KIP-933 — Publish metrics when source connector fails to poll data

Discussion ConnectMetrics

Adds source-record-poll-error-total and source-record-poll-error-rate metrics at task granularity in kafka.connect:type=task-error-metrics to track failures in SourceTask#poll(). No existing metric distinguished between failures during polling from the source system versus failures when producing to Kafka, forcing operators to rely on log inspection.

Details