Henry - A Command Line Tool for Looker Instance Cleanup

[jax1]

The Problem

As a Looker model grows in size and sophistication, it will also experience an ever-increasing number of Explores, Views and Fields. Unfortunately, a common side effect of this is model bloat, which typically means a less than great end-user experience.

The Why

Henry is a command line tool that helps determine model bloat in your Looker instance and identify unused content in models and explores. It is meant to provide recommendations that developers can validate in order to cleanup models from unused explores and explores from unused joins and fields, as well as maintain a healthy and user-friendly instance.

The How

The tool currently has three main commands: pulse, analyze and vacuum.

The pulse command runs a number of tests that help determine the overall health of the Looker instance. Among the tests are: connection checks, which confirm that all connections are in working order; query history checks to determine if there are any whose runtime stands out; the use of any legacy features; schedule plans health; and finally, whether the latest version of Looker is being used.

The analyze command gives the ability to scan projects, models and explores. With projects, it scans their content as well as checks for the status of quintessential features for success such as the git connection status and validation requirements. Whereas with models and explores, it provides statistics around unused explores, joins and fields as well as query count.

Finally, the vacuum command can be used with models and explores and it outputs a list of unused content based on predefined criteria. As an example, if we want to find out what fields are unused in the cohorts explore in the model thelook, we can obtain this by running:

$ henry vacuum explores --model thelook --explore cohorts
which yields:

| model   | explore   | unused_joins   | unused_fields                |
|---------+-----------+----------------+------------------------------|
| thelook | cohorts   | N/A            | order_items.created_date     |
|         |           |                | order_items.id               |
|         |           |                | order_items.total_sale_price |
+---------+-----------+----------------+------------------------------+

The Setup

Henry is on PyPI and the easiest way to install it is by running
pip install henry.

If interested in the implementation or in contributing, the source code can be found in the @jax1.

Please note that this tool is open source and is not supported by Looker’s normal support channels. However, any issues encountered while using the tool are encouraged to be filed here: https://github.com/looker-open-source/henry/issues as it will help contributors enhance it further.