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The Zenoh-MQTT bridge runs on edge devices alongside Edge Core. It connects the local high-performance Zenoh data bus (cyberwave.data) to the cloud MQTT broker, forwarding selected channels in both directions.

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Overview

DirectionSourceDestinationUse case
OutboundZenoh channelMQTT topicInference results, events, health to cloud
InboundMQTT topicZenoh channelWorkflow sync commands from cloud
When MQTT is disconnected, outbound messages are buffered to a persistent file-backed queue and drained in FIFO order on reconnect.

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Quick start

from cyberwave.zenoh_mqtt import ZenohMqttBridge, BridgeConfig

bridge = ZenohMqttBridge(
    config=BridgeConfig(
        twin_uuids=["<twin_uuid>"],
        outbound_channels=["model_output", "event", "model_health"],
    ),
    mqtt_host="<mqtt_host>",
    mqtt_port=8883,
    mqtt_password="<api_key>",
)
bridge.start()

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Default topic mapping

Zenoh keyMQTT topicDirection
cw/{twin}/data/model_outputcyberwave/twin/{twin}/model_outputEdge to Cloud
cw/{twin}/data/eventcyberwave/twin/{twin}/eventEdge to Cloud
cw/{twin}/data/model_healthcyberwave/twin/{twin}/model_healthEdge to Cloud
—cyberwave/twin/{twin}/commands/sync_workflowsCloud to Edge

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Offline queue

When the MQTT connection drops:
  1. Outbound messages are appended to segmented files under CYBERWAVE_BRIDGE_QUEUE_DIR.
  2. On reconnect, the queue is drained in FIFO order before resuming live forwarding.
  3. Queue size is bounded by CYBERWAVE_BRIDGE_QUEUE_MAX_BYTES (default 50 MiB); oldest segments are evicted when the budget is exceeded.

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Configuration

Environment variableDefaultDescription
CYBERWAVE_BRIDGE_ENABLEDfalseMaster switch
CYBERWAVE_BRIDGE_TWIN_UUIDS—Comma-separated twin UUIDs
CYBERWAVE_BRIDGE_OUTBOUND_CHANNELSmodel_output,event,model_healthChannels forwarded to MQTT
CYBERWAVE_BRIDGE_INBOUND_TOPICScommands/sync_workflowsMQTT suffixes forwarded to Zenoh
CYBERWAVE_BRIDGE_QUEUE_DIR/tmp/cyberwave_bridge_queuePersistent queue directory
CYBERWAVE_BRIDGE_QUEUE_MAX_BYTES52428800Max offline queue size (bytes)
CYBERWAVE_BRIDGE_MQTT_QOS1MQTT QoS for bridge messages

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Transition compatibility

Existing direct MQTT paths (cw.mqtt.publish(...)) continue to work unchanged. The bridge is additive — channels published via both Zenoh and MQTT are handled idempotently on the cloud side.