ptarjan

Scaling your API with rate limiters

The following are examples of the four types rate limiters discussed in the accompanying blog post. In the examples below I've used pseudocode-like Ruby, so if you're unfamiliar with Ruby you should be able to easily translate this approach to other languages. Complete examples in Ruby are also provided later in this gist.

In most cases you'll want all these examples to be classes, but I've used simple functions here to keep the code samples brief.

Request rate limiter

This uses a basic token bucket algorithm and relies on the fact that Redis scripts execute atomically. No other operations can run between fetching the count and writing the new count.

chsh

#
# A:
# pubsub = PgPubSub.new('channelname')
# pubsub.subscribe do |data|
#  puts "data: #{data} is coming!"
# end
#
# B:
# pubsub = PgPubSub.new('channelname')
# pubsub.publish("hello world")

equivalent

• Rails 7.0.2
• stimulus js
• importmaps
• dropzone.js
• direct upload ActiveStorage

This is simple implementation of technologies in hobby project of mine built in Rails7 where I need direct upload to S3.

erikh

#!/usr/bin/env sh

##
# This is script with usefull tips taken from:
#   https://github.com/mathiasbynens/dotfiles/blob/master/.osx
#
# install it:
#   curl -sL https://raw.github.com/gist/2108403/hack.sh | sh
#

rkumar

#!/usr/bin/env ruby -w
## Using ruby's standard OptionParser to get subcommand's in command line arguments
## Note you cannot do: opt.rb help command
## other options are commander, main, GLI, trollop...

# run it as
# ruby opt.rb --help
# ruby opt.rb foo --help
# ruby opt.rb foo -q
# etc

nonsintetic

/*
 * This sketch illustrates how to set a timer on an SAMD21 based board in Arduino (Feather M0, Arduino Zero should work)
 * It should generate a 1Hz square wave as it is (thanks richdrich for the suggestion)
 * Some more info about Timer Counter works can be found in this article: 
 * http://www.lucadavidian.com/2017/08/08/arduino-m0-pro-il-sistema-di-clock/
 * and in the datasheet: http://ww1.microchip.com/downloads/en/DeviceDoc/SAM_D21_DA1_Family_DataSheet_DS40001882F.pdf
*/

uint32_t sampleRate = 1000; //sample rate in milliseconds, determines how often TC5_Handler is called

stalniy

Прошивка Wemos D1 mini для ebusd адаптера

Зазначені нижче кроки будуть актуальні для linux (ubuntu) та macos, вінда на "відпочинку" не мав змоги перевірити це там. Для прошивки будемо використовувати esptool.py

Вимоги: ubuntu : встановлений пайтон 3.8.10, або вище (має бути доступний за замовчанням, перевіряємо: python3 -V) macos : встановлений brew, за допомогою якого доставимо все необхідне

Установка esptool: MacOS:

lazaronixon

import { Controller } from "stimulus"
import { DirectUpload } from "@rails/activestorage"
import Dropzone from "dropzone"
import { getMetaValue, findElement, removeElement, insertAfter } from "helpers"

Dropzone.autoDiscover = false

export default class extends Controller {
  static targets = [ "input" ]

isaacs

# Hello, and welcome to makefile basics.
#
# You will learn why `make` is so great, and why, despite its "weird" syntax,
# it is actually a highly expressive, efficient, and powerful way to build
# programs.
#
# Once you're done here, go to
# http://www.gnu.org/software/make/manual/make.html
# to learn SOOOO much more.

chanks

Turning PostgreSQL into a queue serving 10,000 jobs per second

RDBMS-based job queues have been criticized recently for being unable to handle heavy loads. And they deserve it, to some extent, because the queries used to safely lock a job have been pretty hairy. SELECT FOR UPDATE followed by an UPDATE works fine at first, but then you add more workers, and each is trying to SELECT FOR UPDATE the same row (and maybe throwing NOWAIT in there, then catching the errors and retrying), and things slow down.

On top of that, they have to actually update the row to mark it as locked, so the rest of your workers are sitting there waiting while one of them propagates its lock to disk (and the disks of however many servers you're replicating to). QueueClassic got some mileage out of the novel idea of randomly picking a row near the front of the queue to lock, but I can't still seem to get more than an an extra few hundred jobs per second out of it under heavy load.

So, many developers have started going straight t