Category: Programming

A big part of my work has to do with code. I’ve worked as system administrator – installing, patching, and configuring someone else’s code. I’ve worked as independent programmer, writing code on my own. I also programmed as part of the team. And on top of that, I worked as Team Leader and Project Manager, where I had to interact a lot with programmers. Programming world on its own is as huge as the universe. There is always something to learn. When I find something worthy or something that I understand enough to write about, I share it in this category.

YANG – A Data Modeling Language for the Network Configuration Protocol (NETCONF)

In the spirit of validating everything against a schema (validating JSON, validating CSV), here is another option – YANG:

YANG is a data modeling language for the definition of data sent over the NETCONF network configuration protocol. The name is an acronym for “Yet Another Next Generation”. The YANG data modeling language was developed by the NETMOD working group in the Internet Engineering Task Force (IETF) and was published as RFC 6020 in October 2010. The data modeling language can be used to model both configuration data as well as state data of network elements. Furthermore, YANG can be used to define the format of event notifications emitted by network elements and it allows data modelers to define the signature of remote procedure calls that can be invoked on network elements via the NETCONF protocol. The language, being protocol independent, can then be converted into any encoding format, e.g. XML or JSON, that the network configuration protocol supports.

YANG is a modular language representing data structures in an XML tree format. The data modeling language comes with a number of built-in data types. Additional application specific data types can be derived from the built-in data types. More complex reusable data structures can be represented as groupings. YANG data models can use XPATH expressions to define constraints on the elements of a YANG data model.

Like many other standards, formats, and tools developed by very smart people, YANG can be used for much more than just networking configuration.  If you data and states fit into its model, give it a try.

Here are a few resources that you might find useful in the process:

Linux utils that you might not know

Linux utils that you might not know covers a few Linux command line utilities that aren’t very famous:

  • column, for “columnating” lists, which is very useful for display of table-like data (think CSV, for example);
  • cal, for displaying calendars;
  • factor, for calculating factors;
  • numfmt, for formatting numbers and converting them to/from human-readable formats;
  • shred, for overwriting the content of a deleted file, making it much more difficult to recover.

JPEG Huffman Coding Tutorial

I came across this rather useful and practical tutorial on Huffman Coding in JPEG images.  It looks at a very small and basic black-and-white image, and how the size of the data and overhead changes between different image formats, and then in more detail, how the Huffman Coding helps make that happen.

Unless you are dealing with compression, image formats, and binary trees on a daily basis, this tutorial is a good memory refresher of those college days.

Boostnote – Open Source note-taking app for programmers

Boostnote is yet another alternative for taking notes.   This one is an Open Source and is built for developers.  Some of the features – Markdown support, search, cross-platform, works offline.

There is also Boostnote Team edition for, you know, teams.