initial

go.mod

@@ -0,0 +1,14 @@
+module hottis.de/universal-data-ingest
+
+go 1.21.3
+
+require (
+	github.com/eclipse/paho.mqtt.golang v1.4.3
+	github.com/google/uuid v1.4.0
+)
+
+require (
+	github.com/gorilla/websocket v1.5.0 // indirect
+	golang.org/x/net v0.8.0 // indirect
+	golang.org/x/sync v0.1.0 // indirect
+)

go.sum

@@ -0,0 +1,10 @@
+github.com/eclipse/paho.mqtt.golang v1.4.3 h1:2kwcUGn8seMUfWndX0hGbvH8r7crgcJguQNCyp70xik=
+github.com/eclipse/paho.mqtt.golang v1.4.3/go.mod h1:CSYvoAlsMkhYOXh/oKyxa8EcBci6dVkLCbo5tTC1RIE=
+github.com/google/uuid v1.4.0 h1:MtMxsa51/r9yyhkyLsVeVt0B+BGQZzpQiTQ4eHZ8bc4=
+github.com/google/uuid v1.4.0/go.mod h1:TIyPZe4MgqvfeYDBFedMoGGpEw/LqOeaOT+nhxU+yHo=
+github.com/gorilla/websocket v1.5.0 h1:PPwGk2jz7EePpoHN/+ClbZu8SPxiqlu12wZP/3sWmnc=
+github.com/gorilla/websocket v1.5.0/go.mod h1:YR8l580nyteQvAITg2hZ9XVh4b55+EU/adAjf1fMHhE=
+golang.org/x/net v0.8.0 h1:Zrh2ngAOFYneWTAIAPethzeaQLuHwhuBkuV6ZiRnUaQ=
+golang.org/x/net v0.8.0/go.mod h1:QVkue5JL9kW//ek3r6jTKnTFis1tRmNAW2P1shuFdJc=
+golang.org/x/sync v0.1.0 h1:wsuoTGHzEhffawBOhz5CYhcrV4IdKZbEyZjBMuTp12o=
+golang.org/x/sync v0.1.0/go.mod h1:RxMgew5VJxzue5/jJTE5uejpjVlOe/izrB70Jof72aM=

main.go

@@ -0,0 +1,74 @@
+package main
+
+import "log"
+import "fmt"
+import "os"
+import "os/signal"
+import "strings"
+import MQTT "github.com/eclipse/paho.mqtt.golang"
+import "github.com/google/uuid"
+
+
+
+func onMessageReceived(client MQTT.Client, message MQTT.Message) {
+  log.Printf("Message received, topic: %s, payload: %s\n", message.Topic(), message.Payload())
+}
+
+func onConnectionLost(client MQTT.Client, error error) {
+  log.Printf("Connection lost, error %s", error)
+}
+
+func onReconnecting(client MQTT.Client, clientOpts *MQTT.ClientOptions) {
+  log.Println("Oops, connection lost, already reconnecting ...")
+}
+
+
+func onConnect(client MQTT.Client) {
+  topicsStr := os.Getenv("MQTT_SUBSCRIBE_TOPICS")
+  topics := strings.Split(topicsStr, ",")
+  for _, topic := range topics {
+    if token := client.Subscribe(topic, 0, onMessageReceived); token.Wait() && token.Error() != nil {
+      log.Fatalf("Unable to subscribe to topic %s, error %s", topic, token.Error())
+    }
+    log.Printf("Successfully subscribed to topic %s", topic)
+  }
+}
+
+
+func main() {
+  log.SetPrefix("UDI: ")
+  log.SetFlags(log.Ldate | log.Ltime | log.Lshortfile)
+
+  log.Println("UDI starting")
+
+  broker := os.Getenv("MQTT_BROKER")
+
+  prefix := "UDI"
+  uuid := uuid.New()
+  clientId := fmt.Sprintf("%s-%s", prefix, uuid)
+
+  mqttOpts := MQTT.NewClientOptions().
+    AddBroker(broker).
+    SetClientID(clientId).
+    SetConnectionLostHandler(onConnectionLost).
+    SetOnConnectHandler(onConnect).
+    SetReconnectingHandler(onReconnecting).
+    SetConnectRetry(true)
+
+  client := MQTT.NewClient(mqttOpts)
+  if token := client.Connect(); token.Wait() && token.Error() != nil {
+    log.Fatalf("Unable to connect to broker %s, error %s", broker, token.Error())
+  }
+  log.Printf("Successfully connected to broker %s", broker)
+
+
+  log.Println("UDI running")
+
+  c := make(chan os.Signal, 1)
+	signal.Notify(c, os.Interrupt, os.Kill)
+	<-c
+
+  log.Println("Terminating UDI")
+  client.Disconnect(250)
+}
+