Provide default SMTP pipeline

default-remote-delivery is no-op for now because we don't have
message queue (https://github.com/emersion/maddy/issues/11).

default.go

@@ -35,4 +35,5 @@ func init() {
 	}
 
 	module.RegisterInstance(mod)
+	module.RegisterInstance(Dummy{instName: "default-remote-delivery"})
 }

maddy.go

@@ -63,15 +63,11 @@ func Start(cfg []config.CfgTreeNode) error {
 }
 
 func authProvider(args []string) (module.AuthProvider, error) {
-	var (
-		authName string
-		ok       bool
-	)
 	if len(args) != 1 {
 		return nil, errors.New("auth: expected 1 argument")
 	}
 
-	authName = args[0]
+	authName := args[0]
 	authMod := module.GetInstance(authName)
 	if authMod == nil {
 		return nil, fmt.Errorf("unknown auth. provider instance: %s", authName)
@@ -85,15 +81,11 @@ func authProvider(args []string) (module.AuthProvider, error) {
 }
 
 func storageBackend(args []string) (module.Storage, error) {
-	var (
-		authName string
-		ok       bool
-	)
 	if len(args) != 1 {
 		return nil, errors.New("storage: expected 1 argument")
 	}
 
-	authName = args[0]
+	authName := args[0]
 	authMod := module.GetInstance(authName)
 	if authMod == nil {
 		return nil, fmt.Errorf("unknown storage backend instance: %s", authName)
@@ -105,3 +97,21 @@ func storageBackend(args []string) (module.Storage, error) {
 	}
 	return provider, nil
 }
+
+func deliveryTarget(args []string) (module.DeliveryTarget, error) {
+	if len(args) != 1 {
+		return nil, errors.New("delivery: expected 1 argument")
+	}
+
+	modName := args[0]
+	mod := module.GetInstance(modName)
+	if mod == nil {
+		return nil, fmt.Errorf("unknown storage backend instance: %s", modName)
+	}
+
+	target, ok := mod.(module.DeliveryTarget)
+	if !ok {
+		return nil, fmt.Errorf("module %s doesn't implements delivery target interface", mod.Name())
+	}
+	return target, nil
+}

smtp.go

@@ -142,6 +142,32 @@ func NewSMTPEndpoint(instName string, cfg config.CfgTreeNode) (module.Module, er
 		}
 	}
 
+	if endp.domain == "" {
+		return nil, fmt.Errorf("hostname is not set")
+	}
+
+	if len(endp.pipeline) == 0 {
+		log.Printf("smtp %s: using default pipeline configuration")
+
+		localDelivery, err := deliveryTarget([]string{"default-local-delivery"})
+		if err != nil {
+			localDelivery, err = deliveryTarget([]string{"default"})
+			if err != nil {
+				return nil, errors.New("missing default local delivery target, must set custom")
+			}
+		}
+
+		remoteDelivery, err := deliveryTarget([]string{"default-remote-delivery"})
+		if err != nil {
+			return nil, errors.New("missing default remote delivery target, must set custom")
+		}
+
+		endp.pipeline = append(endp.pipeline,
+			deliveryStep{t: localDelivery, opts: map[string]string{"local-only": ""}},
+			deliveryStep{t: remoteDelivery, opts: map[string]string{"remote-only": ""}},
+		)
+	}
+
 	if endp.Auth == nil {
 		endp.Auth, err = authProvider([]string{"default-auth"})
 		if err != nil {