Correlation data

Every message in Fluxzero includes correlation metadata that enables traceability across applications, clients, and handlers. This correlation data is automatically added by the Fluxzero SDK to the Metadata of published messages.

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Metadata key	Description
$applicationId	Unique identifier of the Fluxzero application instance that produced the message.
$clientId	Identifier of the client (SDK instance) within the application.
$clientName	Human-readable name of the client, typically derived from configuration or environment.
$consumer	Name of the consumer that handled or tracked the message.
$tracker	Identifier of the tracker that processed the message batch.
$correlationId	Unique correlation ID shared by all messages related to the same logical operation.
$traceId	Identifier used for distributed tracing across services and applications.
$trigger	Identifies the triggering message or context that caused this message to be published.
$triggerType	The type of the triggering message or context (e.g., command, event, schedule).
$invocation	Identifier for a specific invocation or execution path, useful for replay and debugging.
$msDelay	The delay (in milliseconds) applied before a scheduled message was executed.

Note

Flux reserves $ as a prefix for metadata property names. You are allowed to use the $ prefix for your own metadata properties, but this is unsupported and therefore we recommend using a different prefix to avoid conflicts with Fluxzero’s internal metadata properties. Supported exception: use the SDK-provided trace helpers (for example Metadata.withTrace(...)) which intentionally write $trace.* keys.

See CorrelationDataProvider for the full list of metadata properties that are propagated by default.

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Tip

Correlation metadata makes it easy to trace messages end-to-end across multiple services, handlers, and time windows.