codesnips

concurrency

ruby 
class LastSeenTracker
  THROTTLE = 5.minutes
  PENDING_KEY = "pending:last_seen".freeze

  class << self
    def touch(user_id, at: Time.current)

Database “Last Seen” without Hot Row Updates

rails performance redis
by codesnips 3 tabs
ruby 
class CreateReservations < ActiveRecord::Migration[7.1]
  def up
    enable_extension "btree_gist" unless extension_enabled?("btree_gist")

    create_table :reservations do |t|
      t.references :room, null: false, foreign_key: true

DB-Level “no overlapping ranges” with exclusion constraint

rails postgres exclusion-constraint
by codesnips 3 tabs
php 
<?php

use Illuminate\Database\Migrations\Migration;
use Illuminate\Database\Schema\Blueprint;
use Illuminate\Support\Facades\Schema;

Slugify Post Titles on Save With a Laravel Model Observer and Guaranteed Uniqueness

laravel eloquent observer
by codesnips 4 tabs
go 
package bank

import "errors"

var ErrVersionConflict = errors.New("optimistic lock: version conflict")
var ErrInsufficientFunds = errors.New("insufficient funds")

Optimistic Locking in Go With a Version Column on UPDATE

optimistic-locking concurrency postgres
by codesnips 3 tabs
python 
import queue
import time
from dataclasses import dataclass, field, replace
from typing import Any, Dict, Tuple

In-Process Threaded Background Job Queue for Sending Emails Without Redis

background-jobs threading queue
by codesnips 4 tabs
erb 
<%= form_with url: bulk_update_orders_path, method: :patch, data: { turbo_confirm: "Update selected orders?" } do %>
  <div class="batch-toolbar">
    <%= select_tag :status,
          options_for_select(Order.statuses.keys.map { |s| [s.humanize, s] }),
          prompt: "Set status to\u2026" %>
    <%= submit_tag "Apply to selected", class: "btn" %>

Bulk-Updating Order Statuses with a Checkbox Collection and update_all Batch Action in Rails

rails activerecord update-all
by codesnips 3 tabs
rust 
use std::time::Duration;

#[derive(Debug, Clone, PartialEq, Eq)]
pub struct Config {
    pub endpoint: String,
    pub timeout: Duration,

Lock-Free Config Reads With Arc-Swap and Copy-on-Write Snapshots in Rust

rust arc copy-on-write
by codesnips 3 tabs
go 
package ratelimit

import (
	"sync"
	"time"
)

Token Bucket Rate-Limiting Middleware for a Go net/http API

go net-http middleware
by codesnips 4 tabs
go 
package watch

import (
	"sync"
	"time"
)

Debounce Filesystem Change Events Before Triggering a Rebuild in Go

fsnotify debounce filewatcher
by codesnips 3 tabs
ruby 
module RequestStore
  def self.store
    Thread.current[:request_store] ||= {}
  end

  def self.fetch(key)

Hot Path Memoization (within request only)

rails performance memoization
by codesnips 4 tabs
rust 
use std::time::Duration;
use tokio_util::sync::CancellationToken;

pub struct Worker {
    id: usize,
    token: CancellationToken,

Graceful Task Shutdown in Tokio Using CancellationToken

tokio async cancellation
by codesnips 3 tabs
java 
@Configuration
@EnableAsync
public class AsyncConfig {

    @Bean(name = "orderExecutor")
    public ThreadPoolTaskExecutor orderExecutor() {

Debouncing Order Recalculations with Spring @Async and a Configured ThreadPoolTaskExecutor

spring-boot async thread-pool
by codesnips 3 tabs