spin-trigger-mqtt VS mqtt.org

The MQTT trigger is a feature of the Spin framework that allows a Spin application to subscribe to a specific MQTT address. Individual components within that application can then be configured to monitor particular topics at the address. When messages are detected on these topics, the corresponding component functions are triggered.

Let’s start by looking at the implementation of our first component, which is triggered by messages published to an MQTT topic and persists the data in a SQLite database. It is implemented in Rust and was scaffolded using the MQTT template. In the Spin application manifest (spin.toml), we are using a Spin application variable to dynamically configure the address for the MQTT broker. This will enable us to set Spin to connect to a broker at "mqtt://localhost:1883" when running locally and at "mqtt://emqx.default.svc.cluster.local:1883" when running in SpinKube. We also set the keep alive interval (secs) for connections with the broker and username and password authentication credentials. In this example application, the broker does not require authentication, so the credentials are left empty.

We will explore a Spin application that uses the MQTT trigger and deploy it to run on your Kubernetes cluster using SpinKube, whether on the edge or in the cloud. MQTT is a lightweight, publish-subscribe messaging protocol that enables devices to send and receive messages through a broker. Our Spin app will receive MQTT messages from sound devices that are at each booth and chart booth volume over time. The result is a visual graph of engagement at each booth.

RabbitMQ is an open-source message broker software that implements a handful of messaging protocols, originally the AMQP (Advanced Message Queuing Protocol), and also includes web-based ones such as STOMP (Simple Text Orientated Messaging Protocol), MQTT (Message Queuing Telemetry Transport), and WebSockets to decouple applications that share asynchronous data. RabbitMQ not only serves as an attractive messaging system choice due to its robustness and well-maintained open-source nature but also stands out for its ease of use and configuration. Before creating our first RabbitMQ instance and cluster, let's explore some fundamental concepts around messaging and check out some common use cases.

Mosquitto itself does not support cluster deployment, but it can be implemented through the backend, see MQTT server support for details.

'$' is a reserved prefix for internal topics, even if you subscribe with a single '#', the Broker will not send them to you unless you explicitly subscribe, like the common $SYS topics;

MQTT (optional): If you're aiming for advanced customization, familiarity with MQTT (a lightweight messaging protocol) will be beneficial for communicating between the toy and the server.

The MQTT protocol is widely used in IoT applications because of its simplicity and ability to connect different data sources to applications using a publish/subscribe model. While many MQTT brokers support persistent sessions and can store message history as long as an MQTT client is not available, there may be cases where data needs to be stored for a longer period. In such cases, it is recommended to use a time series database. There are many options available, but if you need to store unstructured data such as images, sensor data, or Protobuf messages, consider using ReductStore. It is a time series database specifically designed for storing large amounts of blob data and optimized for IoT and edge computing.

https://mqtt.org is more popular, but its more complex. You will unlikely write your own mqtt while you can easily write own stomp broker.

I wanted to share my latest package (published on NuGet) implementing the MQTT v5 protocol.

I jumped onto https://mqtt.org/ to try to answer my usual use-case question about non-Kafka messaging, which is: "Do the messages get saved anywhere so you can come back and read them later?" Still not entirely sure about it.

But I did see:

    This is why MQTT has 3 defined quality of service levels: 0 - at most once, 1- at least once, 2 - exactly once