标签：#Ring

So far in this mini-series, we've answered the biggest questions that confuse developers when they first encounter Design Patterns. We've learned: why SOLID isn't the final destination, why recurring design problems exist, why copying code doesn't create good design, what Design Patterns really are, how experienced engineers recognize them, and how every pattern can be understood through its Problem, Intent, Solution, and Consequences . Now it's time to answer one final question before we begin exploring the individual patterns. How should we learn Design Patterns so that we can actually use them in real-world software instead of just recognizing their names? The answer may surprise you. We're not going to learn Design Patterns the way they're usually taught. The Traditional Way of Learning Design Patterns Open almost any Design Patterns book or tutorial, and you'll often see something like this. Pattern Name ↓ Definition ↓ UML Diagram ↓ Code Example ↓ Advantages ↓ Disadvantages Technically, there's nothing wrong with this approach. But many developers finish reading the chapter and still wonder: "When would I ever use this?" That's because they learned the solution before understanding the problem. It's like learning how to use a fire extinguisher before understanding what kinds of fires it can safely put out. Knowledge without context is difficult to apply. The Way Experienced Engineers Learn Experienced engineers don't begin with the pattern. They begin with the software. They observe where the current design starts struggling. Only then do they search for a better design approach. Their thinking looks more like this. Business Requirement ↓ Design Challenge ↓ Current Design Starts Breaking ↓ Understand Why ↓ Explore Better Design ↓ Recognize a Design Pattern The pattern is never the starting point. It's the result of understanding the problem. The Learning Framework We'll Use Every pattern in this series will follow exactly the same structure. Business Problem ↓

Building a personalization engine for a multi-format content feed, without machine learning, and the testing process that forced us to rebuild it. TL;DR We run a collaborative cultural curation platform (think: user-submitted recommendations for movies, books, games, music, and long-form posts, all mixed into one feed) on a fairly ordinary PHP + MySQL stack. Over about a year we went through two full generations of the feed ranking algorithm. The first version solved the obvious problem (stop being purely chronological) but quietly failed at real personalization. The second version fixed that by rethinking what "user taste" even means, moving scoring out of SQL and into application code, and adding a layer of post-ranking business rules. This post walks through both generations, why the second one had to happen, and how we actually tested and calibrated a feed ranking system without a data science team or an ML pipeline. No exact weights, table names, or formulas below — just the engineering story. The starting problem: one feed, five content shapes Before personalization is even on the table, a multi-format feed has a normalization problem. Movies, books, games, music, and editorial posts live in different tables, with different columns, different publishing cadences, and engagement numbers on completely different scales. "1,000 likes" on a music post and "1,000 likes" on a book review are not the same signal. So the very first architectural decision — before any ranking logic existed — was building a unification layer that maps every content type into a shared shape (type, author, title, cover, category, engagement counters, timestamp) before any scoring happens. Everything downstream depends on that layer being consistent. Generation 1: a weighted ranker living inside a single SQL query The first real version of the algorithm — internally we called it the hybrid model — had a modest goal: get away from a purely chronological feed without building anything resembl

Why Sports Data Is Harder Than Most People Think Building believable cross-era simulations turned out to be less about the engine and more about the data underneath it. Here is what we learned. MicroLeague Dev Blog, Vol. 3 By Eddie Solar When we started building MicroLeague Sports, I assumed the simulation engine would be the hard part. The vision was ambitious enough to justify that assumption. Let fans ask whether the 1996 Bulls beat the 2017 Warriors. Whether the 1985 Bears could slow down Patrick Mahomes. Which Cowboys team was actually the greatest. Teaching software to play those games across eras felt like the mountain. I was wrong about which mountain it was. The engine is hard, but it is a solvable, bounded kind of hard. The data underneath it is a different animal. Like most developers approaching this for the first time, we figured sports data was largely a collection exercise: gather historical teams, player stats, schedules, and box scores, feed it to the model, done. That assumption fell apart almost immediately, and the reason it fell apart is the subject of this article. Sports data is not a collection problem. It is an identity problem. Franchises do not stay the same thing. Players are not one entity. And the historical record does not agree with itself. The Real Problem Is Modeling Identity Over Time Volume 2 covered the era problem: statistics are confounded by the conditions that produced them, so a raw number pulled across decades lies to you. That is a normalization challenge, and it is real. But normalization assumes you already know what you are normalizing. Before you can compare the 1992 Cowboys to the 2023 Chiefs, your system has to have a confident answer to a more basic question: what exactly is a "team," and what exactly is a "player," when your dataset spans a hundred years? Those sound like trivial questions. They are not. They are the questions that ate most of our early engineering time, and getting them wrong quietly corrupts ever

Every new SaaS seems to embed ChatGPT these days. Most AI support solutions rely on third-party platforms, monthly subscriptions, and vendor lock-in. While they're great products, I wanted something different. I wanted complete ownership. I wanted to deploy everything on my own server, use my own OpenAI API key, customize every part of the experience, and embed the widget into any website with a single script tag. So I built my own self-hosted AI support widget using Spring Boot and Vanilla JavaScript. Why I Built It When building small products and websites, I realized that customer support quickly becomes a problem. Users have questions about pricing, features, returns, or simply get stuck. Most developers solve this by integrating services like Intercom, Crisp, or Tidio. Those platforms are excellent, but they also mean: Monthly subscription costs Vendor lock-in Customer conversations stored on third-party platforms Limited customization Another external dependency I wanted something that developers could completely own. The Goal The goal was simple. Build an AI-powered customer support widget that developers can deploy on their own server and integrate into any website in less than a minute. The widget should: Answer customer questions using AI Learn from a custom knowledge base Match the company's branding Store conversation history Allow human handoff Be easy to deploy Require only one script tag to embed Technology Stack Java 17 Spring Boot 3 Spring Security Spring Data JPA Thymeleaf Vanilla JavaScript H2 Database (MySQL supported) OpenAI API Architecture The overall architecture is intentionally simple. Visitor │ ▼ AI Chat Widget (Vanilla JavaScript) │ ▼ Spring Boot REST API │ ▼ OpenAI API │ ▼ Database (H2 / MySQL) Keeping the frontend framework-free makes the widget lightweight and easy to embed into virtually any website. One-Line Integration Adding the widget to a website only requires a single script. <script src="/widget/widget.js" data-api-base=""></sc

Instacart introduced Blueberry, an AI-assisted incident response system that helps on-call engineers investigate production issues faster. It combines AI agents, operational data, and historical incident knowledge to generate grounded root cause hypotheses in Slack. It uses parallel subagents, MCP integrations, and incident history to reduce investigation time while keeping engineers in control. By Leela Kumili

Artificial intelligence is rapidly changing how engineering teams respond to production incidents, offering the ability to summarize incident channels, analyze unfamiliar code, suggest remediation steps, generate pull requests, and increasingly assist with diagnosis. By Craig Risi

In today's digital world, businesses face the challenge of developing, deploying, and scaling applications faster and more efficiently. One of the key technologies supporting this transformation is container technology. What are Containers and Why Are They Important? Containers allow applications to be packaged into lightweight, self-contained, and portable units that can run consistently in any environment—from a local development machine to a cloud platform. This reduces dependencies and significantly simplifies application deployment and scalability. Unlike virtual machines (VMs), containers share the operating system kernel, making them more resource-efficient. This leads to higher efficiency and allows businesses to run more applications on the same infrastructure. Introduction to Kubernetes: Orchestration of Containers While containers represent a revolutionary approach to developing and running applications, it’s not enough to simply have containers. Once applications consist of dozens or hundreds of containers, managing, orchestrating, and scaling them becomes critical. This is where Kubernetes comes in. Kubernetes is the world’s most widely used container orchestration platform. It enables the automatic deployment, scaling, and management of containerized applications in clusters. With Kubernetes, companies can ensure their applications are always available, automatically recover from failures, and roll out new versions without downtime. Azure Kubernetes Services (AKS): Kubernetes in the Cloud Azure Kubernetes Services (AKS) is Microsoft’s fully managed Kubernetes solution. With AKS, businesses benefit from simplified Kubernetes deployment by offloading infrastructure management to Microsoft. This means you can focus on developing and scaling your applications while AKS simplifies the management and maintenance of Kubernetes clusters. Benefits of AKS: Fully managed: AKS takes care of the management and patching of Kubernetes, allowing businesses to focus on

Introduction As software applications grow in size and complexity, managing object creation becomes challenging. Creating objects directly using constructors can result in tightly coupled code that is difficult to maintain and extend. The Factory Method Design Pattern solves this problem by separating object creation from object usage. It provides a flexible and reusable approach for creating objects, making applications easier to modify and scale. What is the Factory Method Design Pattern? The Factory Method Design Pattern is a Creational Design Pattern that provides an interface for creating objects without specifying their exact classes. Instead of directly instantiating objects using the new keyword, a factory class creates and returns the required object. Definition Factory Method Design Pattern: A creational design pattern that defines an interface for creating objects while allowing subclasses or factory classes to decide which object to instantiate. Why Do We Need It? In traditional programming: The client creates objects directly. Code becomes tightly coupled. Adding new object types requires modifying existing code. Maintenance becomes difficult. The Factory Method pattern solves these problems by centralizing object creation inside a factory class. How It Works The client requests an object from the factory. The factory checks the requested type. The appropriate concrete object is created. The factory returns the object to the client. The client uses the object without knowing how it was created. Java Example interface Shape { void draw(); } class Circle implements Shape { public void draw() { System.out.println("Drawing Circle"); } } class Rectangle implements Shape { public void draw() { System.out.println("Drawing Rectangle"); } } class ShapeFactory { public Shape getShape(String type) { if(type.equalsIgnoreCase("Circle")) return new Circle(); if(type.equalsIgnoreCase("Rectangle")) return new Rectangle(); return null; } } public class FactoryPatternDem

Understanding the Prototype Design Pattern in Java Introduction When developing software, there are situations where creating a new object from scratch is expensive or time-consuming. For example, an object may require complex initialization, database access, or extensive configuration. In such cases, instead of creating a new object every time, we can duplicate an existing object. This is where the Prototype Design Pattern becomes useful. The Prototype Design Pattern is one of the Creational Design Patterns in Java. It allows developers to create new objects by cloning existing ones rather than instantiating them using constructors. What is the Prototype Design Pattern? The Prototype Design Pattern creates new objects by copying an existing object, known as the prototype. This approach improves performance by avoiding repeated initialization and allows developers to create multiple similar objects efficiently. In Java, cloning is commonly implemented using the Cloneable interface and overriding the clone() method. Why Use the Prototype Pattern? The Prototype Pattern offers several benefits: Reduces the cost of object creation. Improves application performance. Simplifies the creation of complex objects. Avoids repeated initialization code. Makes object creation more flexible. Real-World Example Imagine an online shopping application where thousands of product objects share similar properties. Instead of creating every product from scratch, the application can clone a prototype product and modify only the required attributes such as name or price. Other real-world examples include: Document templates Game characters Employee records Vehicle configurations Graphic design objects UML Structure The Prototype Design Pattern generally includes: Prototype Interface – Declares the clone operation. Concrete Prototype – Implements the cloning functionality. Client – Creates new objects by cloning existing prototypes. Java Implementation Step 1: Create the Prototype Class cla

In modern Data Engineering, there is an unspoken fetish for "Real-Time." If you ask any business stakeholder how fast they need their dashboard to update, the default answer will always be: "As fast as possible." This drives well-intentioned engineers to design incredibly complex architectures. We spin up Kafka clusters, implement Flink, and wrestle with latency, late-arriving data, and tumbling windows. All to have data flowing in milliseconds. But the harsh reality is that the vast majority of companies are building Ferraris just to sit in rush-hour traffic. 1. The Actionability Gap (The Golden Question) The biggest mistake when choosing a streaming architecture isn't technical; it's a business mistake. Before implementing real-time pipelines, the only question that matters is: "Does the company have the operational capacity to make a decision in milliseconds?" If you are building a credit card fraud detection system or a live e-commerce recommendation engine, yes, every millisecond counts. But if the data is feeding a financial dashboard that the executive board only reviews during their Monday morning meeting, updating that screen every second is a colossal waste of money and effort. Real-time data has zero value if the human action is batch. 2. The Hidden Complexity and the Cloud Bill Batch processing is forgiving. If a pipeline fails at 3 AM, you trigger a rerun, and by 8 AM, everything is fine. Batch is cheap, predictable, and easy to debug. Streaming, on the other hand, is unforgiving. Handling application state, event duplication (exactly-once semantics), out-of-order events, and sudden traffic spikes requires a senior engineering team dedicated solely to keeping the infrastructure alive. Furthermore, the cloud bill for 24/7 continuous processing is orders of magnitude higher than spinning up your compute clusters on a schedule. 3. "Micro-Batch" Solves 99% of Your Problems There is a perfect middle ground that the hype industry tries to ignore: the micro-ba

Dumanshu Goyal discusses optimizing data layers for low-latency workloads like AI feature stores. Drawing lessons from NASA's Space Shuttle, he explains how proxy architectures introduce hidden CPU costs, elevated tail latencies, and blast-radius risks. He demonstrates how direct-access Valkey architectures achieve microsecond latency, improve resilience, and slash infrastructure costs. By Dumanshu Goyal

AI workflows have two needs that trade off directly. Running reliably in production requires persisting and distributing every step so it survives crashes, deploys, and restarts. But that same machinery is what makes runs too heavy for the fast, throwaway loop you need to check an LLM's output quality. The properties that buy durability are the ones that kill iteration speed. By Mateus Moury

Vercel Labs has introduced Zero, an experimental systems programming language aimed at AI rather than human users. It employs unique features like a specific toolchain contract and structured error messages. Reaching version 0.3.4, it compiles to native binaries for major operating systems. The language prioritizes size, speed, and agent usability, though it is still in development. By Daniel Curtis

Use a kill switch inside the checker when your uptime probes start amplifying an incident — one feature flag, read on every tick, that can disable the noisy checks and stop the retries at the source. Reach for tuned backoff and jitter instead when the retry storm stays inside a single process and never fans out onto a dependency somebody else is paging for. Both are cheap to build. Only one of them lets you quiet a polling client while its target is already on fire. I run cron and queue infrastructure, so most of my pages arrive as either "the job didn't run" or "the job ran four times." Health checking sits in the same family of problems: a small, frequent, automated request that multiplies badly when something upstream changes shape. What follows is the runbook I settled on after a fleet of pollers turned a non-incident into a real one — the failure mode, where the switch belongs, the implementation, and how to verify the flip before you walk away from the terminal. What actually turns a polling client's uptime checks into a retry storm? Amplification. A single check is one request every 15 or 30 seconds, which nobody notices; a fleet of checks with retries layered on top is a synchronized load generator pointed at whatever you decided was important enough to monitor. The math is unkind. Take 40 instances, a 5s interval, and 3 retries per failed attempt, and a dependency that normally handles a trickle of health traffic suddenly sees a couple thousand requests a minute — all of them arriving at the exact moment it's least able to absorb them. Retries stack on top of the polling interval rather than replacing it, and because every poller sees the same failure at the same time, they all back off together and return together. The Google SRE book calls out this shape under cascading failures, and the load pattern that comes out of it looks nothing like organic traffic: sawtooth spikes, perfectly aligned, growing until something sheds load. The worst one I've dealt wit

🎯 What a “Stacked PR” Is (and Why You’ll Want One) A stacked pull request (sometimes called a stacked PR , stacked diff , or dependent PR ) is a series of PRs that build on top of each other, each one containing a small, logically‑isolated change. main ──► A ──► B ──► C │ │ │ │ │ └─ PR‑C (depends on B) │ └─ PR‑B (depends on A) └─ PR‑A (directly on main) A is based on main . B is based on A (its head). C is based on B , etc. When you eventually merge the stack in order (A → B → C), each change lands cleanly, and reviewers can focus on one cohesive piece at a time. Why Stack PRs? Problem Stacked PR Solution Huge, monolithic PRs that are hard to review & cause long CI times Break the work into bite‑size PRs (e.g., “feature flag”, “data model”, “UI”) Inter‑dependent changes (e.g., a new API + its consumer) Each dependent change lives in its own PR, but they still get tested together because they are built on top of each other Rebasing on main constantly drags in unrelated changes Only the bottom PR needs to be rebased onto main ; the rest stay on top of it Need to ship part of a larger change early Merge the first PR in the stack; the rest stay pending until they’re ready CI resources Only the bottom PR runs the full suite against main ; higher PRs can run a lighter subset because they already passed lower‑level tests 📦 The Landscape of Tools (as of 2026) Tool / Service Key Features Installation / Setup Typical Workflow ghstack (GitHub CLI plugin) - Creates stacked PRs automatically from a series of commits. - Handles base‑branch updates, resolves merge conflicts, and can re‑stack after rebases. - Works with GitHub's GraphQL API, so you get “dependent PR” links in the UI. pip install ghstack (or brew install ghstack ). Requires a personal access token with repo scope. bash git checkout -b feature/stacked\n# create many commits …\nghstack push\n# later, after rebasing on main\nghstack rebase . | | GitTown (aka git-town ) | - git town ship can ship a stack of dependent br

After Uber and Waymo ended their partnership in Phoenix earlier this year, experts and robotaxi watchers wondered whether the companies' improbable bromance was fraying. Not so, Uber CEO Dara Khosrowshahi said today. The two companies are committed to continue working together in Atlanta and Austin, and the partnership remains "very strong." "Waymo is a very […]

A Deep Dive into the Memory Model From Source Code to Machine Instructions A five-part journey through compilers, executables, virtual memory, and the CPU Introduction: What Really Happens When Code Runs Consider a simple C program: include <stdio.h> int value = 10; int add(int a, int b) { return a + b; } int main() { int x = 5; int result = add(x, value); printf("%d", result); return 0; } Most programmers look at this and see only the visible outcome: 5 + 10 = 15 But behind that single printed number lies a much deeper story. Where does the data actually live? Who moves it from one place to another? How does the CPU find the instructions it needs to run? And how does the result finally make its way to the screen? Answering these questions means understanding a concept that many programmers use daily but rarely examine closely: the memory model. What Is a Memory Model, Really? Ask most developers what a "memory model" means, and the answer usually comes back in two words: stack and heap. That answer isn't wrong - it's just incomplete. A memory model is really a description of five things at once: How data is stored How data is accessed How long data exists Who is responsible for managing that lifetime How different parts of a system communicate through memory A program never leaps directly from C source code into RAM. Several distinct layers sit between the two, each one translating the layer below it into something the layer above can reason about. This article walks through all of them, one at a time, and then reassembles the full picture. The Four Layers, at a Glance Layer What It Deals With Typical Concepts 1. Programming Language Human-readable code scope, lifetime, ownership 2. Compiler Translating code to instructions registers, optimization, assembly 3. Operating System Running the program as a process virtual address space, .text/.data/.bss 4. CPU Architecture Executing raw instructions registers, cache, pipeline, ALU The rest of this article follows a sing

"A Trie isn't designed to store words. It's designed to make finding everything that shares the same beginning incredibly efficient." In the previous article, we explored a different kind of software problem. Some systems don't search using complete values. Instead, users provide only part of the information they know. The system must immediately suggest possible matches. Once you recognize that requirement, another question naturally follows. How should the system organize data so prefix searches become fast and natural? This is exactly the problem a Trie solves. Think About a Dictionary Imagine opening a physical dictionary. Suppose you're looking for the word: Application Do you start reading from page one? Of course not. You first go to the words beginning with: A Then you narrow further. Ap Then: App Every additional letter reduces the search space. A Trie works in a very similar way. Instead of repeatedly searching through every word, it follows the characters one by one. What Is a Trie? A Trie is a tree-like data structure where each node represents a character. Words that begin with the same characters share the same path. Consider these words. car card care cart A Trie stores them like this. Root ↓ c ↓ a ↓ r ├── end ├── d → end ├── e → end └── t → end Notice something interesting. The prefix: car is stored only once. Every longer word simply continues from that shared path. Every Data Structure Answers a Different Question By now we've seen several data structures, each solving a different design problem. A HashMap asks: Where is this exact object? A Heap asks: Which item has the highest priority? A Queue asks: Which task should happen next? A Stack asks: What is the current working context? A Trie asks: What begins with these characters? Choosing the right data structure starts with identifying which question your software needs to answer. Inserting a Word Imagine inserting: cat The Trie creates a path. Root ↓ c ↓ a ↓ t Now insert: car The beginning alread

TL;DR: Grafana Agent reached End-of-Life on November 1, 2025 and has been replaced by Grafana Alloy. Alloy consolidates Agent's Static mode, Flow mode, and Kubernetes Operator into a single collector built on the OpenTelemetry Collector while maintaining native support for Prometheus and Loki. If you're using Flow mode, migration is relatively straightforward. If you're using Static mode, the migration process will involve reviewing and testing the converted configuration. Before switching over, verify relabeling rules, recheck resource usage, and confirm that Prometheus and Loki are receiving the same data and labels as before. If you're still running Promtail, it's worth migrating both to Alloy at the same time since Promtail is also End-of-Life. If you deployed Grafana Agent a couple of years ago, there's a good chance you haven't thought about it since. It quietly collects metrics, ships logs, and generally stays out of the way. What you may not realize is that Grafana Agent reached End-of-Life on November 1, 2025. That includes Static mode, Flow mode, and the Kubernetes Operator. Grafana Labs has stopped creating bug fixes, security patches, and official support. If you're still running it, your collection layer is probably still performing normally, but is now unsupported. That doesn't necessarily mean it will stop working tomorrow, plenty of unsupported software continues running for years. It does mean you're taking on the risk yourself, especially as the rest of your monitoring stack continues to evolve. This article covers why Grafana Labs replaced Agent with Alloy, what actually changes during the migration, and where people tend to run into problems. Why Grafana Agent was deprecated One of the biggest issues with Grafana Agent is that it was essentially three agents, not one product: Static mode, which used YAML and looked similar to Prometheus. Flow mode, which introduced a component-based configuration using River. The Kubernetes Operator, which manage

TL;DR If you're a five-person startup shipping a Node.js API and you want a metrics dashboard by Friday, send your telemetry to a managed backend and keep only the instrumentation layer inside your own repo. The alternative — standing up a time-series database, an object store for long-term blocks, and a dashboard service — puts three more components on an on-call rotation that hasn't earned its first SLO yet. Settle the wire format now and treat the backend as a config line you can change later. I own the platform team's roadmap, which in practice means I'm the person who defends the monitoring bill in a budget review and also the person who gets paged when a disk fills at 03:00. Those two jobs pull in opposite directions, and most of the advice online is written by people who only hold one of them. Usually the pager wins the argument. Should a startup run its own metrics stack, or pay for a managed dashboard? Start with capacity, because that's the step everyone skips before signing anything. A moderately instrumented Node.js API — say 40 HTTP routes, two queue workers, default runtime and event-loop metrics, one latency histogram with ten buckets — sits somewhere around 3,000 to 8,000 active series per process. Multiply by replicas. Multiply again by every environment you keep alive, including the staging cluster nobody admits to. You are at 50k active series before a single engineer has written a custom counter, and a self-hosted scraper will chew through that on a 2 GB VM without noticing. It will still be fine at 500k. Past a few million active series you're into sharding, remote storage, and a retention argument with whoever pays for object storage — that's the point where the self-hosted route stops being free and turns into a project with a headcount attached. None of that work is hard. It's just never zero. Dimension Self-hosted stack Managed metrics backend Time to first dashboard 1–3 days under an hour Who owns retention you, plus the storage bill vendor