Guillaume Gelin ramnes

Alice's MongoDB FAQ

Personal

Which operating system do you use for your servers?

I use Gentoo Linux, for a wide variety of reasons. Performance is a big one, with the least amount of RAM utilized on startup after a fresh install, startup times to all-services-responding of around four seconds, and broad support for operation in a cluster: distributed computing. By default it compiles packages from source, allowing the installed packages to be highly optimized for the physical hardware it is running on, however it also integrates binary package support and distributed compiling allowing one "master" host to orchestrate compilation across an entire cluster. This results in "from depclean" kernel compiliation times in the order of 40 seconds in my production cluster. I SSHFS mount the package directory from the master on the other hosts and simply install the binary packages it produces.

Hand-installing a new Gentoo build takes around ten minutes on a reasonably powered VM

Hacky syntax highlighting in `git diff`

Normally git diff would color additions green and deletions red. This is cool, but it would be even cooler if it adds syntax highlighting to those lines. This is a git pager that does so.

It parses the diff output and picks up the SHAs of files with additions and deletions. It uses [CodeRay][coderay] to highlight each file and then it extracts the lines that are shown in the diff. It then uses [term/ansicolor][color] to make a gradient from the CodeRay color and the diff color (red for deletion, green for addition) and uses it to replace the original.

I tried using rugged instead of shelling out to git show – it was faster overall, but it did incur a noticeable start up time.

Check out the image below for a demo.

PSQL

Magic words:

psql -U postgres

Some interesting flags (to see all, use -h or --help depending on your psql version):

-E: will describe the underlaying queries of the \ commands (cool for learning!)
-l: psql will list all databases and then exit (useful if the user you connect with doesn't has a default database, like at AWS RDS)

	#!/usr/bin/env python2.7
	# -- coding: utf-8 --
	# vim:ts=2:sw=2:expandtab

	import os
	import xcb
	from xcb.xproto import *
	from PIL import Image

	XCB_MAP_STATE_VIEWABLE = 2

	#!/usr/bin/env python3
	"""xev output data parser to get mouse polling rate.

	Usage:
	$ chmod a+x mouserate
	$ xev \| mouserate
	"""
	import sys
	import re

	#include "keymap_common.h"

	/*
	Shane's Planck Layout

	http://www.keyboard-layout-editor.com/#/layouts/015d9011102619d7695c86ffe57cf441
	*/
	const uint8_t PROGMEM keymaps[][MATRIX_ROWS][MATRIX_COLS] = {
	[0] = KEYMAP( /* Base */
	TAB, Q, W, E, R, T, Y, U, I, O, P, MINS,

	class Factory(object):
	model = object

	def __init__(self):
	self._objs = {}

	def create(self, name):
	self._objs[name] = type(name, self.model.__bases__, dict(self.model.__dict__))
	return self._objs[name]

	def random_elsewhere_function():
	raise AttributeError("oops")


	class Foo(object):

	@property
	def bar(self):
	random_elsewhere_function()
	return "bar"

	class ObjectList(list):
	"""A list that can call its objects methods/variables and returns their
	own returns in a list. Obviously, the list should contains only one type of
	objects.

	Example of use:
	>>> foo = ObjectList(["bar", "baZ"])
	>>> foo.islower()
	[True, False]
	>>> foo.append(42)