Posts

Stop Node.js Memory Leaks: A Practical Step-by-Step Guide to Diagnose, Fix, and Prevent Them

Intro — why this matters: Memory leaks in Node.js services are stealthy. They slowly increase resource usage, cause GC storms and latency spikes, trigger OOMKilled events in Kubernetes, and ultimately lead to outages and engineering firefights. This guide gives a production-safe, end-to-end playbook to detect a nodejs memory leak, capture heap snapshot nodejs evidence, analyze retained paths, fix common patterns, and add CI and observability to prevent regressions. TL;DR Checklist Quick triage: compare RSS vs heapUsed , inspect GC logs ( --trace-gc ), and check OOMKilled events. Low-impact probes in prod: small heapdump via heapdump on signal or sampling profiler (Clinic) — avoid long blocking operations. Reproduce locally: traffic replay, synthetic load, same Node flags ( --max-old-space-size ). Capture artifacts: heap snapshots, CPU profiles, flamegraphs, and trace-gc output. Analyze: find dominating objects, retained paths, and closure leaks. Fix with concrete ...

How to Profile and Fix Performance Issues in Asyncio Apps: A Practical Guide for Developers

How to Profile and Fix Performance Issues in Asyncio Apps: A Practical Guide for Developers Asyncio apps are powerful: they let you handle thousands of concurrent connections on a single process. But when latency, p95/p99 spikes, or memory growth appear, debugging feels like chasing ghosts — tasks are suspended and resumed across await points, the event loop is invisible, and traditional profilers can mislead. This guide gives you a production-safe, step-by-step playbook to profile async Python , use low-overhead tools like py-spy , combine sampling with tracing, capture coroutine stacks, and apply practical fixes. You'll get checklists, copy-paste commands, code snippets, and real case studies so you can quickly diagnose async performance and prevent regressions. Why async performance problems are different: common causes and symptoms Event loop fundamentals that matter for performance In asyncio, a single event loop schedules coroutines and callbacks. If any piece of co...

From Chaos to Types: A Step-by-Step Incremental TypeScript Migration for Legacy JavaScript Apps

Image
Hook: You have a sprawling legacy JavaScript codebase, bugs sneaking in at runtime, and new team members who spend days understanding loosely-typed modules. TypeScript promises safety and developer productivity—but a full rewrite is a non-starter. This guide shows you how to perform an incremental TypeScript migration that minimizes risk, delivers early wins, and can be measured like a product. Why migrate incrementally Business & engineering benefits Incremental TypeScript migration delivers both tactical and strategic wins: Reduce runtime bugs by catching type errors at compile time. Improve developer onboarding—types are documentation that IDEs use. Make refactors safer and faster; fewer regressions means faster feature delivery. Lower long-term maintenance costs; teams spend less time debugging subtle API mismatches. Framing the migration as a program with measurable KPIs (type coverage, PR velocity, defects) makes it easier to gain stakeholder buy-in....

Ship Insights, Not Rewrites: A Practical Guide to Adding Lightweight Observability to Legacy Monoliths

Short TL;DR: You don’t need a rewrite to get useful telemetry. Start with structured logging and correlation IDs, add a small set of Prometheus metrics, then incrementally add OpenTelemetry traces with sampling. Use a lightweight stack (Grafana + Loki + Tempo + Prometheus) and a 30/60/90 plan to measure impact and expand. This post gives a pragmatic, low-risk playbook with copy‑paste examples and rollout advice so your monolith starts producing actionable insights within days. Why observability matters for legacy monoliths — common pain points and what to expect Legacy monoliths are everywhere: years of business logic, tight coupling, and brittle deployments. When incidents happen you often face long mean time to identify (MTTI) and mean time to recovery (MTTR), noisy logs, and a poor developer experience. Observability for monoliths gives you three things: Faster incident detection and triage (less frantic log grep). Data to prioritize refactors or targeted service extracti...

How to Become an Irreplaceable Software Engineer in the AI Era

 The skills that will define great engineers when everyone has access to AI "AI isn't replacing software engineers. It's replacing the parts of software engineering that never required deep engineering in the first place." Over the last few years, Artificial Intelligence has transformed software development at a pace few expected. Today, AI can generate code, explain algorithms, write unit tests, review pull requests, generate SQL queries, and even build small applications from a simple prompt. Naturally, this has led to an uncomfortable question for many developers: "Will AI replace software engineers?" The short answer is no . The better question is: "What kind of software engineer will remain valuable when everyone has access to AI?" That question has a much more interesting answer. Throughout the history of technology, new tools have consistently changed how engineers work without changing why they are needed. High-level programming languages...