What if your Kubernetes cluster simply refused to run unsigned images? I spent some time experimenting with enforcing image provenance in a small Kubernetes setup using MicroK8s. The idea was simple: Only container images with valid cryptographic signatures are allowed to run in the cluster. For this I used: GitLab CI/CD (build + signing pipeline) Cosign / Sigstore (image signing) Kyverno (admissi
💡 Problem: How do we ensure that a class has only ONE instance throughout the application? 💡 Common Use Cases: Logger Configuration Manager Database Connection 💡 Approach: We restrict object creation and provide a global access point. 💡 Key Idea: Private constructor Static instance Public method to access it 💻 Java Example: private static Singleton instance; privat
The drift problem Every project that ships a translated README has the same lifecycle: Someone writes README.md in English. A contributor opens a PR with README.zh.md. Great. Three months later, English has six new sections. Chinese has the original. A second translator opens README.es.md. Spanish gets translated from… which version? The current README.md? Or README.zh.md, by accident, because t
Apache Stateful Functions is one of the quietly powerful frameworks in the Flink ecosystem - durable per-key state, exactly-once messaging, polyglot remote functions, all on top of Apache Flink. It's also been functionally dormant since October 2024, and it doesn't run on Flink 2.x. We needed it on Flink 2.x. So we maintained the continuation: kzmlabs/flink-statefun. This post is the why and the h
How We Improved Payment System Throughput by 25% Using Apache Kafka at a Fortune 500 FinTech By Disha Sune — Java Backend Engineer | Spring Boot | Kafka | AWS | Fiserv At Fiserv, our payment processing platform handled millions of financial transactions daily for 600+ enterprise clients including McDonald's, Google, and Domino's. As transaction volumes grew, our legacy synchronous REST API archi
Hello Developers! 👋 Most developers today pick a side: Let’s talk about combining C++ and JavaScript—the ultimate hybrid stack for high-performance applications. 👇 1. The Core Engine (C++) ⚙️ 2. The Browser Bridge (WebAssembly) 🌉 3. The Cinematic Experience (Vanilla JS + UI/UX) ✨ The Takeaway 🎯 Keep optimizing, keep building! 💻✨ ~ Ujjwal Sharma | @stackbyujjwal About the Author 👨💻 Ujjwal
Most teams I have worked with have one auth test in their suite. It looks like this: test('valid token verifies', () => { const token = signSync({ sub: 'user-1', aud: 'api://backend' }, secret); const result = verify(token, options); expect(result.valid).toBe(true); }); That test is fine. It is also a smoke test, not a regression suite. It catches the case where verification is completely b
The on-call alert at 02:14 said auth_5xx_rate spiked from 0.01 to 31.4. Not a deploy window. Not a traffic spike. Just thirty-one percent of authenticated requests failing for ~four minutes, then back to baseline. The cause was a JWKS rotation on the issuer side. New keys came in. Old keys went out. Caches in our service didn't refresh fast enough. Tokens signed with the new key were rejected beca