MQTT

Miravo publishes every asset member as an individual MQTT topic. MQTT is enabled by default.

Embedded vs External Broker

Embedded (default)

Miravo starts an embedded aedes broker on port 1883. No external infrastructure required.

miravo start --template smart-factory

External

Connect to an existing MQTT broker:

miravo start --template smart-factory \
  --mqtt-mode external \
  --mqtt-url mqtt://broker.example.com:1883

With authentication:

miravo start --template smart-factory \
  --mqtt-mode external \
  --mqtt-url mqtt://broker.example.com:1883 \
  --mqtt-username user \
  --mqtt-password pass

Topic Structure

Topics follow the Unified Namespace (UNS) pattern derived from the template’s namespace and browse paths:

{enterprise}/{site}/{area}/{line}/{instance}/{member}

Example topics from the smart-factory template:

MiravoWorks/smart-factory/production/line-1/belt-conveyor-001/speed_feedback
MiravoWorks/smart-factory/production/line-1/centrifugal-pump-001/discharge_pressure
MiravoWorks/smart-factory/utilities/compressed-air/air-compressor-001/header_pressure

Payload Format

Each message is a JSON object:

{
  "value": 5.21,
  "timestamp": 1710000000000,
  "quality": "good",
  "unit": "bar",
  "instanceId": "centrifugal-pump-001",
  "model": "centrifugal-pump",
  "dataType": "Double"
}

With metadata: "full", additional fields are included: access, euRange, kind.

Configuration

Option	Env Var	Default	Description
--mqtt-port	MIRAVO_MQTT_PORT	1883	Broker port (0 = ephemeral)
--mqtt-host	MIRAVO_MQTT_HOST	127.0.0.1	Broker bind host
--mqtt-mode	MIRAVO_MQTT_MODE	embedded	embedded or external
--mqtt-url	MIRAVO_MQTT_URL	—	External broker URL
--mqtt-username	MIRAVO_MQTT_USERNAME	—	External broker username
--mqtt-password	MIRAVO_MQTT_PASSWORD	—	External broker password
--no-mqtt	—	—	Disable MQTT entirely

Advanced Settings

These can be set via environment variables:

Env Var	Default	Description
MIRAVO_MQTT_DRAIN_BUDGET	16384	Max messages per embedded drain cycle (512-65536)
MIRAVO_MQTT_BATCH_SIZE	2048	Publishes before yielding to event loop (64-16384)
MIRAVO_MQTT_BROKER_CONCURRENCY	500	Aedes internal concurrency (10-5000)

Report by Exception (RBE)

RBE filtering skips publishing when a value has not changed beyond a deadband threshold. Configure in template protocol settings or via the admin API.

Control Transport

When MQTT is enabled, Miravo publishes control topics for monitoring:

Topic	Content
$miravo/<name>/metrics	Engine metrics (published every 5 ticks)
$miravo/<name>/state	Engine state snapshot (published every 30 ticks)
$miravo/<name>/cmd	Send engine commands as JSON
$miravo/<name>/cmd/result	Command execution results

Send commands over MQTT:

mosquitto_pub -t '$miravo/miravo/cmd' \
  -m '{"type":"triggerFault","instanceId":"pump-001","fault":"cavitation"}'

Disabling MQTT

Run with other protocols only (e.g., OPC UA):

miravo start --template smart-factory --no-mqtt --opcua

Or disable at runtime:

miravo adapter disable mqtt