MQTT is a publish/subscribe protocol that allows clients to listen to a stream of events produced to a server.
It is widely used in real-time and IoT applications since it is lightweight and easy to use.
type: mqtt-source
version: 0.5.3
The inbound MQTT connector supports the following configuration options:
required
The hostname of the MQTT server to subscribe to
This value can be provided as a parameter or as a secret
required
The topic filter to use when receiving MQTT events
version: 0.5.3
name: my-mqtt
type: mqtt-source
topic: mqtt-topic
parameters:
mqtt_topic: "/hfp/v2/journey/#"
secrets:
MQTT_URL: mqtts://mqtt.hsl.fi:8883/
There are two important pieces of information that we’re interested in capturing from every MQTT event.
- The topic the event was sent to
- The body of the event
In MQTT, topics are more of a label for particular message types. When we specify a
mqtt-topic to subscribe to, we are actually defining a “filter”, or a pattern that
tells MQTT which events we are interested in receiving.
This means that events we receive may not all belong to the same topic - rather, they all match the filter we provided.
The result of the event message body produced to Fluvio by the inbound MQTT connector is a JSON object containing:
- MQTT topic name
- MQTT message body
Furthermore, since MQTT allows events to contain arbitrary binary data, the payload is encoded as a byte buffer.
Below is a sample of what an MQTT event captured and sent to Fluvio looks like:
{"mqtt_topic":"/hfp/v2/journey/ongoing/vp/bus/0022/01151/2200/1/Espoon keskus/23:02/1160105/4/60;24/29/00/00","payload":[123,34,86,80,34,58,123,34,100,101,115,105,34,58,34,50,48,48,34,44,34,100,105,114,34,58,34,49,34,44,34,111,112,101,114,34,58,50,50,44,34,118,101,104,34,58,49,49,53,49,44,34,116,115,116,34,58,34,50,48,50,49,45,49,49,45,49,56,84,50,49,58,49,51,58,51,50,46,56,56,52,90,34,44,34,116,115,105,34,58,49,54,51,55,50,55,48,48,49,50,44,34,115,112,100,34,58,49,50,46,54,55,44,34,104,100,103,34,58,51,51,55,44,34,108,97,116,34,58,54,48,46,50,48,48,49,53,55,44,34,108,111,110,103,34,58,50,52,46,57,48,48,50,49,53,44,34,97,99,99,34,58,45,48,46,49,49,44,34,100,108,34,58,45,55,53,44,34,111,100,111,34,58,110,117,108,108,44,34,100,114,115,116,34,58,110,117,108,108,44,34,111,100,97,121,34,58,34,50,48,50,49,45,49,49,45,49,56,34,44,34,106,114,110,34,58,49,53,48,44,34,108,105,110,101,34,58,49,48,52,52,44,34,115,116,97,114,116,34,58,34,50,51,58,48,50,34,44,34,108,111,99,34,58,34,71,80,83,34,44,34,115,116,111,112,34,58,110,117,108,108,44,34,114,111,117,116,101,34,58,34,50,50,48,48,34,44,34,111,99,99,117,34,58,48,125,125]}
