TraceA

TraceA is a convention used in software observability to label and propagate a trace identifier across components in a distributed system. It serves to connect related events into a single end-to-end trace, enabling developers to follow a request as it traverses services, queues, and databases.

A traceA value, typically a string such as a UUID or hex-encoded hash, uniquely identifies a request trace. It is carried in metadata, commonly in HTTP headers (for example, traceA) or in structured log fields.

A trace consists of one traceA and multiple spans. Each span has a span_id, parent_id, name, start and end timestamps, and attributes. Propagation rules require downstream services to pass the same traceA to ensure continuity, while collectors and exporters gather spans to form a trace tree that represents the path of the original request through the system.

The traceA approach supports troubleshooting, performance analysis, and capacity planning by enabling end-to-end visibility across heterogeneous components and boundaries. It also facilitates correlation between logs, metrics, and traces.

TraceA is not a formal universal standard, but it aligns with common distributed tracing practices and is implemented by many observability tools that support trace identifiers and propagation. Adoption varies by platform and ecosystem, with OpenTelemetry and related tooling providing widely used implementations for trace collection and export.

See also distributed tracing, OpenTelemetry, tracing headers, and observability.