Multi-tenancy with Ecto, Part 1

With Ecto 2.0, there is support for Postgres schema or multiple databases for MySQL. What I am trying to do here is to use Postgres schema to achieve multi-tenancy, and of course using Ecto. Disclaimer: This is mostly for my personal notes as I try to understand Ecto/Elixir…

Django multi tenant issues with Celery + Postgres

You can quickly build a multi-tenant site in Django with the help of this nifty package django-tenant-schemas. It works by assigning each tenant into its own database schema and having one public schema for anything that needs to be shared. It wraps Django's connection with its own wrapper that help…

Class based Celery task

In the previous post, I showed you how to implement basic Celery task that make use of @task decorator and some pattern on how to remove circular dependencies when calling the task from Flask view. Let's recall some part of the code. def run_task_async(): task = chain(long_run_…

Celery integration with Flask

As of Celery version 3.0 and above, Celery integration with Flask should no longer need to depend on third party extension. That's what they said. However, my experience integrating Celery with Flask especially when using Flask with blueprints shows that it can be a little bit tricky. Challenges So…

Change IP address for existing nodes in CDH 5.3

Today I discovered way to handle changes of IP address for Hadoop cluster managed by CDH 5.3. I think this should also be applicable for CDH 5.x. Took me couple of hours to figure this one out :/ I've done this previously but it was on CDH 4.x.…

Creating Brew external command

Recently I had the need to create a homebrew external command to extend homebrew default behavior. My goal is to extend brew deps command by creating a new command brew deps-group. Executing the command will list all top-level packages in homebrew that is related to each other by common dependencies,…

Kaggle: Bike Sharing Demand Part 1

Finally had a chance to play around with Kaggle challenge, and bike sharing demand seems to be the easiest to tackle - no domain expertise required or atleast very minimal. This is going to be Part 1 where I'll go over how I apply minimal statistical knowledge to extract features.…

Image filtering with convolution matrix

I was reading reading about convolution matrix which was brillianty explained by Colah. If you're looking for good blog to follow, you might want to add him into the list. One of the application of convolution matrix is image manipulation like applying filters to the image. The cool part is…