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gopaho

publish to multiple brokers

I want to implement some sort of message fanout using https://github.com/eclipse/paho.mqtt.golang.

I was expecting the client to connect and publish to all the brokers. But I can see in their respective dashboards that it just connects to 1 of those brokers.

tgOpts := mqtt.NewClientOptions()
for _, target := range targets {
    tgOpts.AddBroker(target)
}

Do I have to create one client per target broker, or am I doing something wrong?

Solution

  • MQTT is a topic-based model, 1 broker has multiple clients, not the other way around.

    Some brokers (e.g. mosquitto) support bridging, which allows to build a fanout setup across brokers, but this setup is at broker level, the core MQTT functionality is still 1 broker per client connection. If you want to publish to multiple brokers, you'd need to connect to each one and publish individually.