),
+		ExecShouldError(),
+	))
+
+	env.Must(env.Exec("create an singleton type in a custom module",
+		step.NewSteps(step.New(
+			step.Exec("starport", "s", "single", "singleuser", "email", "--module", "example"),
+			step.Workdir(path),
+		)),
+	))
+
+	env.EnsureAppIsSteady(path)
+}
diff --git a/starport/cmd/scaffold.go b/starport/cmd/scaffold.go
@@ -10,6 +10,14 @@ import (
 	"github.com/tendermint/starport/starport/services/scaffolder"
 )
 
+// flags related to component scaffolding
+const (
+	flagModule      = "module"
+	flagNoMessage   = "no-message"
+	flagResponse    = "response"
+	flagDescription = "desc"
+)
+
 // NewScaffold returns a command that groups scaffolding related sub commands.
 func NewScaffold() *cobra.Command {
 	c := &cobra.Command{
@@ -23,6 +31,7 @@ func NewScaffold() *cobra.Command {
 	c.AddCommand(NewScaffoldModule())
 	c.AddCommand(NewScaffoldList())
 	c.AddCommand(NewScaffoldMap())
+	c.AddCommand(NewScaffoldSingle())
 	c.AddCommand(NewScaffoldMessage())
 	c.AddCommand(NewScaffoldQuery())
 	c.AddCommand(NewScaffoldPacket())
@@ -32,7 +41,7 @@ func NewScaffold() *cobra.Command {
 	return c
 }
 
-func scaffoldType(kind, module, typeName string, typeFields []string, opts scaffolder.AddTypeOption) error {
+func scaffoldType(module, typeName string, typeFields []string, opts scaffolder.AddTypeOption) error {
 	s := clispinner.New().SetText("Scaffolding...")
 	defer s.Stop()
 
@@ -48,7 +57,7 @@ func scaffoldType(kind, module, typeName string, typeFields []string, opts scaff
 	s.Stop()
 
 	fmt.Println(sourceModificationToString(sm))
-	fmt.Printf("\n🎉 Created a %s `%s`.\n\n", kind, typeName)
+	fmt.Printf("\n🎉 Created a %s `%s`.\n\n", opts.Model, typeName)
 
 	return nil
 }

diff --git a/starport/cmd/scaffold_list.go b/starport/cmd/scaffold_list.go
@@ -23,7 +23,8 @@ func NewScaffoldList() *cobra.Command {
 func scaffoldListHandler(cmd *cobra.Command, args []string) error {
 	opts := scaffolder.AddTypeOption{
 		NoMessage: flagGetNoMessage(cmd),
+		Model:     scaffolder.List,
 	}
 
-	return scaffoldType("list", flagGetModule(cmd), args[0], args[1:], opts)
+	return scaffoldType(flagGetModule(cmd), args[0], args[1:], opts)
 }
diff --git a/starport/cmd/scaffold_map.go b/starport/cmd/scaffold_map.go
@@ -5,11 +5,6 @@ import (
 	"github.com/tendermint/starport/starport/services/scaffolder"
 )
 
-const (
-	flagModule    = "module"
-	flagNoMessage = "no-message"
-)
-
 // NewScaffoldMap returns a new command to scaffold a map.
 func NewScaffoldMap() *cobra.Command {
 	c := &cobra.Command{
@@ -27,9 +22,9 @@ func NewScaffoldMap() *cobra.Command {
 
 func scaffoldMapHandler(cmd *cobra.Command, args []string) error {
 	opts := scaffolder.AddTypeOption{
-		Indexed:   true,
 		NoMessage: flagGetNoMessage(cmd),
+		Model:     scaffolder.Map,
 	}
 
-	return scaffoldType("map", flagGetModule(cmd), args[0], args[1:], opts)
+	return scaffoldType(flagGetModule(cmd), args[0], args[1:], opts)
 }
diff --git a/starport/cmd/scaffold_message.go b/starport/cmd/scaffold_message.go
@@ -9,11 +9,6 @@ import (
 	"github.com/tendermint/starport/starport/services/scaffolder"
 )
 
-const (
-	flagResponse    string = "response"
-	flagDescription string = "desc"
-)
-
 // NewScaffoldMessage returns the command to scaffold messages
 func NewScaffoldMessage() *cobra.Command {
 	c := &cobra.Command{

diff --git a/starport/cmd/scaffold_single.go b/starport/cmd/scaffold_single.go
@@ -0,0 +1,30 @@
+package starportcmd
+
+import (
+	"github.com/spf13/cobra"
+	"github.com/tendermint/starport/starport/services/scaffolder"
+)
+
+// NewScaffoldSingle returns a new command to scaffold a singleton.
+func NewScaffoldSingle() *cobra.Command {
+	c := &cobra.Command{
+		Use:   "single NAME [field]...",
+		Short: "Scaffold a singleton",
+		Args:  cobra.MinimumNArgs(1),
+		RunE:  scaffoldSingleHandler,
+	}
+
+	c.Flags().StringVarP(&appPath, "path", "p", "", "path of the app")
+	c.Flags().AddFlagSet(flagSetScaffoldType())
+
+	return c
+}
+
+func scaffoldSingleHandler(cmd *cobra.Command, args []string) error {
+	opts := scaffolder.AddTypeOption{
+		NoMessage: flagGetNoMessage(cmd),
+		Model:     scaffolder.Singleton,
+	}
+
+	return scaffoldType(flagGetModule(cmd), args[0], args[1:], opts)
+}
diff --git a/starport/services/scaffolder/type.go b/starport/services/scaffolder/type.go
@@ -1,6 +1,7 @@
 package scaffolder
 
 import (
+	"errors"
 	"fmt"
 	"os"
 
@@ -13,10 +14,19 @@ import (
 	modulecreate "github.com/tendermint/starport/starport/templates/module/create"
 	"github.com/tendermint/starport/starport/templates/typed"
 	"github.com/tendermint/starport/starport/templates/typed/indexed"
+	"github.com/tendermint/starport/starport/templates/typed/singleton"
+)
+
+type TypeModel string
+
+const (
+	List      TypeModel = "list"
+	Map       TypeModel = "map"
+	Singleton TypeModel = "singleton"
 )
 
 type AddTypeOption struct {
-	Indexed   bool
+	Model     TypeModel
 	NoMessage bool
 }
 
@@ -89,16 +99,23 @@ func (s *Scaffolder) AddType(
 		gens = append(gens, g)
 	}
 
-	// Check if indexed type
-	if addTypeOptions.Indexed {
-		g, err = indexed.NewStargate(tracer, opts)
-	} else {
-		// Scaffolding a type with ID
+	// create the type generator depending on the model
+	// TODO: rename the template packages to make it consistent with the type new naming
+	switch addTypeOptions.Model {
+	case List:
 		g, err = typed.NewStargate(tracer, opts)
+	case Map:
+		g, err = indexed.NewStargate(tracer, opts)
+	case Singleton:
+		g, err = singleton.NewStargate(tracer, opts)
+	default:
+		return sm, errors.New("unrecognized type model")
 	}
 	if err != nil {
 		return sm, err
 	}
+
+	// run the generation
 	gens = append(gens, g)
 	sm, err = xgenny.RunWithValidation(tracer, gens...)
 	if err != nil {

diff --git a/.../templates/typed/indexed/stargate/component/x/{{moduleName}}/keeper/{{typeName}}.go.plush b/.../templates/typed/indexed/stargate/component/x/{{moduleName}}/keeper/{{typeName}}.go.plush
@@ -26,7 +26,7 @@ func (k Keeper) Get<%= TypeName.UpperCamel %>(ctx sdk.Context, index string) (va
 	return val, true
 }
 
-// Delete<%= TypeName.UpperCamel %> removes a <%= TypeName.LowerCamel %> from the store
+// Remove<%= TypeName.UpperCamel %> removes a <%= TypeName.LowerCamel %> from the store
 func (k Keeper) Remove<%= TypeName.UpperCamel %>(ctx sdk.Context, index string) {
 	store := prefix.NewStore(ctx.KVStore(k.storeKey), types.KeyPrefix(types.<%= TypeName.UpperCamel %>Key))
 	store.Delete(types.KeyPrefix(index))