MQTT demo with Go

Architecture

Configuration messages

graph TD
    MQTT[MQTT Broker]
    AdminClient[Admin Client]
    AdminManagerUI[Admin Manager UI]
    KioskClient[Kiosk Client]
    KioskUI[Kiosk UI]

    subgraph Admin Manager Interface
        AdminManagerUI -->|Sends config to| AdminClient
        AdminClient -->|Publishes config to|MQTT
    end

    subgraph Kiosk Web Interface
        MQTT -->|Forwards config to| KioskClient
        KioskUI -->|Requests config from| KioskClient
        KioskClient -->|Returns config to| KioskUI
    end

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Sensor messages

graph TD
    MQTT2[MQTT Broker]
    AdminClient2[Admin Client]
    AdminMonitorUI[Admin Monitor UI]
    KioskClient2[Kiosk Client]
    KioskUI2[Kiosk UI]

    subgraph Kiosk Web Interface
        KioskUI2 -->|Sends sensors to| KioskClient2
        KioskClient2 -->|Publishes sensors to|MQTT2
    end

    subgraph Admin Monitor Interface
        MQTT2 -->|Forwards sensors to| AdminClient2
        AdminMonitorUI -->|Requests sensors from| AdminClient2
        AdminClient2 -->|Returns sensors to| AdminMonitorUI
    end

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Environment variables

Key	Description
BROKER_ADDRESS	Broker or server address
BROKER_MQTT_PORT	Broker or server MQTT TLS/SSL port
BROKER_WS_PORT	Broker or server WebSocket TLS/SSL port
CLIENT_ID_SUFFIX	Unique client ID suffix
MQTT_USERNAME
MQTT_PASSWORD
MQTT_CLEAN_SESSION	Value is 0 or 1
MQTT_MAX_RECONNECT_INTERVAL	Default 10s
SERVICE_PORT	Port which the service will be bind to
LOCATION_ID	Location identifier
KIOSK_ID	Kiosk identifier
DEBUG	Log with debug mode. Value is 0 or 1

Commands

Admin

Example .env file:

BROKER_ADDRESS=broker.emqx.io
BROKER_PORT=8883
BROKER_WS_PORT=8084
CLIENT_ID_SUFFIX=admin1
MQTT_USERNAME=emqx
MQTT_PASSWORD=public
MQTT_CLEAN_SESSION=0
MQTT_MAX_RECONNECT_INTERVAL=10s
SERVICE_PORT=8080
LOCATION_ID=1
DEBUG=0

Run command:

cd admin
go run .

For succeeding instances (through separate terminals):

cd admin
SERVICE_PORT=7979 LOCATION_ID=2 CLIENT_ID_SUFFIX=admin2 go run .

Kiosk

Example .env file:

BROKER_ADDRESS=broker.emqx.io
BROKER_PORT=8883
BROKER_WS_PORT=8084
CLIENT_ID_SUFFIX=loc1_kiosk1
MQTT_USERNAME=emqx
MQTT_PASSWORD=public
MQTT_CLEAN_SESSION=0
MQTT_MAX_RECONNECT_INTERVAL=10s
SERVICE_PORT=8181
LOCATION_ID=1
KIOSK_ID=1
DEBUG=0

Run command:

cd kiosk
go run .

For succeeding instances (through separate terminals):

cd kiosk
SERVICE_PORT=8282 CLIENT_ID_SUFFIX=loc1_kiosk2 KIOSK_ID=2 go run .

cd kiosk
SERVICE_PORT=8383 CLIENT_ID_SUFFIX=loc2_kiosk1 LOCATION_ID=2 KIOSK_ID=1 go run .