How to start MQTT publisher#

Pre-requisites:

Configure and start MQTT broker

Start the MQTT broker eclipse mosquitto using configuration configs/mosquitto.conf as below.

docker run -d --name=mqtt_broker -p 1883:1883 -v $PWD/configs/mosquitto.conf:/mosquitto/config/mosquitto.conf eclipse-mosquitto

With the above configuration, the broker listens on port 1883.

MQTT_HOST and MQTT_PORT environment variable must be set for DL Streamer Pipeline Server prior to sending this curl request. You can add them to the environments for DL Streamer Pipeline Server section in docker-compose.yml.
```
dlstreamer-pipeline-server:
  environment:
    MQTT_HOST: <HOST_IP>
    MQTT_PORT: 1883
```

The below CURL command publishes metadata to a MQTT broker and sends frames over WebRTC for streaming.

Assuming broker is running in the same host over port 1883, replace the <HOST_IP> field with your system IP address.
WebRTC Stream will be accessible at http://<HOST_IP>:8889/mqttstream.

curl http://<HOST_IP>:8080/pipelines/user_defined_pipelines/weld_porosity_classification_mqtt -X POST -H 'Content-Type: application/json' -d '{
    "source": {
        "uri": "file:///home/pipeline-server/resources/videos/welding.avi",
        "type": "uri"
    },
    "destination": {
        "metadata": {
            "type": "mqtt",
            "publish_frame":true,
            "topic": "weld_porosity_classification"
        },
        "frame": {
            "type": "webrtc",
            "peer-id": "mqttstream",
            "overlay": false
        }
    },
    "parameters": {
        "classification-properties": {
            "model": "/home/pipeline-server/resources/models/weld_porosity/weld_porosity_classification/deployment/Classification/model/model.xml",
            "device": "CPU"
        }
    }
}'

In the above curl command set publish_frame to false if you don’t want frames sent over MQTT. Metadata will be sent over MQTT.

Output can be viewed on MQTT subscriber as shown below.

docker run -it --entrypoint mosquitto_sub eclipse-mosquitto:latest --topic weld_porosity_classification -p 1883 -h <HOST_IP>