gen_mqtt_service

Generate MQTT service

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MQTT broker

The MQTT broker is software running on a computer (running on-premises or in the cloud), and could be self-built or hosted by a third party. It is available in both open source and proprietary implementations.

The broker acts as a post office, MQTT doesn’t use the address of the intended recipient but uses the subject line called “Topic”, and anyone who wants a copy of that message will subscribe to that topic. Multiple clients can receive the message from a single broker (one to many capability). Similarly, multiple publishers can publish topics to a single subscriber (many to one).

Each client can both produce and receive data by both publishing and subscribing, i.e. the devices can publish sensor data and still be able to receive the configuration information or control commands (MQTT is a bi-directional communication protocol). This helps in both sharing data, managing and controlling devices.

With MQTT broker architecture, the devices and application becomes decoupled and more secure. MQTT uses Transport Layer Security (TLS) encryption with user name, password protected connections, and optional certifications that requires clients to provide a certificate file that matches with the server’s. The clients are unaware of each other’s IP address.

In case of a single source of failure, broker software and clients have an automatic handover to Redundant/automatic backup broker. The backup broker can also be set up to share the load of clients across multiple servers onsite, cloud, or the combination of both.

The broker can support both standard MQTT and MQTT for compliant specifications such as Sparkplug, can be done with same server, same time and with same levels of security.

The broker can store the data in the form of retained messages (need to subscribe with database client) so that new subscribers to the topic can get the last value straight away.

The broker also keeps track of all the session’s information as the devices goes on and off called “persistent sessions”.

Example of MQTT service for tracking temperature

Temperature tracking based on MQTT

Advantages

The main advantages of MQTT broker are:

eliminates vulnerable and insecure client connections
can easily scale from a single device to thousands
manages and tracks all client connection states, including security credentials and certificates
reduced network strain without compromising the security (cellular or satellite network)

Embedded Broker Support

If you need a lightweight, self-contained environment without deploying an external broker daemon, gen_mqtt_service provides the node_ws template with an embedded Aedes MQTT broker capable of serving both WebSockets (ws://localhost:8080) and TCP (mqtt://localhost:1883) simultaneously. For setup and execution details, see the Templates Architecture & Usage Guide.