Vincent Marquet vmarquet

Finding a Ruby memory leak using a time analysis

When developing a program in Ruby, you may sometimes encounter a memory leak. For a while now, Ruby has a facility to gather information about what objects are laying around: ObjectSpace.

There are several approaches one can take to debug a leak. This discusses a time-based approach, where a full memory dump is generated every, say, 5 minutes, during a time that the memory leak is showing up. Afterwards, one can look at all the objects, and find out which ones are staying around, causing the

Keybase proof

I hereby claim:

I am hdm on github.
I am hdm (https://keybase.io/hdm) on keybase.
I have a public key whose fingerprint is 98EF 5533 E7EA FD56 9669 59B5 7549 FB3D B1DD 1F32

To claim this, I am signing this object:

📂 Persistent "pipes" in Linux

In a project I'm working on I ran into the requirement of having some sort of persistent FIFO buffer or pipe in Linux, i.e. something file-like that could accept writes from a process and persist it to disk until a second process reads (and acknowledges) it. The persistence should be both across process restarts as well as OS restarts.

AFAICT unfortunately in the Linux world such a primitive does not exist (named pipes/FIFOs do not persist

This guide assumes that you recently run brew upgrade postgresql and discovered to your dismay that you accidentally bumped from one major version to another: say 9.3.x to 9.4.x. Yes, that is a major version bump in PG land.

First let's check something.

brew info postgresql

The top of what gets printed as a result is the most important:

You got your hands on some data that was leaked from a social network and you want to help the poor people.

Luckily you know a government service to automatically block a list of credit cards.

The service is a little old school though and you have to upload a CSV file in the exact format. The upload fails if the CSV file contains invalid data.

The CSV files should have two columns, Name and Credit Card. Also, it must be named after the following pattern:

YYYYMMDD.csv.

	#!/usr/bin/env python

	import random
	import struct
	import sys

	# Most of the Fat32 class was cribbed from https://gist.github.com/jonte/4577833

	def ppNum(num):
	return "%s (%s)" % (hex(num), num)

	#!/usr/bin/sudo sh

	## ruby_revealer.sh -- decrypt obfuscated GHE .rb files. 2.0.0 to 2.3.1+.

	## From `strings ruby_concealer.so`:
	##
	## > This obfuscation is intended to discourage GitHub Enterprise customers
	## > from making modifications to the VM.
	##
	## Well, good, as long as its not intended to discourage me from doing this!

	#
	# read/write access to python's memory, using a custom bytearray.
	# some code taken from: http://tinyurl.com/q7duzxj
	#
	# tested on:
	# Python 2.7.10, ubuntu 32bit
	# Python 2.7.8, win32
	#
	# example of correct output:
	# inspecting int=0x41424344, at 0x0228f898

	# You don't need Fog in Ruby or some other library to upload to S3 -- shell works perfectly fine
	# This is how I upload my new Sol Trader builds (http://soltrader.net)
	# Based on a modified script from here: http://tmont.com/blargh/2014/1/uploading-to-s3-in-bash

	S3KEY="my aws key"
	S3SECRET="my aws secret" # pass these in

	function putS3
	{
	path=$1

	/* bling.js */
	window.$ = document.querySelector.bind(document);
	window.$$ = document.querySelectorAll.bind(document);
	Node.prototype.on = window.on = function(name, fn) { this.addEventListener(name, fn); };
	NodeList.prototype.__proto__ = Array.prototype;
	NodeList.prototype.on = function(name, fn) { this.forEach((elem) => elem.on(name, fn)); };