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How I built multi-tenant Row Level Security with Aurora PostgreSQL for a B2B SaaS — H0 Hackathon
I'll be honest: I almost did multi-tenancy the wrong way. When I started building InspectIQ "a SaaS platform for Florida home inspectors" my first instinct was to add a tenant_id column to every table and filter it in the application layer. Every query would have a WHERE tenant_id = :current_tenant clause. Simple, familiar, done. Then I thought about what happens when you forget one. One missing WHERE clause. One endpoint that skips the filter. One inspector sees another inspector's client data. In a home inspection business, that's not just a bug — it's a HIPAA-adjacent nightmare and a trust-destroying moment with your first customer. So I did it properly from day one: Row Level Security at the database layer. What is Row Level Security? RLS is a PostgreSQL feature that lets you define policies directly on tables. When a user queries a table, the policy runs automatically, before your application code even sees the results. You can't forget to apply it. You can't bypass it with a careless JOIN. It's enforced at the lowest possible layer. For a multi-tenant SaaS, this is exactly what you want. How I implemented it Every table in InspectIQ has this pattern: ALTER TABLE inspections ENABLE ROW LEVEL SECURITY ; ALTER TABLE inspections FORCE ROW LEVEL SECURITY ; CREATE POLICY tenant_isolation ON inspections USING ( tenant_id = NULLIF ( current_setting ( 'app.current_tenant_id' , true ), '' ):: uuid ); The FORCE is important — it applies the policy even to the table owner. No superuser backdoor. The tenant context comes from the JWT. When an inspector logs in, their tenant_id is embedded as a custom Cognito claim. The FastAPI middleware extracts it and sets it at the start of every request: await session . execute ( text ( f " SET LOCAL app.current_tenant_id = ' { tenant_id } '" ) ) SET LOCAL scopes the setting to the current transaction. When the transaction ends, it's gone. No leakage between requests. Aurora PostgreSQL Serverless v2 I'm running this on Aurora PostgreSQ
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I Built a Telegram-Inspired Messaging App Out of Boredom — Meet IGram
Sometimes, the best ideas come when you least expect them — like at 2 AM, scrolling through social media with nothing exciting to do. That’s exactly how IGram, my latest side project, came to life. No grand plans, no investors, no pressure — just a spark of curiosity and a desire to build something fun. In this post, I’ll share the story of how IGram started, what it is, the challenges I faced, and what I learned along the way. If you’ve ever wondered what it’s like to build a messaging app from scratch or are just curious about side projects, this one’s for you. HOW IT BEGAN _**A few days ago, stuck in an endless social media scroll loop, I suddenly thought, “Why not build my own messaging app?” Not to compete with the giants like Telegram or WhatsApp, and certainly not because I had a startup idea or funding. Simply because I wanted to see how far I could take it. That spontaneous idea turned into IGram, a project born purely out of boredom and a hunger to learn. What Is IGram? IGram is a modern messaging app inspired by platforms like Telegram and Discord. But it’s not a clone. Instead, it’s designed to feel fast, smooth, and enjoyable—an experience I wanted to craft from the ground up. It’s my personal challenge and learning experiment, built solo and fueled by the excitement of creating something new. Features You’ll Find in IGram Even though it started as a simple idea, IGram has grown to include a solid set of features: One-to-one messaging Group conversations Channel support Message reactions, editing, and deletion Reply and message forwarding Search functionality Dark and light themes Responsive design and mobile-friendly layout User profiles and modern UI animations Every feature is designed to keep the app feeling smooth and responsive, because the user experience matters just as much as the functionality. The Biggest Challenge: User Experience Surprisingly, writing the code wasn’t the toughest part—it was designing how everything flows and feels. Modern
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I Built a $3 Rubber Ducky
If you've ever watched a hacker movie and seen someone plug in a USB and own a machine in seconds — that's not Hollywood magic. That's a Rubber Ducky. And I built one for under ₹150. Here's exactly how I did it, what it taught me, and why every security student should build one. What Even Is a Rubber Ducky? A Rubber Ducky is a USB device that pretends to be a keyboard. The moment you plug it in, the operating system trusts it completely — because keyboards don't need driver approvals or admin permissions. Once trusted, it starts "typing" pre-programmed commands at superhuman speed. We're talking 1000 keystrokes per second. By the time you blink, it's already opened PowerShell, run a script, and closed the window. The original Hak5 Rubber Ducky costs around $80. I built mine for ₹150. What I Used DigiSpark ATtiny85 — ₹120–150 on Amazon India Arduino IDE — free A Windows test machine (my own laptop) 15 minutes That's it. No soldering. No special skills. Just a tiny microcontroller the size of a thumb. Setting It Up Step 1 — Install Arduino IDE Download from arduino.cc and install normally. Step 2 — Add DigiSpark Board Support Go to File → Preferences and paste this into Additional Board Manager URLs: http://digistump.com/package_digistump_index.json Then go to Tools → Board → Board Manager, search Digistump and install. Step 3 — Install Drivers DigiSpark needs Micronucleus drivers on Windows. Download from the official Digistump GitHub and run the installer. Step 4 — Write Your First Payload This opens Notepad and types a message — my first ever "attack": cpp#include "DigiKeyboard.h" void setup() { DigiKeyboard.delay(2000); DigiKeyboard.sendKeyStroke(KEY_R, MOD_GUI_LEFT); // Win+R DigiKeyboard.delay(500); DigiKeyboard.print("notepad"); DigiKeyboard.sendKeyStroke(KEY_ENTER); DigiKeyboard.delay(1000); DigiKeyboard.print("Hello. Your keyboard is now mine."); } void loop() {} Upload it, plug in the DigiSpark, and watch it type on its own. That moment hits different when y
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GuardDuo — The AI Guardian That Keeps Vibe-Coding in Check
AI coding tools are incredible. But I noticed something — they ship code fast, skip the rules, and nobody catches it until it's already in production. That's exactly what GuardDuo is built to fix. The Problem We're in the age of vibe-coding. You describe what you want, the AI builds it, it works — and you ship it. But "works" and "correct" are two very different things. Imagine asking an AI to build a login form. It works perfectly. But under the hood it has hardcoded API keys, no input validation, missing aria-labels , and it's using fetch directly instead of your project's apiClient wrapper. Your Issue said none of that was allowed. Nobody caught it. That's the vibe-coding trap — and it's happening on every team using AI-assisted development right now. What is GuardDuo GuardDuo is a GitLab Duo Agent skill that acts as your AI guardian. Instead of just reviewing code in isolation, it cross-references your code changes against the actual intent of the linked GitLab Issue — using the Orbit Knowledge Graph , which is essentially the brain that knows your project's rules, requirements, and success criteria. In plain terms: GuardDuo reads what the Issue asked for , reads what the code actually does , and tells you exactly where they don't match. It audits across three dimensions: 🔐 Security — hardcoded secrets, SQL injection, missing input validation ♿ Accessibility — missing alt text, aria-labels , poor color contrast 📐 Standards — deviations from your project's established patterns and conventions And when it finds a problem, it doesn't just flag it — it fixes it. How It Works Just open GitLab Duo Chat or GitLab Agent Platform(on your choice of IDE) -> choose the agent as GuardDuo and type: Audit issue #[issue no.] — GuardDuo pulls the Issue context from Orbit, analyzes the code, and returns a structured report Fix issue #[issue no.] — GuardDuo generates a corrected implementation that satisfies all requirements Or paste any code snippet directly and ask it to audit o
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Dependabot can finally pull from private GitHub Packages without a PAT
The first time I wired Dependabot up to a private package registry, it took three meetings and a calendar reminder set six months ahead. The reminder was for the personal access token I had to mint to do it, the one I would have to rotate by hand before it expired, living in a config that drifted somewhere between repo settings, a .github file, and an internal wiki page nobody had touched in a year. On June 23 GitHub posted a small changelog item that quietly retires that whole ritual: Dependabot can now read your private GitHub Packages and GHCR registries through its own GITHUB_TOKEN , no PAT required. If you have ever had to explain to a security review why your bot account holds a token your team owns but a person minted, you already know why this lands. The PAT we all had and nobody loved Until this week, Dependabot's path to a private GitHub-hosted package was the same path it took years ago. A human minted a personal access token, scoped wide enough to read the registry, stored it as a repo or org secret, and plugged it into Dependabot so the bot could authenticate when it tried to resolve dependencies. That token expired on a human schedule. It belonged to whoever happened to set Dependabot up, which is rarely the person who still owns the repo a year later. You can feel how that ends. Tokens that quietly expire and break a Dependabot PR the day someone needs the patch. Tokens that follow an offboarded engineer out the door. Tokens with scopes wider than the job actually requires, because nobody wanted to mint a fine-grained one per registry path. None of those failures are catastrophic on their own. All of them are the kind of papercut a platform team ends up owning. What the GITHUB_TOKEN does here The new behavior is straightforward. Dependabot's job-scoped GITHUB_TOKEN can now request a packages: read permission. When the bot pulls from a hostname under *.pkg.github.com or ghcr.io , it sends that token instead of asking for a PAT. The same token that alre
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Homebrew 6.0.0 turns third-party taps into an opt-in trust list
Your CI runner is a stranger with a credit card and root. Every brew install against a third-party tap is the same trust gesture as curl | sh , just wearing a nicer shirt. (We have all written that step in a script and clicked merge.) This week Homebrew said the quiet part out loud and asked you to consent to it first. The 6.0.0 release shipped the week before DevOps.com's writeup with a tap-trust gate. Out of the box, only taps on a pre-approved list will install. Anything else gets a refusal until a human runs brew trust user/repo . Trust binds to the remote's fully-qualified URL, so the same tap mirrored to a different host is a fresh decision, not a transitive one. What the gate actually refuses Before 6.0.0, the package manager treated user/repo as a name and walked off to fetch the formula. After 6.0.0, an unrecognised remote URL is a refusal at resolve time. Project Leader Mike McQuaid framed it in the 6.0.0 introductory post: The Homebrew team is aware of the supply-side security issues with other package managers. We've taken various steps to mitigate these risks for our users. (He has a point. The last few years of supply-chain incidents were not theoretical.) Tap-trust is one of those steps. It does not inspect the contents of a tap, scan a formula, or pin a SHA. What it does is force a human, or a script, to make an explicit, auditable statement: this remote URL is one we accept. Where your pipeline will feel it DevOps.com flags the part that matters for this site's audience: CI/CD pipelines using Homebrew will need to add brew trust commands to their setup scripts. Quietly bump the Homebrew action on your runner image and the next build that touches a non-core tap will fail at the install step, well before any test runs. That is a feature, but only if you read the changelog. The migration itself is a one-liner per tap. The cost is owning a list. Every tap your pipeline depends on now has to be enumerated somewhere, reviewed when it changes, and version-
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CKA Exam study 2026 Scenario 1 - The etcd Endpoint Trap
The etcd Endpoint Trap A cluster migration just took your whole control plane offline. In the next few minutes you'll find out why, and fix it the way the CKA exam expects. This is a CKA Troubleshooting walkthrough. Every command below is real output from a live cluster, and you can reproduce the whole thing yourself (scripts at the end). The scenario A single-node kubeadm cluster was migrated to a new machine. The control plane won't come up. Your task: identify the broken component, find the root cause, fix the config, restart, and verify. Single-node kubeadm cluster, freshly migrated Control plane will not start Find the broken component Root-cause it, fix it, verify How the control plane actually starts The kubelet runs the control plane as static pods from /etc/kubernetes/manifests . The kube-apiserver cannot start unless it can reach etcd. Give it the wrong etcd address and the apiserver crashes, so the whole cluster looks dead. The kube-apiserver runs as a static pod : the kubelet reads its manifest from /etc/kubernetes/manifests/ and keeps it running. The apiserver cannot start unless it can reach etcd, so a wrong --etcd-servers endpoint takes the whole API down, and with it, everything you'd normally use to debug. Step 1 — Reproduce the symptom First, reproduce the symptom. kubectl get nodes is refused. A refused connection on the API port means the API server is down: a control-plane problem, not a workload problem. $ kubectl get nodes The connection to the server cka-scenario1-control-plane:6443 was refused - did you specify the right host or port? A refused connection on the API port is a control-plane problem, not a workload problem. Step 2 — Investigate from the node kubectl can't help us now, so drop to the node. The kubelet itself is active. But follow its log and you'll see it stuck in a loop, restarting the apiserver over and over. The kubelet is fine; the static pod it manages is the problem. $ systemctl is-active kubelet active $ journalctl -u ku
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uv 0.11.19 + CPython 3.15, Spring AI 2.0, and the RAG Poisoning Problem
This week's releases split neatly into two categories: useful incremental hardening (uv, GitLab, Copilot) and things that should change how you architect systems today (Spring CVEs, pg_durable, and a Cornell paper that quietly invalidates a lot of RAG assumptions). The Spring security cluster alone is enough to justify a dependency audit before the weekend. uv 0.11.19 adds CPython 3.15 beta support uv now always computes SHA256 checksums for remote distributions—previously this was situational—and adds PyEmscripten platform support per PEP 783, which formalizes Python packaging for browser and WASM targets. CPython 3.15.0b2 is available as a managed runtime, and a cross-platform installation edge case on Windows hosts has been resolved. The SHA256 change is the one worth noting for security posture. Making verification unconditional rather than optional closes a gap where distribution integrity could go unchecked depending on resolver path. The PyEmscripten addition matters if you're packaging Python for browser runtimes—previously you were working around the absence of a formal platform tag; now you're not. Verdict: Ship. Drop-in upgrade, no breaking changes. If you manage Python distributions or target WASM, update now. Everyone else should still update—supply-chain hardening by default is worth the two minutes. GitLab 19.0 adds group-level review instructions, secrets manager GitLab 19.0 ships two meaningful additions for teams: group-level custom review instructions for Duo code review, configured via .gitlab/duo/mr-review-instructions.yaml with cascading inheritance across projects, and a Secrets Manager that exits closed beta for Premium and Ultimate tiers. Group-level review instructions solve a real annoyance—if you've been maintaining per-project AI review configuration across a monorepo organization, you can now centralize that and let projects inherit or override. It's the kind of change that sounds minor until you've had to sync a guideline update across
科技前沿
Year of free HPE software a “step in the correct direction” in VMware rivalry
Partner tells Ars that HPE should be giving out more free VM Essentials licenses.
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Building and Scaling a Platform with Project-as-a-Service
When a platform started with total developer autonomy, teams felt overwhelmed and ended up solving the same problems in completely different ways. The company shifted to enablement over support, working together with teams intensively, and helping teams feel confident and capable, turning the right way into being the easiest way. By Ben Linders
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How I Built an AI Invoice Generator with Groq, AWS DynamoDB, and Vercel v0
I built InvoiceAI an AI powered invoice generator that lets you describe what you want to invoice in plain English and get a fully formatted invoice in seconds, complete with PDF download and a real payment link. Here's how I built it for the #H0Hackathon. The Problem Freelancers and small businesses waste time manually creating invoices. You know what you did, who you did it for, and how much it costs you shouldn't have to fill out a form to capture that. The Stack - Vercel v0 — scaffolded the entire UI in one prompt Next.js 16 — framework Groq (Llama 3.3 70B) — AI natural language to invoice fields AWS DynamoDB — stores every generated invoice Paystack — generates real payment links jsPDF — client-side PDF generation Vercel — deployment How It Works User types: "50 hours of mobile app development at $80/hr for TechLagos Ltd, 7.5% VAT" Groq parses the text and extracts structured invoice data Live preview updates instantly User downloads PDF — invoice is saved to DynamoDB automatically One click generates a real Paystack payment link to send to the client Building the UI with v0 I used Vercel v0 to scaffold the entire UI in one prompt. It generated a production-ready Next.js component with a split-panel layout form on the left, live invoice preview on the right. I just had to wire up the AI and database logic. Connecting AWS DynamoDB Using the AWS SDK v3, I connected DynamoDB directly from Next.js server actions. Every time a user downloads an invoice, it's saved to DynamoDB with the client details, line items, tax rate, and timestamp. This gives the app a real data foundation that scales from day one. await dynamo . send ( new PutCommand ({ TableName : ' invoices ' , Item : { invoiceId : data . invoiceNumber , clientName : data . clientName , clientEmail : data . clientEmail , items : data . items , createdAt : new Date (). toISOString (), }, })) The Result AI generates invoice from plain English in under 2 seconds Real PDF download (no print dialog) Real Paystack