Overview

Deterministic Kafka replay for debugging event windows safely.

Lighthouse is being rebuilt from a legacy monitoring dashboard into a Kafka replay workbench. The current implementation already supports a local sample cluster, external Kafka and Confluent Cloud connection settings, a Prometheus-backed dashboard, and a replay CLI with dry-run preview, timestamp-window replay, throttling, and replay traceability headers.

Run locally

Start the full demo stack with Kafka, Prometheus, and the app.

npm run docker:sample

Preview a replay

Inspect a bounded slice without producing anything.

npm run replay:cli -- --source orders --destination orders-replay --partition 0 --start 10 --end 25 --dry-run

Run a replay

Copy one closed offset range or resolved time window into a sandbox topic.

npm run replay:cli -- --source orders --destination orders-replay --partition 0 --start 10 --end 25

What Exists Today

Prometheus-backed Kafka dashboard in Next.js
Local three-broker Kafka sample stack in Docker Compose
Kafka metrics exporter for local Kafka and Confluent Cloud
Replay CLI with offset-range and timestamp-window replay, throttling, dry-run preview, and metadata headers
Replay job API for persisted replay creation, preview, and start
Replay workspace in the application shell for draft creation and monitoring
CI for audit, lint, unit tests, build, Docker, and Playwright

Read This First

Getting Started

Choose between the sample cluster, an existing Kafka endpoint, or Confluent Cloud.

Open setup guide

Replay CLI

See the command contract, dry-run mode, and replay header model.

Open replay guide

Replay Jobs

Use the persisted workflow for draft, running, completed, failed, and cancelled jobs.

Open jobs guide

Replay API

Create, preview, start, cancel, and inspect replay jobs through HTTP endpoints.

Open API guide

Replay UI

Use the browser workflow for draft creation, preview, and job monitoring.

Open UI guide

Architecture

Understand the current dashboard flow and the replay execution path.

Open architecture guide

Operations

Use the runbook for health checks, troubleshooting, and local verification.

Open operations guide

MVP Acceptance

Review the end-to-end checks that prove the replay MVP before alpha hardening.

Open acceptance guide

The static documentation site is meant for GitHub Pages deployment. The source lives in site/ and the workflow publishes it on pushes to main or by manual dispatch.

For repo-facing docs, see README.md and the markdown files in docs/.