Files
universal-data-ingest/main.go

142 lines
3.3 KiB
Go

package main
import "log"
import "fmt"
import "os"
import "os/signal"
import "strings"
// import "time"
import MQTT "github.com/eclipse/paho.mqtt.golang"
import "github.com/google/uuid"
import "crypto/tls"
type Message struct {
topic string
payload []byte
}
var messageChannel chan Message
func onMessageReceived(client MQTT.Client, message MQTT.Message) {
// log.Printf("Message received, topic: %s, payload: %s\n", message.Topic(), message.Payload())
m := Message {
topic: message.Topic(),
payload: message.Payload(),
}
select {
case messageChannel <- m:
{}
//log.Println("Message sent to channel")
default:
log.Println("Channel full, message lost")
}
}
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")
if topicsStr == "" {
log.Fatal("No topics given, set env var 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 dispatcher() {
for {
select {
case message := <- messageChannel:
log.Printf("Message arrived in dispatcher, topic: %s, payload: %s\n", message.topic, message.payload)
}
}
}
func startMqttClient() MQTT.Client {
broker := os.Getenv("MQTT_BROKER")
if broker == "" {
log.Fatal("No broker given, set env var MQTT_BROKER")
}
prefix := "UDI"
uuid := uuid.New()
clientId := fmt.Sprintf("%s-%s", prefix, uuid)
opts := MQTT.NewClientOptions().
AddBroker(broker).
SetClientID(clientId).
SetConnectionLostHandler(onConnectionLost).
SetOnConnectHandler(onConnect).
SetReconnectingHandler(onReconnecting).
SetConnectRetry(true)
username := os.Getenv("MQTT_USERNAME")
if username != "" {
opts.SetUsername(username)
}
password := os.Getenv("MQTT_PASSWORD")
if password != "" {
opts.SetPassword(password)
}
enableTls := os.Getenv("MQTT_ENABLE_TLS")
if enableTls == "true" {
log.Println("Enableing TLS connection")
tlsConfig := &tls.Config {
InsecureSkipVerify: true,
}
opts.SetTLSConfig(tlsConfig)
}
log.Println("Trying to connect to broker")
client := MQTT.NewClient(opts)
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)
return client
}
func stopMqttClient(client MQTT.Client) {
log.Println("Disconnecting from broker")
client.Disconnect(250)
}
func main() {
log.SetPrefix("UDI: ")
log.SetFlags(log.Ldate | log.Ltime | log.Lshortfile)
log.Println("UDI starting")
messageChannel = make(chan Message, 100)
go dispatcher()
mqttClient := startMqttClient()
defer stopMqttClient(mqttClient)
log.Println("UDI running")
c := make(chan os.Signal, 1)
signal.Notify(c, os.Interrupt, os.Kill)
<-c
log.Println("Terminating UDI")
}