trackeither

Trackeither is a conceptual design pattern in software engineering used to monitor and process two parallel data streams or decision paths within a single framework. It is not tied to a single language or library and is often discussed in contexts such as tracing, analytics, or event processing. The core idea is to maintain two independent tracks, A and B, and to direct events, samples, or messages to one or both tracks based on a classifier or external signal. Both tracks maintain their own state, counters, and logs, enabling side-by-side analysis and auditing.

Implementation typically involves a dispatcher that applies a predicate or routing rule to each incoming event, assigns it to track A or track B, and records metadata such as timestamp, source, and decision. In functional settings, trackeither can be expressed using an Either-like structure, where an event is wrapped as Left or Right, with downstream stages consuming the corresponding branch. Some designs support merging or reconciliation after tracking, to synthesize insights from both streams.

Applications include telemetry for A/B testing, dual-path error handling, performance comparison of two algorithms, and debugging concurrent workflows. Limitations include increased resource use, potential timing or ordering challenges, and the need for careful synchronization when the two tracks interact. See also: Either type, event tracing, telemetry, A/B testing, branch pattern.