asyncapi.mqtt.proxy

asyncapi.mqtt.proxy

Listens on mqtt port 7183 and will forward mqtt publish messages and proxies subscribes to mosquitto MQTT broker listening on 1883 for topic smartylighting/streetlights/1/0/event/+/lighting/measured.

Requirements

• docker compose
• mosquitto

Setup

To start the Docker Compose stack defined in the compose.yaml file, use:

docker compose up -d

Verify behavior

Connect a subscribing client to mosquitto broker to port 1883. Using mosquitto_pub client publish {"id":"1","status":"on"} to Zilla on port 7183. Verify that the message arrived to on the first client.

docker compose -p zilla-asyncapi-mqtt-proxy exec -T mosquitto-cli \
    mosquitto_sub --url mqtt://zilla.examples.dev:7183/smartylighting/streetlights/1/0/event/+/lighting/measured --debug

output:

Client null sending CONNECT
Client auto-5A1C0A41-0D16-497D-6C3B-527A93E421E6 received CONNACK (0)
Client auto-5A1C0A41-0D16-497D-6C3B-527A93E421E6 sending SUBSCRIBE (Mid: 1, Topic: smartylighting/streetlights/1/0/event/+/lighting/measured, QoS: 0, Options: 0x00)
Client auto-5A1C0A41-0D16-497D-6C3B-527A93E421E6 received SUBACK
Subscribed (mid: 1): 0
{"id":"1","status":"on"}

docker compose -p zilla-asyncapi-mqtt-proxy exec -T mosquitto-cli \
    mosquitto_pub --url mqtt://zilla.examples.dev:7183/smartylighting/streetlights/1/0/event/1/lighting/measured --message '{"id":"1","status":"on"}' --debug

output:

Client null sending CONNECT
Client 244684c7-fbaf-4e08-b382-a1a2329cf9ec received CONNACK (0)
Client 244684c7-fbaf-4e08-b382-a1a2329cf9ec sending PUBLISH (d0, q0, r0, m1, 'smartylighting/streetlights/1/0/event/1/lighting/measured', ... (24 bytes))
Client 244684c7-fbaf-4e08-b382-a1a2329cf9ec sending DISCONNECT

Now attempt to publish an invalid message, with property stat instead of status.

docker compose -p zilla-asyncapi-mqtt-proxy exec -T mosquitto-cli \
    mosquitto_pub --url mqtt://zilla.examples.dev:7183/smartylighting/streetlights/1/0/event/1/lighting/measured --message '{"id":"1","stat":"off"}' --repeat 2 --repeat-delay 3 --debug

output:

Client null sending CONNECT
Client e7e9ddb0-f8c9-43a0-840f-dab9981a9de3 received CONNACK (0)
Client e7e9ddb0-f8c9-43a0-840f-dab9981a9de3 sending PUBLISH (d0, q0, r0, m1, 'smartylighting/streetlights/1/0/event/1/lighting/measured', ... (23 bytes))
Received DISCONNECT (153)
Error: The client is not currently connected.

Note that the invalid message is rejected with error code 153 payload format invalid, and therefore not received by the subscriber.

Teardown

To remove any resources created by the Docker Compose stack, use:

docker compose down