TTL Lock Expired: How a Fencing Token Stops an Old Worker
On a safe model, we show why lease expiration does not stop an old process and how a monotonic fencing token prevents it from overwriting the new owner's result.
Денис
8 minViews0
COMMUNITY AUTHOR
Денис
One point for every published article.
Stories by this author
Batch API Returned 200: How Not to Lose Errors for Individual Items
Check every element of the batch response: detect missing results, avoid resubmitting successful SKUs, and safely resume only temporarily failed operations.
Денис
9 minViews1
External API Returns Errors: Testing Circuit Breaker Without Cascade Timeouts
Practical guide to circuit breaker: three technical failures trip the breaker, requests stop reaching the external API, a failed probe extends the pause, and a successful one restores normal operation.
Денис
10 minViews1
Webhook Signature Is Valid: How to Stop a Replay of a Correct Request
We analyze a replay attack on a correctly signed webhook: signing the timestamp and nonce, verifying the time window, and showing why worker local memory loses protection after a restart.
Денис
8 minViews3
One Limit for Multiple Workers: Testing the Shared Token Bucket API
On a deterministic model, we compare local and shared token buckets: two workers receive four 429 responses with local limits, while a single shared limiter distributes eight requests without exceeding the limit.
Денис
8 minViews2
API Delta: How to Prevent Double-Counting of Product Quantities
On the tested model, we compare the change in product quantity against a record of its absolute value. A single operation_id prevents the same command from being applied twice, while version checking rejects stale snapshots after new product movements.
Денис
9 minViews3
WordPress 7.1.4: What to Check Before an Urgent Update
On October 28, WordPress released 7.1.4 with security fixes. We examine the affected branches, the safe update sequence, and acceptance criteria for sites, stores, and integrations.
Денис
5 minViews3
Message Fails Again: Checking the Dead-Letter Queue and Safe Return
On an isolated SQLite model, we check the retry limit, move persistent errors to a dead-letter queue, handle rollback on failure between insert and delete, and perform a single return of the corrected message.
Денис
11 minViews3
Order Saved, but Webhook Not Sent: Checking the Transactional Outbox
We examine the transactional outbox using a safe model: the order and outgoing event are recorded in a single transaction; failures before and after sending do not lose the event, and retries use a stable event_id.
Денис
10 minViews3
OAuth Token Expired for Eight Requests: How to Perform a Single Update
We examine single-flight for OAuth: one request updates the access and refresh tokens, others wait for the result, and a token endpoint error does not corrupt the saved pair.
Денис
8 minViews5
Webhook Secret Rotation: Changing Keys Without Stopping Acceptance
Practical guide: accept K1 and K2 only within a limited window, bind the signature to key_id and timestamp, verify HMAC via compare_digest, and disable the old key based on seven test results.
Денис
8 minViews0
JSON Patch test: how not to overwrite a price after someone else's change
Practical guide to RFC 6902: place a test before replace, reproduce fresh and stale prices, verify atomic failure and JSON type differences on CPython 3.12.
Денис
8 minViews5