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Capture Flow and Module Events from Node’s local MQTT Broker

Each Node includes a built-in MQTT Broker that can be used to expose data from flows, send messages to flows, or facilitate communication between flows. Additionally, the Node automatically publishes Flow- and Module-related events to the broker.

By subscribing to the $crosser/# topic, you’ll receive notifications whenever a flow or module changes its status or state. This not only enables external systems to subscribe to these events but also allows you to build flows that send these events to external systems.

Crosser Tech Tip 88_1

Each flow publishes its own events on a topic named after its flowDefinitionId and every message will have all required information in order to understand the message, such as flowName, version, nodeName and so on.

Crosser Tech Tip 88_2

Flow start event (state change):

Crosser Tech Tip 88_3

Disconnect from OPC UA Server (status change):

Crosser Tech Tips 88

Note: It is not allowed to publish on any topic under $crosser. Clients that try to publish will be disconnected.

About the author

David Nienhaus | Senior Solution Engineer

David is a Senior Solution Engineer at Crosser. He has over 15 years experience working with software integration and digitization projects for critical infrastructure.
His engineering background gives him the understanding and focus needed to solve customer use cases in the most efficient and successful way.