Riak Function Contrib
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Riak Function Contrib

Riak Function Contrib is a community-powered library of MapReduce, Pre-/Post-Commit Hook, and other functions. It exists for several reasons:

  1. So Riak users can contribute functions they've written back to the community in one centralized, easy-to-manage location
  2. To provide users who are new to Riak with a list of previously-created and tested functions that may suit their usage needs
  3. To lower the barrier to entry to using and mastering MapReduce and Pre-/Post-Commit Hook Functions in Riak


To use the code in this repo you can either browse the source files of the functions in the directory of your choice or head over to the Riak Function Contrib wiki to search for useful code and read in depth descriptions provided by function authors.

Issues or Questions

If, at any point, you have a question or issue, please post to the Riak Mailing List and submit your question there.


Have a function to share with the rest of the Riak Community? Great. Here is how you do it:

  1. Fork this repo to your own GitHub account (You can read up on forking here if you need a refresher)
  2. Branch from master and add your function source file to the appropriate directory (explained in depth below)
  3. Send a pull request against the master branch from your branch
  4. Create your docs branch based on the wiki upstream branch, and add your overview file (again, explained below)
  5. Send a pull request against the wiki branch for your docs contribution
  6. Kick back, smile, and relish in the fact that your functions are helping Riak users everywhere

Your Function Source File

Step 2 above is "Add your function source file to the appropriate directory." The MapReduce Functions live in the mapreduce directory, and are broken up by languages (Erlang or JavaScript). Pre- and Post- Commit source code lives in the hooks directory and is broken down by type (Pre and Post). For instance, if you have a JavaScript MapReduce Function to contribute, it will live in this directory.

What should the source file contain?

  1. Apache 2.0 License Boilerplate. All files submitted to the Riak Function Contrib Repo must include the Apache 2.0 boilerplate. If you're unfamiliar with the Apache license and how to include it in your code, please take a moment and read up on it here.

  2. Your code. This is fairly self-explanatory. In addition to the code, make sure to include adequate comments and notation. Here's a great example.

Your Overview File

In addition to your source, you're encourage to take a few minutes and put together an overview file. Why? Because your contribution to Riak Function Contrib will visible in two locations: 1) as part of the actual code repo in the form of your source file and 2) as an overview page on the Riak Function Contrib wiki For example, the overview page for this function lives here

A General Note on File Naming

Try to name your source file in such a way that it describes what the function might be used for. For example, if the code is a JavaScript reduce function that is good for filtering out large objects, you might name it large-object-filter-reduce.js

Also, be sure to name your overview file with the same name as your source file (save for the extension, of course). So, to continue with the example given above, if your source file is named large-object-filter-reduce.js you would name your overview file Large-Object-Filter-Reduce.md