lafentres / mini-etl-challenge

Mini ETL

This program reads comma-separated lines from standard input, parses them, transforms the data, and prints the transformation to standard output.

Each comma-separated line represents an item, its ID, and the ID of its parent item.

The input is guaranteed to be well formed, meaning:

• There is a single root item; there are no orphans.
• There are no cycles.
• There are no commas within an item name, ID, or parent ID.
• No item is duplicated.
• No two items have the same ID.
• The root of the hierarchy has a parent equal to "nil"
• The input does not have a header row

Ruby version

2.5.1

Usage

You can run this program two ways:

1. Provide a file of lines, each separate by a newline, where each line is in the format <ITEM NAME>,<ITEM ID>,<ITEM'S PARENT ID>

   ruby mini_etl.rb sample_input_space.rb
   

OR

2. Run the program and type each line in the console, where each line is in the format <ITEM NAME>,<ITEM ID>,<ITEM'S PARENT ID>. When you are done entering lines, send the EOF signal, CTRL+D.

   ruby mini_etl.rb
   feelings,98473,nil
   ...
   sad,what-a-strange-id,98473
   ^D
   

Things left to improve

• Add tests, in particular for edge cases, larger inputs, etc
• Double-check that the process used is the most efficient
• Refactor to get rid of global variable
• Add a helpful prompt for users providing input through the console
• Add more checks and error handling around file reading
• Add a help/usage command