MQTT

The MQTT node-type uses [libmosquitto] to publish and subscribe messages via the MQTT protocol. It is similiar to the Advanced Messaging & Queuing Protocol (AMQP) node-type.

Prerequisites

This node-type requires mosquitto (>= 1.4.15).

Implementation

The source code of the node-type is available here: https://git.rwth-aachen.de/acs/public/villas/node/blob/master/lib/nodes/mqtt.cpp

Configuration

format (string)

The payload format which is used to encode and decode exchanged messages.

username (string)

The username which is used for authentication with the MQTT broker.

password (string)

The password which is used for authentication with the MQTT broker.

host (string)

The hostname of the MQTT broker.

port (integer) = 1883

The port number of the MQTT broker.

retain (boolean) = false

keepalive (integer) = 1

qos (integer) = 0

Example

nodes = {
        mqtt_node = {
                type = "mqtt",
                
                format = "protobuf",
                
                username = "guest",
                password = "guest",
                host = "localhost",
                port = 1883,
                
                keepalive = 5,                          # Send ping every 5 seconds to keep connection alive
                retain = false,
                qos = 0,

                out = {
                        publish = "test-topic"
                },
                in = {
                        subscribe = "test-topic"
                },
                ssl = {
                        enabled = false,
                        insecure = true,
                        cafile = "/etc/ssl/certs/ca-bundle.crt",
                        certfile = "/etc/ssl/certs/my.crt",
                        keyfile = "/etc/ssl/keys/my.key"
                }
        }
}