Ahmed Clivern

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.

Revert the full commit

Sometimes you may want to undo a whole commit with all changes. Instead of going through all the changes manually, you can simply tell git to revert a commit, which does not even have to be the last one. Reverting a commit means to create a new commit that undoes all changes that were made in the bad commit. Just like above, the bad commit remains there, but it no longer affects the the current master and any future commits on top of it.

git revert {commit_id}

About History Rewriting

Delete the last commit

Deleting the last commit is the easiest case. Let's say we have a remote origin with branch master that currently points to commit dd61ab32. We want to remove the top commit. Translated to git terminology, we want to force the master branch of the origin remote repository to the parent of dd61ab32:

Processing JSON using jq

jq is useful to slice, filter, map and transform structured json data.

Installing jq

On Mac OS

brew install jq

Ruby on Rails Cheatsheet

Architecture

Create a new application

Install the Rails gem if you haven't done so before

EMOJI CHEAT SHEET

Emoji emoticons listed on this page are supported on Campfire, GitHub, Basecamp, Redbooth, Trac, Flowdock, Sprint.ly, Kandan, Textbox.io, Kippt, Redmine, JabbR, Trello, Hall, plug.dj, Qiita, Zendesk, Ruby China, Grove, Idobata, NodeBB Forums, Slack, Streamup, OrganisedMinds, Hackpad, Cryptbin, Kato, Reportedly, Cheerful Ghost, IRCCloud, Dashcube, MyVideoGameList, Subrosa, Sococo, Quip, And Bang, Bonusly, Discourse, Ello, and Twemoji Awesome. However some of the emoji codes are not super easy to remember, so here is a little cheat sheet. ✈ Got flash enabled? Click the emoji code and it will be copied to your clipboard.

People

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NOTE: This is a question I found on StackOverflow which I’ve archived here, because the answer is so effing phenomenal.

Q: How can I make a chain of function decorators in Python?

If you are not into long explanations, see [Paolo Bergantino’s answer][2].

	#!/usr/bin/env bash
	set -e

	echo "Installing dependencies..."
	sudo apt-get update -y
	sudo apt-get install -y unzip


	echo "Fetching vault..."
	VAULT=0.6.5

	# Copyright 2017, Google, Inc.
	# Licensed under the Apache License, Version 2.0 (the "License")
	FROM node:6-onbuild
	EXPOSE 3000
	ENV LANGUAGE English
	ENV API_KEY 123-456-789

	sudo apt-get install netcat openssl libpcre3 dnsmasq procps perl

	# for ubuntu 16.04 (xenial)

	sudo apt-get -y install postgresql postgresql-contrib phppgadmin
	sudo -i -u postgres

	psql
	CREATE USER kong; CREATE DATABASE kong OWNER kong;
	ALTER USER kong WITH password 'kong';

	// Now available in package form at https://github.com/rjz/githubhook

	package handler

	// https://developer.github.com/webhooks/
	import (
	"crypto/hmac"
	"crypto/sha1"
	"encoding/hex"
	"errors"