Running "one off" Conversions In PostgreSQL

The other day we needed to runs a one-off job for converting datetime.weekday() values to day names. Here's what we came up with.

Getting Good Errors from Python Map/Reduce Jobs

At work, we use some Python map/reduce jobs (using Hadoop streaming).

Debugging can be difficult, since Hadoop does not keep the Python stacktraces and even if it does - it's very hard to find it. We decided to use crashlog, and now we get wonderful emails with detailed description of what went wrong.

Notes:

• The current mapper input file is in map_input_file environment variable
• Don't forget to add crashlog.py with -file (see here)
• You must add "." to PYTHONPATH in order to import
• import sys; sys.path.append('.') should do the trick
• Email is not the best solution for distributed logging (you get a lot of email when things go South). I'm going to play with graylog2 in the future.

Serving Dynamic Images with matplotlib

Here's an example of generating dynamic images using matplotlib in a web server (flask this time).

Show Location Of Hive Table in HDFS

Here's a script I use to find out where Hive is storing it's data on HDFS (I call it hiveloc).

Quickly Plotting Labeled Data

Here's a quick way to view some labeled data you have (taken from An Introduction to scikit-learn). It will reduce the data to two dimensions using PCA and then scatter plot it with different colors for each label.

Script to close a branch in mercurial (hg)

Mercurial (hg) does not let you delete branches (or alter history in any way). But you can close branches so they won't show in hg branches command.

Here's a script I use to close branches (we work with feature branches at work, and close them when work on the feature is done).

gittip on bitbucket/github

gittip is a cool idea, however currently there's no built-in way to add it to bitbucket/github projects.

One option I found that works it to add a clickable image to your README.md or README.rst.

See example here.

Markdown:

[](https://www.gittip.com/Miki%20Tebeka/)

ReStructuedText:

.. image:: http://i.imgur.com/lg9rx9w.png
   :alt: gittip
   :target: https://www.gittip.com/Miki%20Tebeka/

Notes:

1. You'll probably want to change gittip user id :)
2. There's a discussion on gittip bug tracker on the right way to do this.
3. Unofficial gittip image generated using cooltext.

import "C" slides

Last night I gave a talk about using C from Go at the L.A. Gophers meetup.

You can view the slides here. (Note that "run" won't work due to security restrictions, you can download the slides here and run it locally using the present tool).