codesnips

concurrency

go 
package limiter

import (
	"context"
	"errors"
)

Leaky-Bucket Concurrency Limiter with a Buffered Semaphore Channel in Go

go concurrency rate-limiting
by codesnips 3 tabs
rust 
use std::collections::HashMap;
use std::sync::Mutex;

pub type AccountId = u64;
pub type Cents = i64;

Atomic Double-Entry Ledger Transfers With Rust Locking and Poison Recovery

ledger concurrency double-entry
by codesnips 3 tabs
typescript 
import { EventEmitter } from "events";

export interface Job<T> {
  id: string;
  payload: T;
  attempts: number;

Typed In-Memory Job Queue With a Concurrency-Limited Worker Pool

typescript job-queue concurrency
by codesnips 3 tabs
javascript 
'use strict';

function dedupeAsync(producer, keyFn) {
  const pending = new Map();
  const resolveKey = keyFn || ((...args) => JSON.stringify(args));

Deduplicate Concurrent Async Calls With a Promise Cache in Node.js

nodejs async promises
by codesnips 3 tabs
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