MQTT Bridge

The technical documentation of the mqtt-bridge microservice, which acts as a communication bridge between two MQTT brokers.

2 minute read

MQTT-bridge is a microservice that connects two MQTT brokers and forwards messages between them. It is used to connect the local broker of the edge computer with the remote broker on the server.

How it works

This microservice subscribes to topics on the local broker and publishes the messages to the remote broker, while also subscribing to topics on the remote broker and publishing the messages to the local broker.

Kubernetes resources

StatefulSet: united-manufacturing-hub-mqttbridge
Secret: united-manufacturing-hub-mqttbridge-mqtt-secrets
PersistentVolumeClaim: united-manufacturing-hub-mqttbridge-claim

Configuration

You can configure the URL of the remote MQTT broker that MQTT-bridge should connect to by setting the value of the remoteBrokerUrl parameter in the _000_commonConfig.mqttBridge section of the Helm chart values file.

Environment variables

Environment variables
Variable name	Description	Type	Allowed values	Default
`BRIDGE_ONE_WAY`	Whether to enable one-way communication, from local to remote	`bool`	`true`, `false`	`true`
`INSECURE_SKIP_VERIFY_LOCAL`	Skip TLS certificate verification for the local broker	`bool`	`true`, `false`	`true`
`INSECURE_SKIP_VERIFY_REMOTE`	Skip TLS certificate verification for the remote broker	`bool`	`true`, `false`	`true`
`LOCAL_BROKER_SSL_ENABLED`	Whether to enable SSL for the local MQTT broker	`bool`	`true`, `false`	`true`
`LOCAL_BROKER_URL`	URL for the local MQTT broker	string	Any	ssl://united-manufacturing-hub-mqtt:8883
`LOCAL_CERTIFICATE_NAME`	Set to NO_CERT to allow non-encrypted MQTT access, or to USE_TLS to use TLS encryption	string	USE_TLS, NO_CERT	USE_TLS
`LOCAL_PUB_TOPIC`	Local MQTT topic to publish to	string	Any	ia
`LOCAL_SUB_TOPIC`	Local MQTT topic to subscribe to	string	Any	ia/factoryinsight
`MQTT_PASSWORD`	Password for the MQTT broker	string	Any	INSECURE_INSECURE_INSECURE
`REMOTE_BROKER_SSL_ENABLED`	Whether to enable SSL for the remote MQTT broker	`bool`	`true`, `false`	`true`
`REMOTE_BROKER_URL`	URL for the local MQTT broker	string	Any	ssl://united-manufacturing-hub-mqtt.united-manufacturing-hub:8883
`REMOTE_CERTIFICATE_NAME`	Set to NO_CERT to allow non-encrypted MQTT access, or to USE_TLS to use TLS encryption	string	USE_TLS, NO_CERT	USE_TLS
`REMOTE_PUB_TOPIC`	Remote MQTT topic to publish to	string	Any	ia/factoryinsight
`REMOTE_SUB_TOPIC`	Remote MQTT topic to subscribe to	string	Any	ia

Last modified April 4, 2023: feat: version (75e2d11)