Andrey Khavryuchenko himself

Breakthrough for carbon nanotube materials – stronger than steel, production up to 7 meters per minute

Image via WikipediaBreakthrough for carbon nanotube materials

as reported in today’s edition of the prestigious international scientific journal, Science – the UTD/CSIRO team recently demonstrated that synthetically made carbon nanotubes can be commercially manufactured into transparent sheets that are stronger than steel sheets of the same weight. [...] Starting from chemically grown, self-assembled structures in which nanotubes are aligned like trees in a forest, the sheets are produced at up to seven meters per minute

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Test driven bug fixing

Image by Lachlan Hardy via FlickrI wonder that too many developers misunderstand steps to approach a bug in test driven development fashion.

They’re dead simple:

1. Reproduce the bug manually
2. Write automated test that reproduces the bug
3. Commit this test – nice step when using easy-branching git and doing your changes in a separate branch
4. Fix the bug and make test pass
5. Commit the fix
6. Check the behaviour manually

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Is face-to-face communication really always better?

Image via WikipediaCommunicating Persuasively: Email or Face-to-Face?

Our intuitive understanding is that face-to-face communication is the most persuasive. In reality, of course, it’s not always possible to meet in person, so email wins out. How, then, do people react to persuasion attempts over email? Persuasion research has uncovered fascinating effects: that men seem more responsive to email because it bypasses their competitive tendencies (Guadagno & Cialdini, 2002). Women, however, may respond better in face-to-face encounters because they are more ‘relationship-minded’.

I don’t know a gender composition of your development team, but ours is 100% men.

More work, less status games?

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More on doing software in distributed team

“We want people to stay away from each other and actually get the work done.” — Jason Fried, 37Signals (in the interview with O’Reilly’)

I have nothing to add

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Where’s a distributed team pain?

Recently I’ve read a bunch of posts regarding pain and sub-optimality of a distributed team developing software:

• Distribute the team? Distribute the pain!
• on distributed teams
• New Release: Distributed Agile Development at Microsoft patterns & practices
• Learning and Distributed teams
• Tools for Distributed Teams

Actually we do run all our development with distributed team and I’m not experiencing much pain.

Instead of commuting 1-2 hours (one way) to office, just like a photo below , we work in the comfort of our homes at time we’ve agreed to work. Something in line of the picture above Image via Wikipedia

Yes, comparing to an office, we may lack a nonverbal communication. But we compensate it with being 100% present on jabber/skype, reviewing each other code and applying few other techniques to glue together a distributed team.

Nevertheless, each of post, I’ve seen says that collocated team is better.

Why it should, if we might lose, say, 5% in productivity and gain 2-3 additional work hours per day (25-38% increase)?

What I’m doing wrong that I don’t have that pain?

Posted in Business, Software Development | 11 Comments »

twill + rss

Rerunning my old post about testing django with twill, since I’ve seen this issue raised again.

…

Now have a pleasure of not starting django development webserver, nor using apache to do http-level tests in my project.

Thanks to twill and its wsgi integration.

Works smoothly now, but caused me little cursing when twill refused to see rss feed.

After digging the twill code I’ve changed a single line – still don’t know how correct is this:

--- /usr/lib/python2.4/site-packages/twill-0.9b1-py2.4.egg/twill/wsgi_intercept.py.orig 2007-06-04 21:10:37 +0300
+++ /usr/lib/python2.4/site-packages/twill-0.9b1-py2.4.egg/twill/wsgi_intercept.py      2007-06-04 21:10:45 +0300
@@ -265,7 +265,7 @@
                 for data in self.write_results:
                     self.output.write(data)

-            if generator_data:
+            if generator_data is not None:
                 self.output.write(generator_data)
                 for data in self.result:
                     self.output.write(data)

Nevertheless it didn’t break anything and I have a luxury to test rss feeds too:

# -*- coding: utf-8 -*-
# $Id: tests.py 326 2007-06-04 15:58:48Z akhavr $

from nose.tools import *
from twill.commands import *
from twill import add_wsgi_intercept

def setup():
    import os
    os.environ["DJANGO_SETTINGS_MODULE"] = "web.settings"

    from django.core.servers.basehttp import AdminMediaHandler
    from django.core.handlers.wsgi import WSGIHandler

    app = AdminMediaHandler(WSGIHandler())
    add_wsgi_intercept("127.0.0.1", 9876, lambda: app)

@with_setup(setup)
def test_rss():
    'test rss feed'
    go('http://127.0.0.1:9876/kds-djangofeed/feed/rss/')
    code('200')
    find('<rss version="2.0"><channel><title>Django Feed Planet.</title>')
    return

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Our first startuplet – code review service

Welcome, reviework.com.

This is a simple code discussion service working with git repositories and, through git adapters – with any other VC supported. SVN would be added, of course, the first.

Right now we are using actively it in our own internal development and working with few selected teams to polish the user interface and workflow.

Now, check the screenshots (clickable).

Posted in Business, Django, Microentry, Python, Software Development, Startuplet, Startups | No Comments »

Webware encoding issues also known as “UnicodeDecodeError: 'ascii' codec can't decode”

Setup:

1. You have html snippets with unicode.
2. Your application is written in webware that some time ago was forked from main development
3. You have to show this unicode text to user

Result:

Something like:

File "....app/Webware/WebKit/HTTPResponse.py", line 370, in rawResponse [edit]
     return {
File "..../app/Webware/WebKit/ASStreamOut.py", line 96, in buffer [edit]
     return ''.join(self._chunks)
UnicodeDecodeError: 'ascii' codec can't decode byte 0xc3 in position 22:
ordinal not in range(128)

Or, something in line with this experience.

Solution that worked for us:

Change

        return ''.join(self._chunks)

to

        #This is dirty hack to correctly operate with utf8
        new_chunks = []
        for chunk in self._chunks:
            try:
                _chunk = chunk.encode('ascii', 'xmlcharrefreplace')
            except:
                import chardet
                _chunk = unicode(chunk, chardet.detect(chunk)("encoding"]).encode('utf-8')
            new_chunks.append(_chunk)
        self._chunks = new_chunks
        #End of dirty hack
        return ''.join(self._chunks)

It uses chardet library from feedparser project.

Posted in Python, Software Development | No Comments »

Absolutely unscientific comparison of django performance with different caching backends

Image via WikipediaSetup: dead simple django application, returning a template stored in a file as a root page. Template has no executable code.

The server is started as FastCGI (10 children) and server through nginx.

Hardware – IBM T42 with 1GB under linux, kde, firefox, thunderbird, emacs, openoffice and bunch of other everyday application open.

Performance is measured with /usr/sbin/ab -n 10000 -c 10 http://localhost:81/

Results are below.

No cache: (dummy:///)

Requests per second:    219.26 [#/sec] (mean)
Time per request:       45.61 [ms] (mean)
Time per request:       4.56 [ms] (mean, across all concurrent requests)

locmem:///

Requests per second:    302.55 [#/sec] (mean)
Time per request:       33.05 [ms] (mean)
Time per request:       3.31 [ms] (mean, across all concurrent requests)

db://cache

Requests per second:    168.21 [#/sec] (mean)
Time per request:       59.45 [ms] (mean)
Time per request:       5.94 [ms] (mean, across all concurrent requests)

file:///tmp

Requests per second:    12.36 [#/sec] (mean)
Time per request:       808.84 [ms] (mean)
Time per request:       80.88 [ms] (mean, across all concurrent requests)

local memcached with 64Mb

Requests per second:    221.29 [#/sec] (mean)
Time per request:       45.19 [ms] (mean)
Time per request:       4.52 [ms] (mean, across all concurrent requests)
Transfer rate:          81.44 [Kbytes/sec] received

I’ll do no analysis, butwhat surprised me most was the (mis)performance of file:/// backend.

Posted in Django, Software Development, Sysadm | No Comments »

BuildBot and git – peculiarity

Interesting that BuildBot clones git repository in it’s own particular way: there’s no origin/master branch in the resulting repository.

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