HiveMQ Enterprise Extension for Microsoft SQL Server

Microsoft SQL Server (MSSQL) is a relational database management system from Microsoft that is used across on-premise and cloud environments to store, manage, and analyze data.

Features

Forward MQTT messages from IoT devices that are connected to your HiveMQ MQTT broker to one or more Microsoft SQL Server/Azure SQL databases.
Convert MQTT messages into Microsoft SQL Server rows with convenient insert statements.

Requirements

A running HiveMQ Professional or Enterprise Edition installation, version 4.33 or higher.
A running Microsoft SQL Server database system. Version 2019 or higher is recommended.
For production use, a valid HiveMQ Enterprise Extension for Microsoft SQL Server license.

If you do not provide a valid license, HiveMQ automatically uses a free trial license. Trial licenses for HiveMQ Enterprise Extensions are valid for 5 hours. For more license information or to request an extended evaluation license, contact HiveMQ sales.

Installation

Place your HiveMQ Enterprise Extension for Microsoft SQL Server license file (.elic) in the license folder of your HiveMQ installation. (Skip this step if you are using a trial version of the extension).

└─ <HiveMQ folder>
    ├─ bin
    ├─ conf
    ├─ data
    ├─ extensions
    │   ├─ hivemq-microsoft-sql-server-extension
    │   └─ ...
    ├─ license
    ├─ log
    └─ ...

Before you enable the extension, you need to configure the extension to match your individual Microsoft SQL Server setup.
For your convenience, we provide an example configuration conf/examples/config.xml that you can copy and modify as desired.
The included config.xsd file outlines the schema and elements that can be used in the XML configuration.
Your completed configuration file must be named config.xml and located in HIVEMQ_HOME/extensions/hivemq-microsoft-sql-server-extension/conf/config.xml.
For detailed information on configuration options, see Configuration.
To enable the HiveMQ Enterprise Extension for Microsoft SQL Server, locate the hivemq-microsoft-sql-server-extension folder in the extensions directory of your HiveMQ installation and remove the DISABLED file (if present).

To function properly, the HiveMQ Enterprise Extension for Microsoft SQL Server must be installed on all HiveMQ broker nodes in your HiveMQ cluster and the configuration file on each node must be identical.

Configuration

The extension configuration is divided into two sections:

MSSQLs: Provides information about the MSSQL databases to which your HiveMQ broker connects.
MQTT to MSSQL Routes: Defines how MQTT messages are sent from your HiveMQ broker to the configured MSSQL databases.

Extension Configuration File

The config.xml file for your Microsoft SQL Server extension must be located in the hivemq-microsoft-sql-server-extension/conf/ folder within the extensions folder of your HiveMQ installation.

The extension uses a simple but powerful XML-based configuration.

The conf/examples/config.xml file is a configuration example that has all the parameters you need to send MQTT messages from your HiveMQ MQTT broker to Microsoft SQL Server.

If you copy and reuse the conf/examples/config.xml file, be sure to move the file to /conf/config.xml before you enable your extension. For more information, see Installation.

Example extension configuration

<hivemq-microsoft-sql-server-extension xmlns:xsi="http://www.w3.org/2001/XMLSchema-instance"
                             xsi:noNamespaceSchemaLocation="config.xsd">
    <mssqls>
        <mssql>
            <id>my-mssql-id</id>
            <server-name>my.host.com</server-name>
            <port>1433</port>
            <database>my-database</database>
            <authentication>
                <basic>
                    <username>my-user</username>
                    <password>my-password</password>
                </basic>
            </authentication>
        </mssql>
    </mssqls>

    <mqtt-to-mssql-routes>
        <mqtt-to-mssql-route>
            <id>my-mqtt-to-mssql-route-insert</id>
            <mssql-id>my-mssql-id</mssql-id>
            <mqtt-topic-filters>
                <mqtt-topic-filter>#</mqtt-topic-filter>
            </mqtt-topic-filters>
            <processor>
                <insert-statement>
                    <table>mqtt_to_mssql_table</table>
                    <use-bulk-copy>true</use-bulk-copy>
                    <columns>
                        <column>
                            <name>topic</name>
                            <value>mqtt-topic</value>
                        </column>
                        <column>
                            <name>payload_utf8</name>
                            <value>mqtt-payload-utf8</value>
                        </column>
                    </columns>
                </insert-statement>
            </processor>
        </mqtt-to-mssql-route>
    </mqtt-to-mssql-routes>
</hivemq-microsoft-sql-server-extension>

MSSQL Databases Configuration

The <mssqls> section of your configuration lists the MSSQL databases to which configured MQTT messages are routed.

You can define as many <mssql> tags as your use case requires.

Example MSSQL database connection configuration

<mssqls>
    <mssql>
        <id>my-mssql-id</id>
        <server-name>my.host.com</server-name>
        <port>1433</port>
        <database>my-database</database>
        <authentication>
            <basic>
                <username>my-user</username>
                <password>my-password</password>
            </basic>
        </authentication>
    </mssql>
</mssqls>

Example MSSQL database connection with a TLS configuration

<mssqls>
    <mssql>
        <id>my-mssql-id</id>
        <server-name>my.host.com</server-name>
        <port>1433</port>
        <database>my-database</database>
        <authentication>
            <basic>
                <username>my-user</username>
                <password>my-password</password>
            </basic>
        </authentication>
        <tls>
            <trust-server-certificate>false</trust-server-certificate>
            <truststore>
                <path>/truststore.jks</path>
                <password>changeme</password>
            </truststore>
        </tls>
    </mssql>
</mssqls>

You can use Environment variables to map properties such as the MSSQL password.

Table 1. MSSQL configuration parameters
Parameter	Required	Type	Description
`id`		ID	The ID of the MSSQL connection. This string can only contain lowercase alphanumeric characters, dashes, and underscores.
`server-name`		String	The server name of the MSSQL database.
`port`		Integer	The port of the MSSQL database.
`database`		String	The name of the MSSQL database.
`authentication`		Complex	Defines the type of authentication the extension uses for the MSSQL connection. `basic`: Username and password based authentication. `username`: The username required to establish the connection to MSSQL. `password`: The password required to establish the connection to MSSQL.
`tls`	-	Complex	Optional TLS configuration to establish a secure connection to MSSQL. Currently, only TLS 1.2 is supported. `enabled`: Optional setting that defines whether the TLS configuration is used to encrypt communication between the extension and MSSQL. The default setting is `true`. To disable your TLS configuration, set the `enabled` parameter to `false`. `trust-server-certificate`: Optional setting that defines whether to use the server-name to validate the server certificate. The default setting is `false`. To disable certificate validation, set this to `true`. `host-name-in-certificate`: Optional setting that defines the host name to be used to validate the server certificate. Set this option when the name in the certificate does not match the server-name. `truststore`: Optional configuration of a truststore that contains the list of trusted certificates. `path`: The path to the PKCS#12 (.p12/.pfx) or JKS (.jks) truststore where trusted certificates are stored. `password`: The password for the truststore.

MQTT to MSSQL Routes

The <mqtt-to-mssql-routes> section of your extension configuration defines how MQTT messages are sent from the HiveMQ broker to Microsoft SQL Server.

You can define as many <mqtt-to-mssql-route> tags as your use case requires.

Example MQTT to MSSQL route with an insert statement configuration

<mqtt-to-mssql-route>
    <id>my-mqtt-to-mssql-route-insert</id>
    <mssql-id>my-mssql-id</mssql-id>
    <mqtt-topic-filters>
        <mqtt-topic-filter>#</mqtt-topic-filter>
    </mqtt-topic-filters>
    <processor>
        <insert-statement>
            <table>mqtt_to_mssql_table</table>
            <use-bulk-copy>true</use-bulk-copy>
            <columns>
                <column>
                    <name>topic</name>
                    <value>mqtt-topic</value>
                </column>
                <column>
                    <name>payload_utf8</name>
                    <value>mqtt-payload-utf8</value>
                </column>
            </columns>
        </insert-statement>
    </processor>
</mqtt-to-mssql-route>

Table 2. MSSQL route parameters
Parameter	Required	Type	Description
`id`		ID	The ID of the `mqtt-to-mssql-route`. This string can only contain lowercase alphanumeric characters, dashes, and underscores.
`mssql-id`		IDREF	The ID of the MSSQL database.
`enabled`	-	Boolean	Optional setting that defines whether the selected `mqtt-to-mssql-route` is enabled or disabled. The default setting is `true`. To disable the route, set to `false`.
`mqtt-topic-filters`		String	A list of one or more MQTT topic filters. `mqtt-topic-filter`: The source MQTT topic filters to select which MQTT messages are routed to the MSSQL database. You can define as many individual `<mqtt-topic-filter>` tags as your use case requires.
`processor`		Complex	Defines how HiveMQ converts MQTT messages into MSSQL rows. `insert-statement`: Use the XML configuration to define how to insert rows into MSSQL. `table`: The name of the table where rows are inserted. `use-bulk-copy`: Optional setting to enable or disable bulk copy for batch insert. The default setting is `true`. To disable bulk copy, set to `false`. `columns`: A list of the table columns where values are inserted. `column`: A column name and value binding. `name`: The name of the column where the value is inserted. `value`: The MQTT property placeholder to replace and bind to the selected column.

Bulk copy does not support all data types and has additional known limitations. Although most of the limitations do not apply to the extension, verify that you are not using any data types listed as not supported. If an unsupported data type is detected, bulk copy is automatically disabled, resulting in lower performance.

Insert Statements

Insert statements help you convert MQTT messages into MSSQL rows.

The insert statements provide the table name, target columns, and respective value placeholders. The extension fills the placeholders with MQTT PUBLISH properties and appends those to the batch of values to insert. Batching for insert statements is always enabled to optimize performance and throughput.

Example insert statement

<insert-statement>
    <table>mqtt_to_mssql_table</table>
    <use-bulk-copy>true</use-bulk-copy>
    <columns>
        <column>
            <name>topic</name>
            <value>mqtt-topic</value>
        </column>
        <column>
            <name>payload_utf8</name>
            <value>mqtt-payload-utf8</value>
        </column>
    </columns>
</insert-statement>

The following table lists all placeholders the HiveMQ MSSQL extension recognizes:

Table 3. Available placeholders
Name	MSSQL recommend data type	Description
`mqtt-topic`	NVARCHAR	The topic of the MQTT PUBLISH.
`mqtt-payload-utf8`	NVARCHAR	The payload of the MQTT PUBLISH as a UTF-8 string.
`mqtt-payload-base64`	NVARCHAR	The payload of the MQTT PUBLISH as a Base64 string.
`mqtt-qos`	NVARCHAR	The QoS level of the MQTT PUBLISH (AT_MOST_ONCE, AT_LEAST_ONCE, EXACTLY_ONCE).
`mqtt-retain`	BIT	The retain flag of the MQTT PUBLISH.
`mqtt-packet-id`	INT	The packet ID of the MQTT PUBLISH.
`mqtt-payload-format-indicator`	NVARCHAR	The payload format indicator of the MQTT PUBLISH.
`mqtt-response-topic`	NVARCHAR	The response topic of the MQTT PUBLISH.
`mqtt-correlation-data-utf8`	NVARCHAR	The correlation data of the MQTT PUBLISH as a UTF-8 string.
`mqtt-correlation-data-base64`	NVARCHAR	The correlation data of the MQTT PUBLISH as a Base64 string.
`mqtt-user-properties-json`	NVARCHAR	The user properties of the MQTT PUBLISH as a JSON array string.
`mqtt-user-properties$property-name`	NVARCHAR	The value of the user property of the MQTT PUBLISH with the matching property name. Example: `mqtt-user-properties$myUserPropertyName` will bind the value of the first user property with the name `myUserPropertyName`.
`timestamp-ms`	BIGINT	The arrival timestamp of the PUBLISH message represented as a UNIX timestamp value in milliseconds. The timestamp of an incoming PUBLISH message records the moment the message arrived at the broker. The timestamp of a message created via the Extension SDK records the moment the message passed to the PublishService. The timestamp of a Will Publish message sent to subscribers records the moment the delivery of the message started.
`timestamp-iso-8601`	DATETIME2	The same information as `timestamp-ms` represented as an ISO 8601 string. Since bulk copy does not support DATETIMEOFFSET, we recommend using DATETIME2 instead. Normally, this format is not a problem for machines running in UTC. However, be sure to note the lack of timezone information.

Some properties in an MQTT PUBLISH message are optional. The number of placeholders the MSSQL extension fills varies based on the properties that are present in the MQTT PUBLISH message.

Environment variables

HiveMQ offers placeholders that can be replaced with the content of environment variables when the configuration file is read. For many use cases, it can be beneficial or necessary to use environment variables to configure items such as ports and bind addresses on the system on which you run HiveMQ. For example, when you run HiveMQ in a containerized environment.

You can use ${YOUR_ENVVAR_NAME} in the config.xml file. HiveMQ replaces the placeholder with the value of the specified environment variable during startup.

Example to set an environment variable

export MY_MSSQL_PASSWORD=my-password

Example use of the environment variable in the configuration

<mssql>
    <id>my-mssql-id</id>
    <server-name>my.host.com</server-name>
    <port>1433</port>
    <database>my-database</database>
    <authentication>
        <basic>
            <username>my-user</username>
            <password>${MY_MSSQL_PASSWORD}</password>
        </basic>
    </authentication>
</mssql>

Result of the example configuration in HiveMQ

<mssql>
    <id>my-mssql-id</id>
    <server-name>my.host.com</server-name>
    <port>1433</port>
    <database>my-database</database>
    <authentication>
        <basic>
            <username>my-user</username>
            <password>my-password</password>
        </basic>
    </authentication>
</mssql>

Make sure that HiveMQ is started in the same context as your environment variables are set, otherwise HiveMQ will not be able to access them.