Python - Matplotlib and Numpy on Debian/Ubuntu

There are `python-matplotlib` and `python-numpy` packages in the Debian/Ubuntu repos.

However, if you want to run in a virtualenv (with no-site-packages), and pip install these packages from PyPI, you need some system dependencies installed first to build with:

$ sudo apt-get install build-essential python-dev libfreetype6-dev libpng-dev python-virtualenv

Then, you can create a virtualenv, and the installers for Numpy and Matplotlib will work:

$ virtualenv env
$ cd env
$ source bin/activate
(env)$ pip install numpy matplotlib

...
...
Successfully installed numpy matplotlib
Cleaning up...

(tested on Ubuntu Oneiric 11.10 and Ubuntu Precise 12.04 alpha)

Officially Introducing "SST" (Python Web Test Framework)

"SST (selenium-simple-test) is a framework built on Selenium WebDriver, using Python to make writing functional web tests easier with code."

Since early 2011, I have been working for Canonical on the Infrastructure Systems Development team (Core Dev Ops).

[pic of canonical-isd-hackers at UDS-P-Orlando]

A by-product of our recent development efforts is a web testing framework. It has been available on Launchpad for a while, but I've never really announced it in public. We are using SST internally, and I want to expose it to a wider audience.

What is Selenium WebDriver?

Selenium (WebDriver) is a popular open-source library for automating browsers. It can be used to create functional/acceptance tests of a web application. The Selenium client bindings provide API's that allow you to programatically drive a browser and access web content/elements. The bindings are available and supported for many languages and platforms.

While working directly with Selenium API's from code is fine for ad-hoc browser interaction, it is rather low-level and lacks things necessary for creating suites of automated web tests. For larger-scale testing, you will soon want to use a framework to help organize, execute, and report.

Introducing SST...

SST aims to keep things simple.

Tests are made up of scripts, created by composing actions that drive a browser and assert conditions. You have the flexibility of the full Python language, along with a convenient set of functions to simplify web testing.

SST framework consists of:

• user actions and assertions (API) in Python
• test case loader (generates/compiles scripts to unittest cases)
• console test runner
• data parameterization/injection
• selectable output reports
• selectable browsers
• headless (xvfb) mode
• screenshots on errors

Test output can be displayed to the console, saved as an HTML report, or JUnit-compatible XML for compatibility with CI systems.

SST is free open source software (Apache Licensed). SST is primarily being developed on Linux, specifically Ubuntu. It should work fine on other platforms, but any issues (or even better - patches) should be reported on the Launchpad project:

• https://launchpad.net/selenium-simple-test

I just uploaded SST 0.1.0 to PyPI:

• http://pypi.python.org/pypi/sst

go ahead, give it a try:

• `$ [sudo] pip install sst`

documentation and more info:

• http://testutils.org/sst

a sample test script in SST:

from sst.actions import *

go_to('http://www.ubuntu.com/')
assert_title_contains('Ubuntu homepage')

Here is the development progress of SST (shown as a code_swarm visualization) over the past 8 months:

Special thanks to all the SST code committers so far:

• Danny Tamez
• Julien Funk
• Kenneth Koontz
• Leo Arias
• Lukasz Czyzykowkski
• Rick McBride
• Sidnei da Silva

Extra special thanks to SST's initial creator:

• Michael Foord

Happy New Year!

-Corey Goldberg

"Web Performance Testing night" in Boston/Cambridge - Python Meetup Dec. 19

I will be speaking at: "Web Performance Testing, lightning talks, and beers" at the Boston Python User Group.

Event Info: http://meetup.bostonpython.com/events/36664122/
Date: Monday, December 19, 2011, 7:00 PM
Location: Microsoft NERD, Cambridge, MA

"Corey Goldberg of Canonical and Dan Kuebrich of Tracelytics will tag-team to tell us about web performance testing, and a few interesting tools they've built."

Free pizza and beer!
Come Join!

---

Edit/Update:
Thanks to all who attended! The night was a big success.

The slides from my portion of the presentation are posted here:
webperf.html

Python - Stock Quotes From Google Finance

Quick example of retrieving stock quotes from Google Finance in Python:

#!/usr/bin/env python

import json
import pprint
import urllib2


def get_stock_quote(ticker_symbol):   
    url = 'http://finance.google.com/finance/info?q=%s' % ticker_symbol
    lines = urllib2.urlopen(url).read().splitlines()
    return json.loads(''.join([x for x in lines if x not in ('// [', ']')]))


if __name__ == '__main__':
    quote = get_stock_quote('IBM')
    print 'ticker: %s' % quote['t']
    print 'current price: %s' % quote['l_cur']
    print 'last trade: %s' % quote['lt']
    print 'full quote:'
    pprint.pprint(quote)

* note: all values in the returned dict object are Unicode strings.

Output:

ticker: IBM
current price: 174.51
last trade: Sep 26, 4:00PM EDT
full quote:
{u'c': u'+5.17',
 u'ccol': u'chg',
 u'cp': u'3.05',
 u'div': u'0.75',
 u'e': u'NYSE',
 u'ec': u'0.00',
 u'eccol': u'chb',
 u'ecp': u'0.00',
 u'el': u'174.51',
 u'el_cur': u'174.51',
 u'elt': u'Sep 26, 6:07PM EDT',
 u'id': u'18241',
 u'l': u'174.51',
 u'l_cur': u'174.51',
 u'lt': u'Sep 26, 4:00PM EDT',
 u'ltt': u'4:00PM EDT',
 u's': u'2',
 u't': u'IBM',
 u'yld': u'1.72'}
 

Open Source Code Visualization With code_swarm (Canonical, Selenium, Couchbase)

After a bit of hacking, I got code_swarm visualizations running on my Ubuntu 11.04 box. I'm capturing some pretty cool videos from source repos in git, bzr, and svn. Here are some of the more interesting code-base visualization videos I've made:

Canonical:

* Unity (2009-10-15 - 2011-08-28) [1 min 58 secs]
* Launchpad (2004-06-22 - 2011-08-28) [7 mins 22 secs]

Selenium WebDriver:

* Selenium trunk (2009-11-22 - 2011-08-29) [1 min 52 secs]

Couchbase:

* membase ns_server (2011, Aug 27) [1 min 45 secs]

Python - Getting Started With Selenium WebDriver on Ubuntu/Debian

This is a quick introduction to Selenium WebDriver in Python on Ubuntu/Debian systems.

WebDriver (part of Selenium 2) is a library for automating browsers, and can be used from a variety of language bindings. It allows you to programmatically drive a browser and interact with web elements. It is most often used for test automation, but can be adapted to a variety of web scraping or automation tasks.

To use the WebDriver API in Python, you must first install the Selenium Python bindings. This will give you access to your browser from Python code. The easiest way to install the bindings is via pip.

On Ubuntu/Debian systems, this will install pip (and dependencies) and then install the Selenium Python bindings from PyPI:

 
$ sudo apt-get install python-pip
$ sudo pip install selenium

After the installation, the following code should work:

 
#!/usr/bin/env python

from selenium import webdriver

browser = webdriver.Firefox()
browser.get('http://www.ubuntu.com/')

This should open a Firefox browser sessions and navigate to http://www.ubuntu.com/

Here is a simple functional test in Python, using Selenium WebDriver and the unittest framework:

 
#!/usr/bin/env python

import unittest
from selenium import webdriver


class TestUbuntuHomepage(unittest.TestCase):
    
    def setUp(self):
        self.browser = webdriver.Firefox()
        
    def testTitle(self):
        self.browser.get('http://www.ubuntu.com/')
        self.assertIn('Ubuntu', self.browser.title)
        
    def tearDown(self):
        self.browser.quit()


if __name__ == '__main__':
    unittest.main(verbosity=2)

Output:

 
testTitle (__main__.TestUbuntuHomepage) ... ok

----------------------------------------------------------------------
Ran 1 test in 5.931s

OK

Python - Reading MP3 Meta Information with 'mpeg1audio'

'mpeg1audio' is a Pure Python MPEG Audio Layer 1, 2 and 3 meta information retrieval package. It is capable of retrieving duration, bitrate, average bitrate, sample count, etc.

Here is an example of using mpeg1audio for getting meta data from a directory of MP3 files.

Code:

 
#!/usr/bin/env python

import glob
import mpeg1audio  # (https://github.com/Ciantic/mpeg1audio/)

for f in sorted(glob.glob('*.mp3')):
    mp3 = mpeg1audio.MPEGAudio(f)
    mb = '%.2f' % (mp3.size / 1048576.0)
    fn = f.replace('.mp3', '')
    print '%s (%s) [%dk] %s MB' % (fn, mp3.duration, mp3.bitrate, mb)

Output:

 
Eminem - Buffalo Bill (0:03:56) [253k] 7.15 MB
Minor Threat - Betray (0:03:02) [180k] 3.92 MB
Social Distortion - Bakersfield (0:06:24) [320k] 14.68 MB
Social Distortion - Diamond In The Rough (0:04:34) [320k] 10.49 MB
Social Distortion - Prison Bound (0:05:24) [227k] 8.81 MB
Social Distortion - When She Begins (0:05:02) [320k] 11.54 MB

Python - processing GMail IMAP email

Here is an example of processing your GMail IMAP email in Python.

The script below will:

• login to GMail account using IMAP
• open your Inbox
• retrieve and print all messages
• close mailbox
• logout

#!/usr/bin/env python

import imaplib

USER = 'username@gmail.com'
PASSWORD = 'xxx'

mail = imaplib.IMAP4_SSL('imap.gmail.com', 993)
mail.login(USER, PASSWORD)
mail.select('Inbox')

status, data = mail.search(None, 'ALL')
for num in data[0].split():
    status, data = mail.fetch(num, '(RFC822)')
    print 'Message %s\n%s\n' % (num, data[0][1])
   
mail.close()
mail.logout()

Joined Google+

I have an account on Google+
Go ahead and add me if you know me :)

• http://gplus.to/cgoldberg
• https://plus.google.com/u/0/114546378907380458640

Python - Taking Browser Screenshots With No Display (Selenium/Xvfb)

In my last two blog posts, I showed examples of using Selenium WebDriver to capture screenshots, and running in a headless (no X-server) mode.

This example combines the two solutions to capture screenshots inside a virtual display.

To achieve this, I use a combination of Selenium WebDriver and pyvirtualdisplay (which uses xvfb) to run a browser in a virtual display and capture screenshots.

the setup you need is:

• Selenium 2 Python bindings: PyPI
• pyvirtualdisplay Python package (depends on xvfb): PyPI

On Debian/Ubuntu Linux systems, you can install everything with:

$ sudo apt-get install python-pip xvfb xserver-xephyr
$ sudo pip install selenium

once you have it setup, the following code example should work:

#!/usr/bin/env python

from pyvirtualdisplay import Display
from selenium import webdriver

display = Display(visible=0, size=(800, 600))
display.start()

browser = webdriver.Firefox()
browser.get('http://www.google.com')
browser.save_screenshot('screenie.png')
browser.quit()

display.stop()

this will:

• launch a virtual display
• launch Firefox browser inside the virtual display
• navigate to google.com
• capture and save a screenshot
• close the browser
• stop the virtual display

Python - Headless Selenium WebDriver Tests using PyVirtualDisplay

I need to integrate my functional UI tests (Selenium/WebDriver) with my Jenkins CI system. The problem is that my Jenkins CI server has no display, so I must run my GUI tests in a headless X-server.

A colleague pointed me to PyVirtualDisplay, a Python wrapper for Xvfb and Xephyr.

This makes running headless Python Selenium/WebDriver tests very easy.

Here is some Python code showing WebDriver with a virtual display provided by Xvfb:

    
#!/usr/bin/env python

from pyvirtualdisplay import Display
from selenium import webdriver

display = Display(visible=0, size=(800, 600))
display.start()

# now Firefox will run in a virtual display. 
# you will not see the browser.
browser = webdriver.Firefox()
browser.get('http://www.google.com')
print browser.title
browser.quit()

display.stop()

install PyVirtualDisplay on Ubuntu/Debian:

$ sudo apt-get install xvfb python-pip
$ sudo pip install pyvirtualdisplay

Python - Selenium WebDriver - Capture Screenshot

Example of capturing a screenshot from Selenium WebDriver in Python:

 
#!/usr/bin/env python
from selenium import webdriver

browser = webdriver.Firefox()
browser.get('http://www.ubuntu.com/')
browser.save_screenshot('screenie.png')
browser.quit()

selenium/webdriver bindings for Python: http://pypi.python.org/pypi/selenium

Ubuntu Developer Summit, Oneiric Ocelot

I just got back from UDS-O (Ubuntu Developer Summit, Oneiric Ocelot) in Budapest, Hungary. It was my first UDS, and my first time in Eastern Europe.

I was really worried that the time-change and jet-lag going to eastern Europe would mess me up. However, I felt really good the entire trip and adjusted almost instantly. My mood was good and I was ready to hack.

Some quick comments about the summit:

• Budapest was fun and interesting, with beautiful weather and historic architecture.
• The Ubuntu summit is a very well run event, where important decisions are made and work gets done.
• Our Community rocks!
• Ubuntu rocks!

I was able to attend a few UDS sessions throughout the week, but my main mission was an on-site sprint with my team at Canonical (ISD). Our team is globally-distributed, and this was my first chance to meet and work with all of them in person. While the entire summit was awesome, my most lasting memories will be of sitting crammed in a hot hotel room with a dozen of the finest hackers/colleagues I have ever worked with. As a new member to ISD, they made me feel welcomed and let me jump right in.

Can't wait until next UDS!

Performance and Scalability Testing with Python and Multi-Mechanize

I put together a slide-deck to help introduce Multi-Mechanize. I wanted something a little friendlier and easier to digest than "go read the project wiki". (It is also the basis of a presentation/talk I might give someday).

Hopefully, this will help people better understand what the project is all about.

Performance and Scalability Testing with Python and Multi-Mechanize

linux-metrics - Python Package - System Metrics/Stats for Linux

I just released my Python package: 'linux-metrics'

linux-metrics contains Python modules for getting OS metrics on systems running the Linux (2.6) kernel. It is a pure python library with no external dependencies.

This project is under development, and nowhere near comprehensive. Only basic stats for major subsystems are provided (Processor/CPU, Disk, Memory, Network). Hopefully, more are coming.

• Project Home: http://linux-metrics.googlecode.com
• PyPI Entry: http://pypi.python.org/pypi/linux-metrics