Delays

Sorry for long pause.

I just stared a new job which is not in Python. My interested was also shifted to Clojure.

I'll try to post here more from time to time, but the frequency be lower for the seen future.

In the meanwhile, keep on hacking!

Getting last N items of iterator

islice allow you to get the first N items of an iterator, but since it doesn't accept negative indexes - you can't use it to get the last N. The solution is very simple - use deque.

Configuring Ubuntu For Asus Eee

Lately I lost my main laptop (belonged to the workplace), my older one allows me to use her Eee for now. The Eee came with Windows 7 starter edition, which I grew tired of fast. I've decided to try Ubuntu on it. Trying not to cause too much damage, I used Wubi.

Installing the main distro went without a problem, and after a reboot I had default Gnome desktop up. What I'm describing next is my attempt to get as much screen real estate as possible. Note that I'm spending most of my time in Firefox and in the shell.

General Setup

• Delete the bottom panel (right click and "Delete This Panel")
• Auto hide the top panel (right click, "Properties" and "Autohide")
• Install "Gnome Do"

Firefox Setup

• Right click on the toolbar, "Customize..." and check "Use small icons"
• Click on the "View" menu and leave only the navigation toolbar
• Uncheck the "Status bar" in the "View" menu
• Install the "Hide Menubar" Firefox addon (clicking on "ALT" will show the menu)
• I use GMail and Google Reader, so "Better GMail" and "Better GReader" addons helped
• Install "Adblock Plus" to get more content inside web pages
• This is just a personal preference, but I think installing "Chromifox Extreme" theme freed up some space as well

Terminal Setup

In the "Edit" menu click on "Profile preferences". And on the "General" tab, uncheck "Show menubar by default on new terminals" (use SHIFT-F10 to get a context menu to enable it)

Two More Things

If your kids play webkinz, install Google Chrome. It works much better there (there's always a scroll bar they can use).

As you probably figured out, I am looking for a job right now. If you know someone who is hiring, please point them to my resume.

translate

curl and couchdb - a love story

CouchDB API is JSON over HTTP. Which makes curl my default tool to play with the database.

Here's a small demo:

import_any

Import any file as a Python module. This is a nice big security risk, so beware ...

from types import ModuleType

def import_any(path, name=None):
    module = ModuleType(name or "dummy")
    execfile(path, globals(), module.__dict__)

    return module

Stress Is Good For You

Tagging last good build in git

git (and mercurial) has a nice feature that you can "move" tags (using -f). At Sauce Labs we use that to have a track of our last good build and the last deployed revision.

In our continuous integration system, we mark the last good build in the last step which is executed only if the test suite passed.

tag-ok-build.sh

#!/bin/bash

# Error on 1'st failure
set -e

tag=last-green-build
revision=$(git rev-parse HEAD)

echo "Tagging $commit as $tag"
git tag -f $tag $commit
git pull origin master
git push --tags origin master

To deploy, we use the following script who also tags the last deployed version.

deploy.sh

#!/bin/bash
# Deploy, meaning sync from last successful build

tag=last-green-build

# Fetch get the latest changes from remote but does not update working
# directory, just the index
git fetch --tags

# Merge to the last successful bulid
git merge ${tag}

# Tag currently deployed revision
git tag -f deployed ${tag}
git push --tags

couchnuke

A simple script to "nuke" a couchdb server, use with care!

#!/bin/bash

# Delete all databases on a couchdb server

# Exit on 1'st error
set -e

if [ $# -gt 1 ]; then
    echo "usage: $(basename $0) [DB_URL]"
    exit 1
fi

URL=${1-http://localhost:5984}

echo -n "Delete *ALL* databases on $URL? [y/n] "
read ans
if [ "$ans" != "y" ]; then
    exit
fi

for db in $(curl -s $URL/_all_dbs | tr '",[]' ' \n  ');
do
    echo "Deleting $db"
    curl -X DELETE $URL/$db
done

Run a temporary CouchDB

One nice solution to isolate tests, it to point the code to a temporary database. Below is a script to launch a new instance of CouchDB on a given port.

#!/bin/bash
# A script to run a temporary couchdb instance

if [ $# -ne 1 ]; then
    echo "usage: $(basename $0) PORT"
    exit 1
fi

port=$1

base=$(mktemp -d)
dbdir=$base/data
config=$base/config.ini
mkdir -p $dbdir

cat <<EOF > $config
[httpd]
port = $port

[couchdb]
database_dir = $dbdir
view_index_dir = $dbdir

[log]
file = ${base}/couch.log
EOF

trap "rm -fr $base" SIGINT SIGTERM

echo "couchdb directory is $base"
couchdb -a $config

Sourcing a shell script

Sometime you want to emulate the action of "source" in bash, settings some environment variables.
Here's one way to do it:

from subprocess import Popen, PIPE
from os import environ

def source(script, update=1):
    pipe = Popen(". %s; env" % script, stdout=PIPE, shell=True)
    data = pipe.communicate()[0]

    env = dict((line.split("=", 1) for line in data.splitlines()))
    if update:
        environ.update(env)

    return env

Showing Solr Search Results Usign jQuery

Solr is a wonderful product. However it does not have a integrated search page (there's one in the admin section, but it's nothing you want to expose).

Luckily, Solr supports JSON results and even JSOP, which means we can do all the code for searching in our web page.

Note that I'm using the Solr demo that comes with the distribution, your search results might have different attributes depending on the schema.

<html>
    <head>
        <title>Solr Search</title>
    </head>
    <body>
        <h3>Solr Search</h3>

        Query: <input id="query" /> 
        <button id="search">Search</button>
        <hr />
        <div id="results">
        </div>
    </body>
    <script src="http://ajax.googleapis.com/ajax/libs/jquery/1.4.2/jquery.min.js"></script>
    <script>
        function on_data(data) {
            $('#results').empty();

            var docs = data.response.docs;
            $.each(docs, function(i, item) {
                $('#results').prepend($('<div>' + item.name + '</div>'));
            });

            var total = 'Found ' + docs.length + ' results';
            $('#results').prepend('<div>' + total + '</div>');
        }

        function on_search() {
            var query = $('#query').val();
            if (query.length == 0) {
                return;
            }

            var url='http://localhost:8983/solr/select/?wt=json&json.wrf=?&' +
                    'q=' + query;
            $.getJSON(url, on_data);
        }

        function on_ready() {
            $('#search').click(on_search);
            /* Hook enter to search */
            $('body').keypress(function(e) {
                if (e.keyCode == '13') {
                    on_search();
                }
            });
        }

        $(document).ready(on_ready);
    </script>
</html>  

To run the Solr demo do extract the distribution, then

cd example 
java -jar start.jar > /dev/null &
cd exampledocs 
./post.sh *.xml

Summarizer

Just a quick note that I've uploaded the code to "Text Summarizer" here.

Parse HTTP Response

Steve commented (justly) that there is no Python library function to parse HTTP transportation. Here is one way to do it:

Publish Buildbot builds to Twitter

Buildbot exposes a simple XMLRPC protocol. Using this we can write a small daemon that pools the build status and publish it somewhere (or do other interesting stuff with it). In our case we'll publish the results to twitter using its publishing API.

#!/usr/bin/env python
# Watch builds on buildbot and publish to twitter

from time import time, sleep
from xmlrpclib import ServerProxy
from urllib import urlopen

user, password = "tebeka", "SECRET_PASSWORD"
bbot_url = "http://buildbot.example.com/xmlrpc"
tweet_url = "http://%s:%s@twitter.com/statuses/update.xml" % (user, password)

def main():
    proxy = ServerProxy(bbot_url)
    last_time = time()

    while 1:
        now = time()
        builds = proxy.getAllBuildsInInterval(last_time, now)
        for build in builds:
            builder, build, status = build[0], build[1], build[5]
            status = "OK" if status == "success" else "BROKEN"
            message = "[%s] build %s is %s" % (builder, build, status)
            urlopen(tweet_url, "status=%s" % message)

        last_time = now if builds else last_time
        sleep(10)

if __name__ == "__main__":
    main()

github-url

#!/bin/bash
# Show github URL for a given file

if [ $# -ne 1 ]; then
    echo "usage: $(basename $0) FILENAME"
    exit 1
fi

if [ ! -e $1 ]; then
    echo "error: can't find $1"
    exit 1
fi

if [ -d $1 ]; then
    cd $1
    dest=.
else
    cd $(dirname $1)
    dest=$(basename $1)
fi

url=$(git config remote.origin.url | cut -d: -f2)
if [ $? -ne 0 ]; then
    echo "error: can't get remote url"
    exit 1
fi
url=${url/.git/}

path=$(git ls-files --full-name $dest | head -1)
if [ $? -ne 0 ]; then
    echo "error: git does not know about $1"
    exit 1
fi

branch=$(git branch --no-color 2>/dev/null | grep '^* ' | sed 's/* //')
prefix="https://github.com/$url"
if [ "$dest" == "." ]; then
    path=$(dirname $path)
    url="${prefix}/tree/${branch}/$path"
else
    url="${prefix}/blob/${branch}/$path"
fi

echo $url

Making TeamSpeak 3 work on Ubuntu

 TeamSpeak 3, you can download the Linux client from their site. The only problem is that currently (beta8) the client don't play nice with pulseaudio.

EDIT: Seems like beta-20 is working well with Ubuntu 10.4. Use the ts3client_runscript.sh (make sure you change directory to the TeamSpeak directory first).

After digging in the Ubuntu forums (can't find the exact post link), I came with the following solution:

• Extract the client (cd /opt && sh ~/Downloads/TeamSpeak3-Client-linux_amd64-3.0.0-beta8.run)
• Create the following script

#!/bin/bash

# Make teamspeak work on Ubuntu (basically disable pulseaudio before launching)

conf=$HOME/.pulse/client.conf
backup="${conf}.bak"

if [ -f "$conf" ]; then
    mv "$conf" "$backup"
fi
echo "autospawn = no" > "$conf"
pulseaudio --kill

cleanup() {
rm "$conf"
if [ -f "$backup" ]; then
        mv "$backup" "$conf"
fi
    pulseaudio -D
}

cd /opt/TeamSpeak3-Client-linux_amd64/
./ts3client_linux_amd64&
pid=$!
trap "kill -9 $pid; cleanup" SIGINT SIGTERM
wait $pid
cleanup

Good luck! (The other option is to use mumble.)

Multi VCS status

Since I use mercurial, git, subversion and sometimes bzr. I use the following script (called st) to find the status of the current directory.

#!/bin/bash

# Repository status

root=$PWD
while [ "$root" != "/" ];
do
    if [ -d "$root/.hg" ]; then
        hg status 
        break
    fi
    if [ -d "$root/.git" ]; then
        git status --untracked-files=no
        break
    fi
    if [ -d "$root/.svn" ]; then
        svn status
        break
    fi
    if [ -d "$root/.bzr" ]; then
        bzr status
        break
    fi
    root=$(dirname "$root")
done

if [ "$root" == "/" ]; then
    echo "error: can't find a repository here"
    exit 1
fi

Add Subversion files to git

I you need to start a git repository from a Subversion one, and you don't care about history. Then the following should be helpful.

#!/usr/bin/env python

# Add subversion repsotory to a git one
# Run (at top of svn repository)
#   git init
#   git-add-svn
#   git ci -a -m "Initial import from svn $(svn info | grep Revision)"

__author__ = "Miki Tebeka <miki@mikitebeka.com>"

from os import walk
from os.path import join
from fnmatch import fnmatch
from itertools import ifilter
from subprocess import call
from sys import stdout
import re

is_vcs = re.compile("\.(git|svn)", re.I).search

def make_pred(exclude):
    def is_ok(name):
        return not any((fnmatch(name, ext) for ext in exclude))
    return is_ok

def all_files():
    for root, dirs, files in walk("."):
        if is_vcs(root):
            continue
        for name in files:
            yield join(root, name)

def git_add_svn(exclude):
    pred = make_pred(exclude)
    for filename in ifilter(pred, all_files()):
        print filename
        stdout.flush()
        call(["git", "add", "-f", filename])

def main(argv=None):
    import sys
    from optparse import OptionParser

    argv = argv or sys.argv

    parser = OptionParser("%prog [options]")
    parser.add_option("-e", "--exclude", dest="exclude", action="append",
            help="extension to exclude")

    opts, args = parser.parse_args(argv[1:])
    if args:
        parser.error("wrong number of arguments") # Will exit

    git_add_svn(opts.exclude or [])


if __name__ == "__main__":
    main()

Making GMail The Default Email Application On Ubuntu

• Open System->Preferences->Preferred Applications
• Change "Mail Reader" to "Custom"
• Write bash -c 'to="%s"; gnome-open "https://mail.google.com/mail?view=cm&tf=0&to=${to#mailto:}"' in the "Command:" box