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Configuration › Built-in Modules › stream_mqtt_preread module

stream_mqtt_preread module

stream_mqtt_preread module#

Enables extracting client IDs and usernames from CONNECT packets for Message Queuing Telemetry Transport (MQTT) versions 3.1.1 and 5.0.

When building from the source code, this module isn’t built by default; it should be enabled with the ‑‑with‑stream_mqtt_preread_module build option.

In packages and images from our repos, the module is included in the build.

Example Configuration#

Choosing an upstream server by the client ID:#

stream {

    mqtt_preread on;

    upstream mqtt {
        hash $mqtt_preread_clientid;
        # ...
    }
}

Directives#

mqtt_preread#

Syntax:

mqtt_preread on | off;

Default:

mqtt_preread off;

Context:

stream, server

Controls extracting information from CONNECT packets during the preread phase. If the setting is on, its surrounding context will have the following variables populated.

Built-in Variables#

See the details of the value semantics in the specification of MQTT versions 3.1.1 and 5.0.

$mqtt_preread_clientid#

Unique client ID.

$mqtt_preread_username#

Optional username.

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