Signal contracts
Metrics need stable names, dimensions and units before visualisation begins. Throughput may mean accepted events, completed transactions or raw ingress; the dashboard should use the definition that matches the decision an operator must make.
A freshness marker separates a healthy low-volume period from a broken pipeline. Collection time and display time should remain distinct so delayed batches do not appear current.
- Document source, unit, window and owner for every signal.
- Carry event time and ingestion time through the pipeline.
- Limit dimensions to values with clear operating use.