codesnips

redis

ruby 
require "securerandom"

class RedisMutex
  class LockError < StandardError; end

  UNLOCK_SCRIPT = <<~LUA.freeze

Redis-Based Distributed Mutex (with TTL)

rails redis concurrency
by codesnips 2 tabs
go 
package pricecache

import (
	"context"
	"sync"

Collapse Concurrent Identical Requests in Go with singleflight

go singleflight concurrency
by codesnips 3 tabs
ruby 
class PresenceRegistry
  TTL = 30 # seconds a user counts as present without a heartbeat

  def initialize(room_id, redis: REDIS)
    @room_id = room_id
    @redis = redis

Action Cable Presence Tracking (Lightweight)

rails actioncable redis
by codesnips 3 tabs
php 
<?php

namespace App\Jobs;

use App\Models\Invoice;
use App\Services\StripeGateway;

Preventing Double-Charges in Laravel with WithoutOverlapping Job Middleware

laravel queues background-jobs
by codesnips 3 tabs
php 
<?php

namespace App\Observers;

use App\Models\Product;
use App\Jobs\WarmRelatedProductsCache;

Warm a Related-Products Cache with a Queued Laravel Job on Inventory Change

laravel php caching
by codesnips 3 tabs
php 
<?php

declare(strict_types=1);

namespace App\Security;

PHP Login Rate Limiting with a Sliding-Window Throttle Middleware

php rate-limiting middleware
by codesnips 3 tabs
lua 
-- KEYS[1] = bucket key
-- ARGV[1] = capacity, ARGV[2] = refill_rate (tokens/sec)
-- ARGV[3] = now_ms, ARGV[4] = requested tokens
local capacity    = tonumber(ARGV[1])
local refill_rate = tonumber(ARGV[2])
local now_ms      = tonumber(ARGV[3])

Token Bucket Rate Limiting in a Servlet Filter with Redis and Lua

rate-limiting token-bucket servlet
by codesnips 3 tabs
ruby 
class SlidingWindowLimiter
  Result = Struct.new(:allowed, :count, :limit, :window_ms, keyword_init: true)

  SCRIPT = <<~LUA.freeze
    local key = KEYS[1]
    local now = tonumber(ARGV[1])

Rate Limiting with Redis + Increment Expiry

rails redis reliability
by codesnips 3 tabs
python 
import time
from collections import namedtuple

from sqlalchemy import text

CheckResult = namedtuple("CheckResult", ["name", "healthy", "latency_ms", "detail"])

Flask Health-Check Blueprint Reporting Database and Redis Status as JSON

flask health-check observability
by codesnips 3 tabs
ruby 
class DebouncedReindexJob
  include Sidekiq::Job

  sidekiq_options queue: :indexing, retry: 5

  DEBOUNCE_DELAY = 5 # seconds

Debouncing Sidekiq Jobs Per-Record With Redis So Rapid Updates Coalesce Into One Run

rails sidekiq redis
by codesnips 3 tabs
go 
package mailer

import (
	"crypto/sha256"
	"encoding/hex"
	"strings"

Idempotent Email Sending with a Redis Fingerprint Set in Go

redis idempotency email
by codesnips 3 tabs
go 
package health

import (
	"context"
	"sync"
	"time"

Concurrent Readiness Health Check Endpoint in Go with Timeouts

go health-check readiness
by codesnips 3 tabs