add basic mqtt client

go.mod

@@ -3,6 +3,13 @@ module github.com/jwetzell/showbridge-go
 go 1.25.1
 
 require (
+	github.com/eclipse/paho.mqtt.golang v1.5.1
 	github.com/jwetzell/osc-go v0.0.0-20251114203632-24077a77d6c7
 	github.com/urfave/cli/v3 v3.6.0
 )
+
+require (
+	github.com/gorilla/websocket v1.5.3 // indirect
+	golang.org/x/net v0.44.0 // indirect
+	golang.org/x/sync v0.17.0 // indirect
+)

go.sum

@@ -1,5 +1,9 @@
 github.com/davecgh/go-spew v1.1.1 h1:vj9j/u1bqnvCEfJOwUhtlOARqs3+rkHYY13jYWTU97c=
 github.com/davecgh/go-spew v1.1.1/go.mod h1:J7Y8YcW2NihsgmVo/mv3lAwl/skON4iLHjSsI+c5H38=
+github.com/eclipse/paho.mqtt.golang v1.5.1 h1:/VSOv3oDLlpqR2Epjn1Q7b2bSTplJIeV2ISgCl2W7nE=
+github.com/eclipse/paho.mqtt.golang v1.5.1/go.mod h1:1/yJCneuyOoCOzKSsOTUc0AJfpsItBGWvYpBLimhArU=
+github.com/gorilla/websocket v1.5.3 h1:saDtZ6Pbx/0u+bgYQ3q96pZgCzfhKXGPqt7kZ72aNNg=
+github.com/gorilla/websocket v1.5.3/go.mod h1:YR8l580nyteQvAITg2hZ9XVh4b55+EU/adAjf1fMHhE=
 github.com/jwetzell/osc-go v0.0.0-20251114203632-24077a77d6c7 h1:vR4ooQd95vO8pdCugY0Kg7/MSKvuJc0pkHUZlLf6AtM=
 github.com/jwetzell/osc-go v0.0.0-20251114203632-24077a77d6c7/go.mod h1:mkPoLU72wmg9Wq6mh5P5RjsWFXqaUqq4n64EWqg121A=
 github.com/pmezard/go-difflib v1.0.0 h1:4DBwDE0NGyQoBHbLQYPwSUPoCMWR5BEzIk/f1lZbAQM=
@@ -8,5 +12,9 @@ github.com/stretchr/testify v1.11.1 h1:7s2iGBzp5EwR7/aIZr8ao5+dra3wiQyKjjFuvgVKu
 github.com/stretchr/testify v1.11.1/go.mod h1:wZwfW3scLgRK+23gO65QZefKpKQRnfz6sD981Nm4B6U=
 github.com/urfave/cli/v3 v3.6.0 h1:oIdArVjkdIXHWg3iqxgmqwQGC8NM0JtdgwQAj2sRwFo=
 github.com/urfave/cli/v3 v3.6.0/go.mod h1:ysVLtOEmg2tOy6PknnYVhDoouyC/6N42TMeoMzskhso=
+golang.org/x/net v0.44.0 h1:evd8IRDyfNBMBTTY5XRF1vaZlD+EmWx6x8PkhR04H/I=
+golang.org/x/net v0.44.0/go.mod h1:ECOoLqd5U3Lhyeyo/QDCEVQ4sNgYsqvCZ722XogGieY=
+golang.org/x/sync v0.17.0 h1:l60nONMj9l5drqw6jlhIELNv9I0A4OFgRsG9k2oT9Ug=
+golang.org/x/sync v0.17.0/go.mod h1:9KTHXmSnoGruLpwFjVSX0lNNA75CykiMECbovNTZqGI=
 gopkg.in/yaml.v3 v3.0.1 h1:fxVm/GzAzEWqLHuvctI91KS9hhNmmWOoWu0XTYJS7CA=
 gopkg.in/yaml.v3 v3.0.1/go.mod h1:K4uyk7z7BCEPqu6E+C64Yfv1cQ7kz7rIZviUmN+EgEM=

internal/processing/mqtt-message-encode.go

@@ -0,0 +1,35 @@
+package processing
+
+import (
+	"context"
+	"fmt"
+
+	mqtt "github.com/eclipse/paho.mqtt.golang"
+)
+
+type MQTTMessageEncode struct {
+	config ProcessorConfig
+}
+
+func (mme *MQTTMessageEncode) Process(ctx context.Context, payload any) (any, error) {
+	payloadMessage, ok := payload.(mqtt.Message)
+
+	if !ok {
+		return nil, fmt.Errorf("mqtt.message.encode processor only accepts an mqtt.Message")
+	}
+
+	return payloadMessage.Payload(), nil
+}
+
+func (mme *MQTTMessageEncode) Type() string {
+	return mme.config.Type
+}
+
+func init() {
+	RegisterProcessor(ProcessorRegistration{
+		Type: "mqtt.message.encode",
+		New: func(config ProcessorConfig) (Processor, error) {
+			return &MQTTMessageEncode{config: config}, nil
+		},
+	})
+}

mqtt-client.go

@@ -0,0 +1,108 @@
+package showbridge
+
+import (
+	"fmt"
+	"log/slog"
+
+	mqtt "github.com/eclipse/paho.mqtt.golang"
+)
+
+type MQTTClient struct {
+	config   ModuleConfig
+	router   *Router
+	Broker   string
+	ClientID string
+	Topic    string
+	client   mqtt.Client
+}
+
+func init() {
+	RegisterModule(ModuleRegistration{
+		Type: "net.mqtt.client",
+		New: func(config ModuleConfig) (Module, error) {
+			params := config.Params
+			broker, ok := params["broker"]
+
+			if !ok {
+				return nil, fmt.Errorf("net.mqtt.client requires a broker parameter")
+			}
+
+			brokerString, ok := broker.(string)
+
+			if !ok {
+				return nil, fmt.Errorf("net.mqtt.client host must be string")
+			}
+
+			topic, ok := params["topic"]
+
+			if !ok {
+				return nil, fmt.Errorf("net.mqtt.client requires a topic parameter")
+			}
+
+			topicString, ok := topic.(string)
+
+			if !ok {
+				return nil, fmt.Errorf("net.mqtt.client host must be string")
+			}
+
+			clientId, ok := params["clientId"]
+
+			if !ok {
+				return nil, fmt.Errorf("net.mqtt.client requires a clientId parameter")
+			}
+
+			clientIdString, ok := clientId.(string)
+
+			if !ok {
+				return nil, fmt.Errorf("net.mqtt.client host must be string")
+			}
+
+			return &MQTTClient{config: config, Broker: brokerString, Topic: topicString, ClientID: clientIdString}, nil
+		},
+	})
+}
+
+func (mc *MQTTClient) Id() string {
+	return mc.config.Id
+}
+
+func (mc *MQTTClient) Type() string {
+	return mc.config.Type
+}
+
+func (mc *MQTTClient) RegisterRouter(router *Router) {
+	mc.router = router
+}
+
+func (mc *MQTTClient) Run() error {
+	opts := mqtt.NewClientOptions()
+	opts.AddBroker(mc.Broker)
+	opts.SetClientID(mc.ClientID)
+	opts.SetAutoReconnect(true)
+	opts.SetCleanSession(false)
+
+	opts.OnConnect = func(c mqtt.Client) {
+		token := mc.client.Subscribe(mc.Topic, 1, func(c mqtt.Client, m mqtt.Message) {
+			mc.router.HandleInput(mc.config.Id, m)
+		})
+		token.Wait()
+	}
+
+	mc.client = mqtt.NewClient(opts)
+
+	token := mc.client.Connect()
+
+	token.Wait()
+	err := token.Error()
+	if err != nil {
+		return err
+	}
+
+	<-mc.router.Context.Done()
+	slog.Debug("router context done in module", "id", mc.config.Id)
+	return nil
+}
+
+func (mc *MQTTClient) Output(payload any) error {
+	return fmt.Errorf("net.mqtt.client output is not implemented")
+}