CSC510 Lecture 25

Checkpoint
(20261019)

Transcript

1. CSC 5100 Modern Software Engineering Lecture 25. Checkpoint Dr. Javier Gonzalez-Sanchez javiergs@calpoly.edu www.javiergs.phd ffi o ce: 14 -227
2. Week 11 Completed
3. PR
4. Claude
5. lidar-closest
6. lidar-safety public LidarSafetyLambda() { this( System.getenv("A04_DYNAMODB_TABLE"), System.getenv("A04_S3_BUCKET"), System.getenv("A04_SNS_TOPIC_ARN"), System.getenv("A04_SQS_QUEUE_URL") ); }
7. coordinate-normalizer robot-reachability catch (Exception exception) { System.out.println( "CoordinateNormalizerLambda failure: " + exception.getMessage()); exception.printStackTrace(System.out); return httpResponse(500, "{\"error\":\"Operation failed\"}"); } catch (Exception exception) { return httpResponse(400, "{\"error\":\"Operation failed\"}"); }
8. Agenda
9. Agenda Week 12 Week 13 Week 14 Week 15 Exams Week December 09 Fin l Review a a a a December 11 Fin l Ex m ? December 18 Fin l Project ?
10. Homework
12. Lab 07 1. Structured logging + JUnit JSON verification. 2. CloudWatch observation and application-error discussion. 3–4. Interface + constructor injection + in-memory fake. 5. Controlled failing fake + partial-failure analysis. 6. Bounded retries + recovery/exhaustion tests + idempotency discussion. 7. Full regression test results and GitHub PR evidence. No new AWS resources; no live failure injection; submit code through a PR.
14. (
15. Blueprints VS
16. Blueprints
17. Relationships
18. )
19. Failure Injection
20. JUnit: recovery, exhaustion, and immediate stop Recovery Retry exhaustion Non-retryable Fake fails twice Retryable failure every time Fake throws non-retryable error Third attempt succeeds Propagate exception Propagate immediately assert attempts == 3 assert attempts == 3 assert attempts == 1 Inject a no-op delay so JUnit tests remain fast and deterministic.
21. JUnit: recovery, exhaustion, and immediate stop Recovery Fake fails twice Third attempt succeeds assert attempts == 3 Inject a no-op delay so JUnit tests remain fast and deterministic.
22. Deterministic failure injection — actual Messaging contract Messaging failingMessaging = json -> { throw new RuntimeException("Simulated messaging failure"); }; TemperatureLambda lambda =new TemperatureLambda(fakeStorage, failingMessaging); Local fake only. No SNS outage, AWS credentials, or live failure injection.
23. Step 4: deterministic failure injection Fail twice, then succeed. A controlled test double—not a real SNS failure. public final class FailingPublisher implements EventPublisher { private int attempts; public void publish(String id, String json) { attempts++; if (attempts < 3) throw new TransientPublishException("SNS unavailable"); } public int attempts() { return attempts; } } 16
24. JUnit: recovery, exhaustion, and immediate stop Retry exhaustion Retryable failure every time Propagate exception assert attempts == 3 Inject a no-op delay so JUnit tests remain fast and deterministic.
25. Step 5: bounded retry policy public class RetryingMessaging implements Messaging { public void execute(Runnable operation) { RuntimeException last = null; for (int attempt = 1; attempt <= maxAttempts; attempt++) { try { operation.run(); return; } catch (TransientPublishException e) { last = e; // backoff can be added here } } throw last; } 18
26. Step 6: verify retries with JUnit Verify behavior, not just console output. @Test void transientFailureRecovers() { FailingPublisher publisher = new FailingPublisher(); RetryPolicy policy = new RetryPolicy(3); policy.execute(() -> publisher.publish("id-1", "{}")); assertEquals(3, publisher.attempts()); }
27. JUnit: recovery, exhaustion, and immediate stop Non-retryable Fake throws non-retryable error Propagate immediately assert attempts == 1 Inject a no-op delay so JUnit tests remain fast and deterministic.
28. JUnit: recovery, exhaustion, and immediate stop Recovery Retry exhaustion Non-retryable Fake fails twice Retryable failure every time Fake throws non-retryable error Third attempt succeeds Propagate exception Propagate immediately assert attempts == 3 assert attempts == 3 assert attempts == 1 Inject a no-op delay so JUnit tests remain fast and deterministic.
29. Questions
30. CSC 5100 Modern Software Engineering Javier Gonzalez-Sanchez, Ph.D. javiergs@calpoly.edu Fall 2026 Copyright Notice. These slides are provided exclusively for educational use in CSC 5100 within the California State University system. Redistribution or use for any other purpose is prohibited without prior written permission.