Parameters description in the MqttPublisherSettings-0.json configuration file

Configuring the gateway > Configuring a connection over the MQTT protocol > Parameters description in the MqttPublisherSettings-0.json configuration file

Parameters description in the MqttPublisherSettings-0.json configuration file

The required parameters should be explicitly defined. The other parameters are optional. For optional parameters that are not included in the configuration file, the default value prescribed by the

MQTT protocol

may be used.

Parameters in the MqttPublisherSettings-0.json file

Parameter name	Required parameter	Description	Possible values and notes
`id`	Yes	ID of the MQTT client that will send data to the MQTT broker A server that receives, filters, and forwards messages over the MQTT protocol. .	`0`. The value of this parameter must match the value of the `sendingHubId` parameter in the `GuideSettings-0.json` configuration file.
`name`	Yes	Name of the MQTT client that will send data to the MQTT broker.	`<MQTT Publisher name>`. Example: `Kaspersky IoT Secure Gateway 100 MQTT Publisher`.
`description`	No	Description of the MQTT client that will send data to the MQTT broker.	`<MQTT Publisher description>`. Example: `Transfer data to MQTT Broker by Kaspersky IoT Secure Gateway 100`.
`clientId`	No	Unique identifier of the MQTT client.	`1`. The internal architecture of Kaspersky IoT Secure Gateway 100 involves interaction between a receiving hub and a sending hub. The `id` parameter is linked to the sending hub. The `clientId` parameter is linked to the MQTT protocol requirements and determines the ID of the MQTT client within this protocol. The `clientId` value must be unique among all clients connected to the MQTT broker.
`serverUri`	Yes	Address of the server that the MQTT client will connect to.	`<scheme>://<host>:<port>`. Example: `ssl://192.168.188.8:8883`. `ssl` is an architecture-prescribed scheme for querying a resource. `8883` is the default port.
`security`	Yes	Parameter block for configuring a secure connection. Contains the `clientPkiData` and `trustStore` parameter blocks.	`{clientPkiData, trustStore}` parameter block. The `security` parameter block is used to configure the certificates Data structure with a digital signature containing a public encryption key and the ID of the client or server. and encryption keys Component of a pair of encryption keys used for asymmetric encryption. Keys can be public or private. for the digital signature A value calculated with an encryption algorithm and added to data in such a way that any data recipient can use the signature to verify the origin and integrity of the data. and data encryption Conversion of data from readable format to encoded format. Encrypted data can be read or processed only after decryption. .
`clientPkiData`	Yes	Parameter block containing the names of the certificate and private encryption key files of the MQTT client for an encrypted connection.	`{certificate, privateKey}` parameter block.
`certificate`	Yes	Name of the file containing the certificate chain to the MQTT client certificate.	`mqtt-publisher.crt`.
`privateKey`	Yes	Private encryption key file name.	`mqtt-publisher.key`. The key length must be at least 2048 bits.
`trustStore`	Yes	Array that includes the name of the file containing the certificate chain to the MQTT broker certificate.	`ca-bundle.crt`. Name of the file containing the certificate chain to the certificate of the Certification Authority that signed the MQTT broker certificate.
`userCredentials`	Yes	Parameter block responsible for authentication of the MQTT client on the server.	`{username, password}` parameter block containing the user account credentials. `null` is indicated if you want to allow an anonymous connection of the MQTT client to the MQTT broker. In this case, you do not need to fill in the `username` and `password` fields.
`username`	No	Name of the user account for authorization on the MQTT server.	`<username>`.
`password`	No	Password of the user account for authorization on the MQTT server.	`<password>`.
`lastWill`	No	Parameter block for configuring a message informing that the client was improperly disconnected (LWT message).	`{topicName, message}` parameter block. The client can specify the LWT message when connecting to the MQTT broker for the first time. The MQTT broker will store this message until it detects an improper disconnection of the client. Upon detection of an improper connection, it will send the LWT message to all clients that have subscribed to this type of message. The MQTT broker does not send this message when the client is properly disconnected.
`topicName`	No	Name of the MQTT topic A hierarchical path to the data source used for sending messages over the MQTT protocol. that determines the information channel where the LWT message will be published.	`<topicName>`. Example: `LastWill`.
`message`	No	Contents of the LWT message.	`<message>`. Example: `LastMessage`.
`keepAlive`	No	Period of time that the MQTT broker can wait to receive a message from the MQTT client before terminating the connection due to inactivity.	`800`. The default value is `120`. Available values: `0`–`65535`. If the `keepAlive` value is equal to zero, the server will not be obligated to disconnect a client based on inactivity of the client. If the server deems a client to be inactive or if the client is not responding to queries, the server can disconnect the client at any time, irrespective of the `keepAlive` value provided by the client.
`qualityOfService`	No	Parameter defining a guarantee to send messages.	`1`. Agreement between the message sender (publisher) and message recipient (subscriber) that defines a guarantee to deliver a specific message. The MQTT specification defines the following three levels of `qualityOfService`: `0` is no more than one time: the client publishes messages without verifying whether they are delivered to the broker. Messages may be lost or duplicated. `1` is at least one time: the broker confirms delivery. Messages may be duplicated, but delivery is guaranteed. `2` is exactly one time: message delivery is guaranteed, and any potential duplication is eliminated. The default value is `1`.
`topics`	Yes	Array from the parameter blocks of MQTT topics.	Array of `[{id, name, topicName}]` parameter blocks. A separate parameter block in the array is completed for each MQTT topic.
`id`	Yes	ID of the destination port.	`<id>`. Example: `0`.
`name`	Yes	Name of the destination port. This name must match the outbound port `name` of one of the OPC UA Specification defining the protocols and mechanism for data transfer in industrial networks as well as interaction between devices in these networks. server data nodes indicated in the `nodes` parameter block in the `OpcUaClientSettings-0.json` configuration file.	`<name>`. Example: `Temperature`. To correctly transfer data from the OPC UA server to the MQTT broker, you need to map the MQTT topics to their corresponding OPC UA data nodes Structural element of an OPC UA information model containing data and metadata. . The `name` value is used for mapping.
`topicName`	Yes	Name of the MQTT topic.	`<topicName>`. Example: `Heartbeat`. See also: Special considerations when generating names of MQTT topics.

Article ID: 240940, Last review: May 24, 2023

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