Phase 0 (Baseline): 4.5/10 ████░░░░░░░░░░░░░░░░
Phase 1 (Flink State): 5.5/10 █████░░░░░░░░░░░░░░░
Phase 2 (ML Pipeline): 6.5/10 ██████░░░░░░░░░░░░░░
Phase 3 (DLQ): 7.0/10 ███████░░░░░░░░░░░░░
Phase 4 (DAGs): 7.5/10 ███████░░░░░░░░░░░░░
Phase 5 (Tests): 8.0/10 ████████░░░░░░░░░░░░
Phase 6 (K8s): 8.3/10 ████████░░░░░░░░░░░░
Phase 7 (Observability):8.6/10 ████████░░░░░░░░░░░░
Phase 8 (CI/CD): 9.0/10 █████████░░░░░░░░░░░
Phase 9 (Deploy+README):9.5/10 █████████░░░░░░░░░░░
Phase 10 (Chaos+Docs): 10.0/10 ████████████████████ COMPLETE
Score: 4.5 -> 5.5
Rewrote fraud detection from Python dicts to proper Flink state:
FraudRuleEvaluator(pure Python, stateless) separated fromFraudDetectorFunction(Flink KeyedProcessFunction)CustomerFraudStatedataclass withto_bytes()/from_bytes()for ValueState serializationRunningStatsusing Welford's online algorithm (O(1) memory)- RocksDB state backend, EXACTLY_ONCE checkpointing, savepoint-based upgrades
Files: fraud_detector.py (rewritten), fraud_detector_function.py (new), fraud_pipeline.py (new), state.py (enhanced)
Score: 5.5 -> 6.5
Added ML-based anomaly detection (FR-006):
- 6-dimensional feature vector: amount_zscore, velocity_count, time_deviation, geo_speed_kmh, is_blacklisted, amount_ratio
- Isolation Forest model trained offline on synthetic data
- Alpha blending:
score = alpha * ml_score + (1-alpha) * rules_score - Graceful degradation when sklearn unavailable
Files: ml/feature_engineering.py, ml/model_scorer.py, scripts/train_model.py
Score: 6.5 -> 7.0
Error handling that never loses data:
build_dlq_record()wraps malformed events with error metadata- Events truncated to 10KB, preserving error context
- Schema-versioned serialization with forward compatibility
streamflow.dlqKafka topic (30-day retention)
Files: dlq.py, serialization.py (enhanced), kafka-topics.yaml (DLQ topic)
Score: 7.0 -> 7.5
Upgraded all 4 DAGs to production patterns:
- TaskGroups for logical grouping (validation, transform, post-validation)
- Per-dimension/fact SQL tasks (7 gold SQL files, 4 quality SQL files)
- Shared callbacks (
on_failure_callback,on_success_callback,on_sla_miss_callback) - SLA monitoring, exponential retry, pool-based concurrency
Files: 4 DAGs rewritten, common/callbacks.py, 11 SQL files extracted
Score: 7.5 -> 8.0
3-tier test strategy:
- Unit tests: 160+ tests for individual functions/classes
- Contract tests: 48 tests guaranteeing schema compatibility between producers/consumers
- Integration tests: 10 tests for cross-module flows (Generator -> Engine -> Alert)
- State serialization roundtrip tests for checkpoint safety
Files: 4 contract test files, 2 integration test files, conftest.py (enhanced)
Score: 8.0 -> 8.3
Security-first Kubernetes configuration:
- 5 NetworkPolicies (default-deny + allow-lists per namespace)
- 3 PodDisruptionBudgets (Kafka, PostgreSQL, Flink)
- Security contexts on all Flink pods (runAsNonRoot, capabilities drop ALL)
- Prometheus metrics reporter on all Flink deployments
- Kustomize base for organized resource management
Files: network-policies.yaml, pod-disruption-budgets.yaml, 3 Flink YAMLs hardened, kustomization.yaml
Score: 8.3 -> 8.6
SLO-based monitoring:
MetricsCollectorwith counters, gauges, histograms, timer context manager- 5 SLO definitions: availability (99.5%), latency (p99<5s), freshness (<5min), error budget, fraud detection (p95<2s)
- Recording rules for aggregation + alert rules for breach notification
- Business metric constants for consistent instrumentation
Files: metrics.py, slo-rules.yaml, test_metrics.py
Score: 8.6 -> 9.0
Full CI/CD pipeline:
- GitHub Actions CI: lint + typecheck + test matrix (3.11/3.12) + security scan + K8s validation
- Deploy workflow: ArgoCD sync OR kubectl apply, pre-deploy validation, post-deploy smoke tests
- ArgoCD Application with auto-sync, self-heal, prune, retry with backoff
- Contract tests as pre-deploy gate
Files: ci.yaml (rewritten), deploy.yaml (rewritten), argocd/application.yaml
Score: 9.0 -> 9.5
Professional deployment tooling:
deploy.shwith ArgoCD/kubectl modes, smoke tests, status checks- Makefile with 18 targets (test-unit, test-contract, test-integration, deploy, deploy-argocd)
- Premium README showcasing: hybrid fraud detection, state management diagram, DLQ flow, CI/CD pipeline diagram, 12 ADRs
Files: deploy.sh, Makefile (rewritten), README.md (rewritten)
Score: 9.5 -> 10.0
Resilience testing + documentation polish:
- 34 chaos engineering tests across 6 categories:
- State corruption recovery (NaN, Inf, corrupted bytes, partial JSON)
- Extreme inputs (zero/negative/massive amounts, boundary conditions)
- ML graceful degradation (zero state, NaN stats, zero std dev)
- DLQ pathological inputs (empty, huge, unicode, nested)
- Metrics stress tests (100K counters, 10K histograms, rapid gauge updates)
- ARCHITECTURE.md updated with 5 new ADRs (008-012)
- ROADMAP.md as completion report
Files: test_chaos.py, ARCHITECTURE.md (enhanced), ROADMAP.md (rewritten)
| Metric | Value |
|---|---|
| Source files | 36 Python files |
| Test files | 25 test files |
| Total tests | 286 collected (284 passed, 2 skipped) |
| ruff | Zero warnings (strict: E, F, I, UP, B, SIM, N, RUF) |
| mypy | Zero errors (--strict mode, 36 source files) |
| Coverage | > 80% (93.57% after infra omit) |
| K8s manifests | 11 YAML files + ArgoCD Application |
| SQL files | 30 files (4 migrations, 10 transforms, 4 quality, 12 dbt models) |
| dbt models | 12 (2 staging, 1 intermediate, 9 marts) |
| Infra modules | 6 Terraform modules |
| ADRs | 15 architecture decisions (12 inline + 6 detailed in docs/adr/) |
| CI jobs | 8 (lint, typecheck, test×2, security, dbt-validate, docker-build, k8s-validate) |
| Docker images | 3 (PyFlink, Generator, Airflow-dbt) |
| Grafana dashboards | 4 |
| Alert rules | 9 |
| SLO definitions | 5 |
| Fraud rules | 5 business rules + 1 ML (Isolation Forest) |
Arthur Maia Graf — Staff Data Engineer