asmhatreandClaude Sonnet 5.5
59fcdbe079
Similarity scoring, a 5-minute windowed count that alerts once, and a KTable blocklist join, with the Spring wiring on Spring Boot 4.1.1 and Kafka Streams 4.2.1. Co-Authored-By: Claude Sonnet 5.5 <[email protected]> Claude-Session: https://claude.ai/code/session_01RjfyTgmERTWLqzafu34Cth
1.9 KiB
1.9 KiB
kafka-streams
Companion code for Kafka Streams with Spring Boot 4: Real-Time Fraud Detection with Vector
Similarity on ankurm.com. The whole topology runs under
TopologyTestDriver, so no Kafka broker is needed to run anything here.
| Stack | Version |
|---|---|
| JDK | 25 (Temurin 25.0.4.1+1) |
| Spring Boot | 4.1.1 |
| Spring for Apache Kafka | 4.1.1 |
| kafka-streams / kafka-streams-test-utils | 4.2.1 (what Boot 4.1.1 manages) |
Run it
./scripts/run-all.sh # runs the tests, rewrites output/*.txt
What is where
| File | Role |
|---|---|
FraudTopology |
The topology as plain Kafka Streams code: similarity scoring, 5-minute velocity count, blocklist KTable join |
Embedder |
A hand-built 6-number feature vector and cosine similarity (not a learned model) |
FraudStreamsConfig |
The only Spring wiring: @EnableKafkaStreams plus handing the StreamsBuilder to the topology |
FraudTopologyTest |
Five tests; each one writes the matching output/NN-*.txt |
ContextLoadsTest |
Loads the Spring context with auto-startup=false to show the wiring without a broker |
Captured output
Every file in output/ is written by a test that also asserts it.
| File | Shows |
|---|---|
01-similarity-scores.txt |
Scores for five sample transactions against the 0.98 threshold |
02-similarity-alerts.txt |
Only the fraud-shaped transaction produces an alert |
03-velocity-window.txt |
Six transactions in two minutes give one alert; the next window starts from one |
04-blocklist-table-join.txt |
Join before blocking, after blocking, and after a tombstone |
05-topology-description.txt |
Topology.describe() of the whole graph |
06-spring-context.txt |
The Spring factory bean is wired and not running |
The article carries the explanations; there is deliberately no docs/ folder.