标签：#acti

Transaction lifecycle trong Postgres: BEGIN mở state machine, COMMIT đóng — quên đóng là dò mìn Một transaction trong Postgres không phải chỉ là cặp BEGIN ... COMMIT cú pháp; nó là một state machine sống cùng connection. BEGIN đẩy connection từ idle sang active , mỗi statement kết thúc đẩy nó về idle in transaction đợi statement kế tiếp, một statement lỗi đẩy sang idle in transaction (aborted) , và chỉ COMMIT / ROLLBACK mới trả connection về idle . Dev gặp lifecycle này trong việc thật không phải vì cú pháp khó mà vì một BEGIN quên COMMIT trong một code path lỗi: connection nằm trong pool ở idle in transaction vô thời hạn, giữ snapshot và lock, chặn autovacuum , kéo lock chain, làm bảng update-nóng bloat dần rồi cả service chậm chết. Cơ chế hoạt động Mặc định mỗi connection ở autocommit mode : mỗi statement là một transaction tự đóng. BEGIN (hoặc START TRANSACTION ) tắt autocommit cho tới khi gặp COMMIT / ROLLBACK . Trong khoảng đó connection có một xid (cấp khi cần ghi) và một snapshot, và lifecycle của nó đi qua các trạng thái mà Postgres phơi ra trong pg_stat_activity.state : idle — connection mở, không có transaction nào đang chạy. active — đang thực thi một statement (kể cả ngoài transaction block). idle in transaction — đang trong transaction block, vừa chạy xong một statement, đợi statement kế tiếp hoặc COMMIT / ROLLBACK . idle in transaction (aborted) — đang trong transaction, một statement đã ném lỗi, mọi statement tiếp theo trả ERROR: current transaction is aborted, commands ignored until end of transaction block cho tới khi ROLLBACK . fastpath function call / disabled — ít gặp, không phải mục tiêu của bài này. -- t0: state = 'idle' BEGIN ; -- t1: state = 'idle in transaction' (vừa thực thi xong BEGIN, đợi statement kế) INSERT INTO orders ( user_id , total ) VALUES ( 42 , 100 ); -- trong lúc chạy: state = 'active' -- sau khi statement xong: state = 'idle in transaction' lại INSERT INTO orders ( user_id , total ) VALUES ( NULL , 100 ); -- ERROR: null value

Read Committed: snapshot mỗi statement, và vì sao hai SELECT trong cùng transaction có thể trả khác nhau READ COMMITTED là isolation level mặc định của PostgreSQL, và là level mà phần lớn workload OLTP đang chạy mà không biết. Khác với mô hình "transaction lấy một snapshot rồi giữ nguyên" mà nhiều dev tưởng tượng từ MVCC, ở Read Committed mỗi statement lấy một snapshot mới tại thời điểm statement bắt đầu , không phải tại thời điểm BEGIN . Hậu quả thực tế: hai SELECT liên tiếp trong cùng một transaction có thể trả về dữ liệu khác nhau nếu giữa hai lần đó có transaction khác commit. Đây là non-repeatable read — đúng spec của Read Committed, không phải bug — và là nguồn của một class lỗi rất hay gặp: code đọc một giá trị, ra quyết định, rồi cập nhật dựa trên giá trị đã đọc, trong khi giá trị thực tế đã thay đổi. Cơ chế hoạt động Một transaction ở Read Committed không có transaction-level snapshot . Khi mỗi statement (mỗi SELECT , UPDATE , DELETE , INSERT ... SELECT ...) bắt đầu thực thi, backend lấy một snapshot mới gồm xmin , xmax và xip list — chính cái snapshot quyết định row version nào "visible" theo MVCC. Statement chỉ thấy: row có xmin đã commit trước thời điểm statement bắt đầu , và xmax chưa tồn tại hoặc thuộc một transaction chưa commit / đã abort. Ngay sau khi statement kết thúc, snapshot đó bị bỏ. Statement kế tiếp lấy snapshot mới — nếu trong khoảng giữa có transaction khác commit, statement này sẽ thấy dữ liệu mới đó. -- T1 BEGIN ; -- KHÔNG lấy snapshot ở đây SELECT balance FROM accounts WHERE id = 1 ; -- snapshot S1 -> trả 1000 -- ... T2 chạy: UPDATE accounts SET balance=500 WHERE id=1; COMMIT; SELECT balance FROM accounts WHERE id = 1 ; -- snapshot S2 -> trả 500 COMMIT ; Với UPDATE / DELETE / SELECT ... FOR UPDATE / FOR NO KEY UPDATE / FOR SHARE , Read Committed làm thêm một bước đặc biệt mà SELECT thường không làm: nếu target row bị một transaction khác đang lock (chưa commit), statement đợi transaction đó kết thúc. Khi unblock: nếu transaction kia ROL

Imagine you are planning a surprise birthday party. You need invitations, food, decorations, and a cake. You call different places to get these things. You tell each one exactly what you need. "I need 20 red balloons." "I need a chocolate cake for 10 people." This is how many computer programs talk to each other. They use something called an API (Application Programming Interface). An API is like a menu. You pick what you want. You get exactly that. It works well for simple tasks. But what if your party plans change? What if you decide on a theme mid-conversation? Traditional APIs can feel a bit rigid then. They don't always remember your past requests. They don't understand the bigger picture. Now, imagine talking to a super-smart party planner. You start by saying, "I'm planning a party." The planner asks, "For how many people?" You say, "About 20." Then you mention, "It's for a birthday." The planner instantly suggests a cake size. It recommends decorations based on your earlier answers. This smart planner remembers everything you said. It understands your overall goal. It uses something like MCP (Model Context Protocol). MCP is a new way for computers to talk. It's like having a real conversation. It's much smarter than a simple menu order. You will soon understand why this difference is a game-changer. Traditional APIs: The Fixed Menu Approach Let's start with what you might already know. Many apps you use every day rely on APIs. An API is like a waiter in a restaurant. You look at the menu. You tell the waiter your exact order. "I want a cheeseburger with fries." The waiter takes your order to the kitchen. The kitchen prepares only that specific meal. Then the waiter brings it back to you. This is how most apps work together. One app sends a very specific request. It asks for a certain piece of information or to perform a specific action. The other app performs that task. It sends back a very specific response. Think of ordering from an online store. You click

Tilt a CD or DVD under a desk lamp and a band of color sweeps across its surface. The disc is not painted; it is a spiral of microscopic pits, packed so tightly that they act on light the way a finely ruled scientific instrument does. Each wavelength of white light leaves the surface at its own angle, and your eye sees the result fanned out as a rainbow. That is a diffraction grating at work. The same principle that decorates a CD is the engine inside spectrometers that identify chemical elements, tune lasers, and read the composition of distant stars. This article explains how a grating spreads light, how to compute the angles, and where the analysis goes wrong. Why this calculation matters A prism also splits white light, but a grating does it with far more control and far more precision. Because the spreading depends on a countable number — the spacing between lines — a grating can be designed to send a chosen wavelength to a chosen angle. That predictability is what makes it the heart of the spectrometer. Spectroscopy underpins a remarkable range of work. Astronomers read a star's chemistry and velocity from the dark lines in its spectrum. Chemists identify unknown compounds by the wavelengths they absorb. Telecommunications engineers use gratings to combine and separate the many wavelengths sharing a single optical fiber. In every case the first task is the same: given the grating and the light, predict the angle at which each wavelength emerges. Get that wrong and a spectral line lands on the wrong detector pixel, and the measurement is meaningless. The core formula A diffraction grating is a surface ruled with a large number of equally spaced, parallel lines. When light passes through or reflects off it, each line acts as a source of secondary waves. Those waves interfere, and they reinforce each other only in specific directions — the directions where waves from neighboring lines arrive exactly in step. The condition for that reinforcement is the grating equ

A while back I wrote about 64% of our merged PRs being written by AI . A few people (reasonably) asked: "nice story, but can I verify any of that?" So we put it on a public, auto-updating dashboard: 👉 www.codens.ai/stats/en It shows, for our GitHub organization: What % of merged PRs are authored by AI agents (currently 65%) Median time from PR-open to merge (2 minutes) Who merged what — task-execution agents vs maintenance bots vs auto-fix vs humans Weekly AI-merge counts and a per-repository breakdown Every number is tallied straight from the GitHub API by a small collector script, and the page regenerates itself weekly. We can't inflate it — it's measured, and the down weeks show up too (that's kind of the point). Why bother making it public Two reasons. 1. "Trust me bro" doesn't scale. When you claim most of your code is AI-written, the only honest move is to expose the raw counts so anyone can sanity-check them. The dashboard is that receipt. 2. It's a live dogfooding test. The whole thing — the PRD, the implementation, the review, the auto-fix on production errors — runs on Codens , our own AI dev-automation suite. If our own numbers ever tanked, the dashboard would be the first place it'd show. Public accountability is a good forcing function. Funny footnote: the dashboard itself was code-reviewed by our own AI reviewer before it shipped, and it caught two real bugs — an OG-image percentage that had drifted out of sync with the live number, and a broken error-fallback that would have blanked the page on malformed data. The tool built to sell "AI reviews your PRs" reviewed the PR that announces it. We'll take it. If you want to see the same machinery on your repos, there's a 14-day free trial (no card): codens.ai . Japanese version of the dashboard is here .

Infrastructure as Code (IaC) has revolutionized how we provision and manage cloud resources. Tools like Terraform, Pulumi, and OpenTofu allow us to define infrastructure using code, making it versionable, repeatable, and scalable. However, with great power comes great responsibility. Misconfigurations in IaC can lead to massive security breaches, such as publicly exposed data storage or overly permissive access roles. This is where Static Application Security Testing (SAST) comes in. SAST tools analyze your source code to find security vulnerabilities before the code is deployed. In this article, we'll explore how to apply SAST to a Terraform project using Checkov , a popular open-source static analysis tool for IaC, and how to automate this process using GitHub Actions. (Note: We are intentionally avoiding tfsec for this demonstration to explore other powerful alternatives). Why Checkov? Checkov, created by Bridgecrew (now part of Prisma Cloud), is a static code analysis tool for IaC. It scans cloud infrastructure provisioned using Terraform, Terraform plan, Cloudformation, Kubernetes, Dockerfile, Serverless, or ARM Templates and detects security and compliance misconfigurations. It includes hundreds of built-in policies covering security and compliance best practices for AWS, Azure, and Google Cloud. The Demo Scenario: A Vulnerable S3 Bucket Let's start by creating a simple Terraform configuration for an AWS S3 bucket. We will intentionally introduce a security misconfiguration: making the bucket public without encryption. Create a file named main.tf : # main.tf provider "aws" { region = "us-east-1" } resource "aws_s3_bucket" "my_vulnerable_bucket" { bucket = "my-company-public-data-bucket-12345" } # Misconfiguration 1: Public Read Access resource "aws_s3_bucket_acl" "example" { bucket = aws_s3_bucket . my_vulnerable_bucket . id acl = "public-read" } If we were to deploy this, anyone on the internet could read the contents of this bucket. Let's see how Checkov can

In modern software development, Continuous Integration and Continuous Deployment (CI/CD) pipelines...

Disturbances in this critical sense are often linked to problems with brain health.

GitHub said this week that Copilot CLI, when it runs inside a GitHub Actions workflow, will accept the built-in GITHUB_TOKEN for authentication. Per the July 2 changelog, the previous path required creating and storing a personal access token. The operational read is small and precise: one fewer human-owned credential to mint, rotate and inherit. The exact scope of the change The changelog covers a narrow surface. It applies to Copilot CLI when invoked from a GitHub Actions workflow, and it swaps the required credential from a PAT to the workflow's ambient GITHUB_TOKEN . GitHub does not describe changes to how Copilot CLI authenticates outside Actions, and this post will not extrapolate to those contexts. If your Copilot CLI usage lives on a developer laptop or in another CI system, nothing in this announcement moves for you. Why the PAT was the wrong credential to leave in the loop A personal access token has almost none of the properties you would want from an automation credential. It does not expire on a job boundary. It carries a person's identity, not the workflow's. It sits in Actions secrets long enough to outlive the engineer who created it. And its scopes were chosen by that engineer, at that moment, often wider than the job actually needs. GITHUB_TOKEN is the opposite shape. Actions mints it at the start of a job, scopes it through the workflow's permissions: block, and revokes it when the job ends. If the token leaks, the window for abuse is the runtime of the job, not the years until somebody remembers to rotate it. When the person who wrote the workflow leaves, the pipeline does not silently break because a token expired with their account. For scripted Copilot CLI calls that had to be wrapped in a PAT, that is the whole win. The tool authenticates against the workflow instead of against a human. Wiring it up The workflow-side pattern is the same one every GITHUB_TOKEN -consuming step already follows: declare permissions: explicitly at the job level, k

Book: The Complete Guide to Go Programming Also by me: Hexagonal Architecture in Go — the companion book in the Thinking in Go series My project: Hermes IDE | GitHub — an IDE for developers who ship with Claude Code and other AI coding tools Me: xgabriel.com | GitHub You open a pull request in a Go repo you just joined. Ten minutes later there are six comments on it. None of them are about your logic. They point at a capitalized error string, a receiver named this , a context stored on a struct. Each comment links the same page: the Go Code Review Comments wiki. That page is the closest thing Go has to an official style council. It grew out of the comments Go's own maintainers left on CLs for years, and most Go teams treat it as the default rulebook. The problem is that the wiki tells you what but rarely why , so the rules read like arbitrary taste. They aren't. Each one exists because the alternative bit somebody. Here are ten that reviewers cite the most, with the reason behind each. Everything below is idiomatic on Go 1.23+. 1. Error strings are lowercase and unpunctuated The rule: an error string should not be capitalized and should not end with punctuation. // wrong return fmt . Errorf ( "Failed to open config." ) // right return fmt . Errorf ( "failed to open config" ) The reason is wrapping. Go errors get concatenated. Your string is almost never the whole sentence a user reads; it's a fragment in a chain built with %w : return fmt . Errorf ( "load settings: %w" , err ) // -> "load settings: open config: permission denied" Capitalize your fragment and you get load settings: Open config: permission denied in the middle of a line. End it with a period and you get a period in the middle of a longer message. Lowercase, no trailing punctuation, and every fragment composes cleanly no matter where it lands in the chain. The exception is a string that begins with an exported name or acronym, which keeps its own case ( HTTP , TLS ). 2. Receiver types are consistent ac

Book: The Complete Guide to Go Programming Also by me: Hexagonal Architecture in Go — the companion book in the Thinking in Go series My project: Hermes IDE | GitHub — an IDE for developers who ship with Claude Code and other AI coding tools Me: xgabriel.com | GitHub You write a Go struct with a private field and a method to read it. Muscle memory from Java, C#, or PHP takes over, and you type GetName() . The code compiles. Tests pass. Then a reviewer leaves a comment that just says "drop the Get" with no explanation, and you're left wondering whether that's a real rule or one person's taste. It's a real rule. It's written into the language's own style guide, the standard library follows it everywhere, and several linters will flag the code that breaks it. Go naming isn't a matter of opinion the way it is in some languages. A handful of conventions are baked into the tooling, and once you know them, half the reviewer nitpicks disappear. Getters drop the Get The convention comes straight from the Effective Go document. If you have an unexported field owner , the accessor is named Owner , not GetName or GetOwner . The mutator, if you need one, keeps the Set prefix. type File struct { owner string } func ( f * File ) Owner () string { return f . owner } func ( f * File ) SetOwner ( o string ) { f . owner = o } The reasoning is about how the call reads. person.Name() says the same thing as GetName() with less noise, and the parentheses already tell you it's a method call. Get adds a word that carries no information in a language where field access and method calls look different anyway. The Set prefix stays because there's no other clean way to signal mutation. Name() reads, SetName(x) writes. The asymmetry is deliberate. This shows up all over the standard library. bytes.Buffer has Len() , not GetLen() . sync.Once has no getters to get wrong, but http.Request exposes fields and methods that never carry a Get . time.Time has Hour() , Minute() , Second() . The pattern is

Last time I wrote about using glasp, a Go-based, npm-free CLI for Google Apps Script (GAS), in GitHub Actions. Previous post: Lean, Fast, Simple — npm-free GAS Deployment on GitHub Actions with glasp This time, a quick rundown of what landed in v0.3.0 and v0.4.0 . v0.3.0: PKCE support glasp login now supports PKCE (RFC 7636) as an opt-in. glasp login --pkce # or GLASP_USE_PKCE = 1 glasp login Each login generates a code_verifier and sends an S256 code_challenge to Google. It's a defense against authorization code interception, and it coexists fine with the existing client_secret flow. It only applies to the interactive login — --auth / GLASP_AUTH for CI is untouched. Off by default. Worth turning on if you're in a stricter security environment. v0.4.0: Timeouts and retries The focus here is basically "can this run unattended in CI/CD without falling over." Timeouts Script API requests previously had no timeout — a stuck request could hang the job indefinitely. v0.4.0 adds a 180s default. glasp push --timeout 60 # set to 60s glasp push --no-timeout # disable Also configurable via GLASP_TIMEOUT / GLASP_NO_TIMEOUT env vars or timeoutSeconds in .glasp/config.json . Priority: --no-timeout > flag/env > config > default. If the config file is broken, it warns instead of silently falling back. Retries Transient failures (5xx, 429) now get retried automatically. glasp push --max-retries 5 glasp push --no-retries 3 retries by default (up to 4 attempts total) Only applies to idempotent commands: push , pull , clone , list-deployments Commands with side effects ( create-script , run-function , etc.) are never retried Exponential backoff with jitter, respecting Retry-After It's implemented as a single http.RoundTripper wrapper, so the Google SDK itself isn't touched — same pattern as the timeout implementation. retryTransport → oauth2.Transport → http.DefaultTransport Some refactoring, too Internal packages got reorganized ( #107 ), and the hand-rolled retry transport was swappe

Acti is betting the smartphone keyboard is the next home for AI assistants. The startup's new keyboard for iOS and Android works across apps and lets users create custom AI-powered shortcuts using natural language.

This article covers the MCP setup and configuration for using Google Nano Banana 2 Lite and...

trpc has a scheduled workflow called "Lock Issues & PRs." Its own scorecard shows it failing on almost every run. It is still scheduled, still running, still red. trpc ships excellent software, which is exactly the point: if a project this careful has a workflow that has been red for ages, the rest of us almost certainly do too. It is not a one-off. drizzle-orm has one ("Unpublish release"). cal.com has one ("PR Update"). I scanned 35 popular open-source repos and the same thing kept turning up: a scheduled workflow that fails on nearly every run, quietly, for a long time. Why nobody notices GitHub does email you when a scheduled workflow fails. So how do these survive? Two reasons. First, those emails are routine. You get them for flaky reruns and transient blips too, so you filter them out. Second, a workflow that is always red stops reading as a signal. It is just how that row looks now. I did exactly this on my own project. GitHub emailed me that a workflow had failed. The next day it emailed again. I saw it, told myself I would fix it tomorrow, and promptly forgot. It was my nightly database backup, quietly broken the whole time, and I only caught it when a failure-rate number crept up where I would notice. An always-red workflow is not free It burns minutes every run to produce nothing but a red X. Worse, it trains you to ignore the failure that actually matters: the day a real one lands in the same inbox you have learned to skim past. How to find yours Open your Actions tab and look at the scheduled workflows, the cron-triggered ones nobody watches. If the last several runs are all red, you found one. From the CLI: gh run list --workflow = "Lock Issues & PRs" --status = failure What to do about it Two honest options: fix it, or if the workflow is genuinely abandoned, turn it off. Do not leave it scheduled and red. gh workflow disable "Lock Issues & PRs" Or drop the schedule trigger from the workflow file if it should not run on a timer at all. A disabled work

Two days ago GitHub emailed me to say one of my workflows had failed. The next day it emailed me again. I saw it, told myself I would fix it tomorrow, and promptly forgot. It was my nightly database backup, quietly broken the whole time, and I only caught it because a failure-rate number nudged up. A failed run at least gets you an email. A slow run gets you nothing. GitHub never pings you when CI quietly takes twice as long, runs the whole suite twice per PR, or rebuilds dependencies from scratch every time. That waste compounds where no one looks. Here are the usual culprits, each with the exact fix. When I scanned 35 popular open-source repos, not one had a fully clean config. 32 of 35 had no concurrency control, 33 of 35 had no job timeouts, and 22 of 35 ran the full suite twice on every PR. If projects this polished leave minutes on the table, the rest of us definitely do. Your suite runs twice on every PR Trigger a workflow on both push and pull_request and, for a branch in the same repo, opening a PR fires both. You just paid for two identical runs. This one is pure waste and it can roughly halve your PR-related minutes. Trigger on pull_request , and keep push for your default branch: on : push : branches : [ main ] pull_request : Old runs don't cancel when you push again Push a fix 30 seconds after the first push and, with no concurrency group, both runs go to completion. The first is dead weight, and it is holding a slot in your queue while it finishes. This hides even when you do have a group: astro has a concurrency group on one workflow but left off cancel-in-progress , which our scan estimates leaves roughly 1,850 minutes a month on the table. Add a group keyed on the branch, with cancel-in-progress , so a new push supersedes the old run: concurrency : group : ${{ github.workflow }}-${{ github.ref }} cancel-in-progress : true Every run reinstalls dependencies from scratch No cache means every run re-downloads and rebuilds your dependencies. On a typical

Introduction In the world of distributed systems, complexity is the beast we’re all trying to tame. Teams building platforms often fall into the trap of believing that hiding this complexity is the ultimate goal. The logic seems sound: if users don’t see the mess, they won’t be burdened by it. But this approach, while well-intentioned, often leads to the creation of illusions —systems that appear simple on the surface but are brittle and unpredictable beneath. These illusions don’t just fail to solve the problem; they exacerbate it, leading to increased cognitive load, unexpected failures, and long-term maintenance nightmares. Consider a platform designed to abstract away the intricacies of distributed transactions. If the abstraction merely masks the complexity without addressing its root causes—such as inconsistent network latencies or partial failures—users will eventually encounter edge cases where the system behaves unpredictably. For example, a transaction might appear to succeed but fail silently due to a race condition in the underlying distributed lock mechanism. The illusion of simplicity breaks down when the system’s internal state deforms under pressure, leading to data inconsistencies or service outages. The core issue lies in the misunderstanding of abstractions . A meaningful abstraction doesn’t just hide complexity; it transforms it into a more manageable form. It exposes the essential properties of the system while encapsulating the non-essential details. In contrast, an illusion merely obscures the complexity, leaving it to fester beneath the surface. For instance, an abstraction might provide a consistent API for distributed state management, while internally handling retries, idempotency, and conflict resolution. An illusion, on the other hand, might simply wrap a flaky distributed database in a prettier interface, without addressing the underlying issues of consistency or availability. The pressure to deliver platforms quickly often exacerbates

Clicking on the links now reveals blank pages and empty PDFs. "Intellectually, it’s not acceptable.”

In the previous article on hosting a Next.js app on a VPS , I'd left the deployment pipeline as a rough sketch: four lines to say "it ships to production on its own when you push." That's the piece I want to open up here, because it's what separates a VPS you fuss over by hand from infrastructure you can forget about. There's a stubborn myth that CI/CD is a big-company thing, with a dedicated DevOps team and six-figure tooling. Not true. The pipeline that deploys this portfolio fits in two YAML files, you can read it in five minutes, and it gives me back exactly the comfort I liked about Vercel: I push to master , I go grab a coffee, the app is live when I'm back. The one thing I gained along the way is knowing precisely what happens between the git push and the running container. Four steps, in this order Deployment is a chain. On every push to master , GitHub Actions runs lint, security scan, image build, and deploy. What matters is the needs : as long as a step fails, the following ones don't start. A critical vulnerability caught by the scan, and the image never gets built. At all. jobs : lint : # ESLint runs-on : ubuntu-latest # ... security : # Trivy scan (reusable workflow) uses : ./.github/workflows/security.yml build-push : # build the Docker image → push to GHCR needs : [ lint , security ] # ... deploy : # SSH to the VPS → docker compose pull && up -d needs : [ build-push ] # ... Lint first, because it's the cheapest step and there's no point building an image if ESLint is already screaming. The scan next, as a barrier. Then the build, which produces the Docker image and pushes it to GHCR, GitHub's container registry (private, in my case). And finally the deploy, which connects over SSH to the VPS, pulls the new image and restarts the container. Four links, each blocking the next. That's the whole secret. The security scan is in the path, not in a review "for later" This is the one I won't budge on. Dependency security, in a lot of projects, is a Dependabo

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