2026 · jordimarsal/kafka-adapter-telemetry

kafka-adapter-telemetry

Event-driven adapter telemetry: a Kafka gateway + hub pipeline with idempotent Oracle persistence, per-adapter health tracking, alerting, and a live SSE mission-control dashboard.

Problem

Fleets of ~90 API adapters across 4 countries need operational visibility: who is DOWN, when did it start, and what already alerted. Built as a personal study of the Open Gateway telemetry problem, end to end.

Highlights

• Hexagonal per service: gateway publishes transit profiles (low/moderate/high/overload), hub persists idempotently by event id.
• Alert rule pinned by tests: 3 consecutive DOWN → exactly 1 alert per episode.
• DLT with retries absorbs duplicate and corrupted JSON without blocking the lane.
• demo.sh proves the whole loop from zero: idempotent counts, single alert, DLT routing.
• 10/10 tasks delivered with Spec-Driven Development; 3 ADRs; diagrams auto-published to GitHub Pages in CI.

Stack

• Java 25
• Spring Boot 4.1
• Kafka
• Oracle
• Flyway
• Testcontainers
• SSE

Metrics

3×DOWN → 1

alert per episode

100%

idempotent inserts

10/10

SDD tasks done