Bridge

EMQ Node Bridge

Two or more EMQ brokers could be bridged together. Bridges forward MQTT messages from one broker node to another:

              ---------                     ---------                     ---------
Publisher --> | Node1 | --Bridge Forward--> | Node2 | --Bridge Forward--> | Node3 | --> Subscriber
              ---------                     ---------                     ---------

Configure Bridge

Suppose that we create two EMQ brokers on localhost:

Name	Node	MQTT Port
emqttd1	emqttd1@127.0.0.1	1883
emqttd2	emqttd2@127.0.0.1	2883

Create a bridge that forwards all the ‘sensor/#’ messages from emqttd1 to emqttd2.

1. Start Brokers

cd emqttd1/ && ./bin/emqttd start
cd emqttd2/ && ./bin/emqttd start

2. Create bridge: emqttd1–sensor/#–>emqttd2

$ cd emqttd1 && ./bin/emqttd_ctl bridges start emqttd2@127.0.0.1 sensor/#

bridge is started.

$ ./bin/emqttd_ctl bridges list

bridge: emqttd1@127.0.0.1--sensor/#-->emqttd2@127.0.0.1

3. Test the bridge

#emqttd2
mosquitto_sub -t sensor/# -p 2883 -d

#emqttd1
mosquitto_pub -t sensor/1/temperature -m "37.5" -d

4. Delete the bridge

./bin/emqttd_ctl bridges stop emqttd2@127.0.0.1 sensor/#

EMQ Bridge CLI

#query bridges
./bin/emqttd_ctl bridges list

#start bridge
./bin/emqttd_ctl bridges start <Node> <Topic>

#start bridge with options
./bin/emqttd_ctl bridges start <Node> <Topic> <Options>

#stop bridge
./bin/emqttd_ctl bridges stop <Node> <Topic>

mosquitto Bridge

Bridge mosquitto to emqttd broker:

             -------------             -----------------
Sensor ----> | mosquitto | --Bridge--> |               |
             -------------             |      EMQ      |
             -------------             |    Cluster    |
Sensor ----> | mosquitto | --Bridge--> |               |
             -------------             -----------------

mosquitto.conf

Suppose that we start an emqttd broker on localost:2883, and mosquitto on localhost:1883.

A bridge configured in mosquitto.conf:

connection emqttd
address 127.0.0.1:2883
topic sensor/# out 2

# Set the version of the MQTT protocol to use with for this bridge. Can be one
# of mqttv31 or mqttv311. Defaults to mqttv31.
bridge_protocol_version mqttv311

rsmb Bridge

Bridge RSMB to EMQ broker, same settings as mosquitto.

broker.cfg:

connection emqttd
addresses 127.0.0.1:2883
topic sensor/#