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MQTT Transport

Syncs over a standard MQTT broker (e.g. Mosquitto). Suitable for WiFi or cellular connectivity. No infrastructure limitation on bandwidth.

Topic structure​

ara/{network_id}/presence/{node_id}    ← retained heartbeat
ara/{network_id}/handshake/{node_id}   ← vector clock broadcast
ara/{network_id}/changeset/{node_id}   ← outbound changesets

All nodes on the same network_id automatically discover and sync with each other.

Go​

node.AddTransportMQTT(ara.MQTTConfig{
    BrokerURL: "tcp://192.168.1.100:1883",
    NetworkID: "my-network",
})

Android​

node.addTransportMQTT(
    brokerUrl = "tcp://192.168.1.100:1883",
    networkId = "my-network",
)

Running a broker​

For development, run Mosquitto locally:

# Docker
docker run -p 1883:1883 eclipse-mosquitto

# macOS (Homebrew)
brew install mosquitto && mosquitto

OpenTelemetry​

When using MQTT, you can also enable trace export to an OTel collector on the same host. The Android example app derives the collector address from the broker hostname:

node.initOTLP("$brokerHost:4317")