Steve Chavez steve-chavez

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.

What I Wish I'd Known About Equity Before Joining A Unicorn

Disclaimer: This piece is written anonymously. The names of a few particular companies are mentioned, but as common examples only.

This is a short write-up on things that I wish I'd known and considered before joining a private company (aka startup, aka unicorn in some cases). I'm not trying to make the case that you should never join a private company, but the power imbalance between founder and employee is extreme, and that potential candidates would

Nix String and Path Concatenation

From Bas van Dijk:

To understand these things I would recommend using nix-repl:

$ nix-repl
Welcome to Nix version 1.11.2. Type :? for help.

Using Python 3 + Google Cloud Vision API's OCR to extract text from photos and scanned documents

Just a quickie test in Python 3 (using Requests) to see if Google Cloud Vision can be used to effectively OCR a scanned data table and preserve its structure, in the way that products such as ABBYY FineReader can OCR an image and provide Excel-ready output.

The short answer: No. While Cloud Vision provides bounding polygon coordinates in its output, it doesn't provide it at the word or region level, which would be needed to then calculate the data delimiters.

On the other hand, the OCR quality is pretty good, if you just need to identify text anywhere in an image, without regards to its physical coordinates. I've included two examples:

####### 1. A low-resolution photo of road signs

There's no history in the database itself, if you're using psql you can use "\s" to see your command history there.

You can get future queries or other types of operations into the log files by setting log_statement in the postgresql.conf file. What you probably want instead is log_min_duration_statement, which if you set it to 0 will log all queries and their durations in the logs. That can be helpful once your apps goes live, if you set that to a higher value you'll only see the long running queries which can be helpful for optimization (you can run EXPLAIN ANALYZE on the queries you find there to figure out why they're slow).

Another handy thing to know in this area is that if you run psql and tell it "\timing", it will show how long every statement after that takes. So if you have a sql file that loo

	# Automatic nginx virtual subdomains with sub-folders or sub-directories
	#
	# Since the original source where I found this code is now offline, I have decided to mirror it here.
	# All credit goes to: http://web.archive.org/web/20150307193208/http://www.messaliberty.com/2010/10/automatic-nginx-virtual-subdomains-with-sub-folders-or-sub-directories
	#
	# Description: In my web root directory I wanted create a folder called photos, and another called
	# music using a sftp program. Without manually going back to the config file or to the shell I like to
	# be able to access them at photos.nginxdomain.com and music.nginxdomain.com. That is what this config does.

	# Redirect visitors from http://nginxdomain.com/ to http://www.nginxdomain.com/

	module Main where

	import Data.List ( sort, sortBy )
	import Data.Ord (comparing)
	import Data.Maybe
	import Control.Monad (msum)
	import System.IO
	import System.Random
	import Options.Applicative

	alias accio=wget
	alias avadaKedavra='rm -f'
	alias imperio=sudo
	alias priorIncantato='echo `history \|tail -n2 \|head -n1` \| sed "s/[0-9]* //"'
	alias stupefy='sleep 5'
	alias wingardiumLeviosa=mv

	alias sonorus='set -v'
	alias quietus='set +v'

	#include <errno.h>
	#include <inttypes.h>
	#include <stdio.h>
	#include <stdlib.h>
	#include <unistd.h>
	#include <string.h>
	#include <sys/epoll.h>
	#include <sys/timerfd.h>

	static char itimerspec_dump(struct itimerspec ts);

	/// This type is only every inhabited when S is nominally equivalent to T
	#[derive(Debug)]
	pub struct Is<S, T>(::std::marker::PhantomData<(const S, const T)>);

	// Construct a proof of the fact that a type is nominally equivalent
	// to itself.
	pub fn is<T>() -> Is<T, T> { Is(::std::marker::PhantomData) }

	// std::mem::transmute does not accept unsubstituted type parameters
	// manual transmute as suggested by manual