MQTT action

The action is used for publish output message into an MQTT server.

Property name	Optional	Description
server	false	The broker address of the MQTT server, such as tcp://127.0.0.1:1883
topic	false	The MQTT topic, such as analysis/result
clientId	true	The client id for MQTT connection. If not specified, an uuid will be used
protocolVersion	true	MQTT protocol version. 3.1 (also refer as MQTT 3) or 3.1.1 (also refer as MQTT 4). If not specified, the default value is 3.1.
qos	true	The QoS for message delivery. Only int type value 0 or 1 or 2.
username	true	The username for the connection.
password	true	The password for the connection.
certificationPath	true	The certification path. It can be an absolute path, or a relative path. If it is an relative path, then the base path is where you excuting the kuiperd command. For example, if you run bin/kuiperd from /var/kuiper, then the base path is /var/kuiper; If you run ./kuiperd from /var/kuiper/bin, then the base path is /var/kuiper/bin.
privateKeyPath	true	The private key path. It can be either absolute path, or relative path, which is similar to use of certificationPath.
rootCaPath	true	The location of root ca path. It can be an absolute path, or a relative path, which is similar to use of certificationPath.
certficationRaw	true	base64 encoded original text of cert, use certificationPath first if both defined
privateKeyRaw	true	base64 encoded original text of key, use privateKeyPath if both defined
rootCARaw	true	base64 encoded original text of CA, use rootCaPath first if both defined
tlsMinVersion	true	Specifies the minimum version of the TLS protocol that will be negotiated with the client. Accept values are tls1.0, tls1.1, tls1.2 and tls1.3. Default: tls1.2.
renegotiationSupport	true	Determines how and when the client handles server-initiated renegotiation requests. Support never, once or freely options. Default: never.
insecureSkipVerify	true	If InsecureSkipVerify is true, TLS accepts any certificate presented by the server and any host name in that certificate. In this mode, TLS is susceptible to man-in-the-middle attacks. The default value is false. The configuration item can only be used with TLS connections.
retained	true	If retained is true,The broker stores the last retained message and the corresponding QoS for that topic.The default value is false.
compression	true	Compress the payload with the specified compression method. Support zlib, gzip, flate, zstd method now.
connectionSelector	true	reuse the connection to mqtt broker. more info

Other common sink properties are supported. Please refer to the sink common properties for more information.

Below is sample configuration for connecting to Azure IoT Hub by using SAS authentication.

    {
      "mqtt": {
        "server": "ssl://xyz.azure-devices.net:8883",
        "topic": "devices/demo_001/messages/events/",
        "protocolVersion": "3.1.1",
        "qos": 1,
        "clientId": "demo_001",
        "username": "xyz.azure-devices.net/demo_001/?api-version=2018-06-30",
        "password": "SharedAccessSignature sr=*******************",
        "retained": false
      }
    }

Below is another sample configuration for connecting to AWS IoT by using certification and privte key auth.

    {
      "mqtt": {
        "server": "ssl://xyz-ats.iot.us-east-1.amazonaws.com:8883",
        "topic": "devices/result",
        "qos": 1,
        "clientId": "demo_001",
        "certificationPath": "keys/d3807d9fa5-certificate.pem",
        "privateKeyPath": "keys/d3807d9fa5-private.pem.key",
        "insecureSkipVerify": false,
        "retained": false
      }
    }

You can check the connectivity of the corresponding sink endpoint in advance through the API: Connectivity Check

Dynamic Topic

If the result data contains the topic name, we can use it as the property of the mqtt action to achieve dynamic topic support. Assume the selected data has a field named mytopic, we can use data template syntax to set it as the property value for topic as below:

    {
      "mqtt": {
        "server": "ssl://xyz-ats.iot.us-east-1.amazonaws.com:8883",
        "topic": "{{.mytopic}}",
        "qos": 1,
        "clientId": "demo_001",
        "certificationPath": "keys/d3807d9fa5-certificate.pem",
        "privateKeyPath": "keys/d3807d9fa5-private.pem.key",
        "retained": false
      }
    }