Alternate MySQL backend for Hiera

This is a MySQL backend for Hiera inspired by hiera-mysql. Unfortunately no work has been done to that backend for the past 9 months and it was missing a couple of features I needed so I decided to pick up the torch and implement them myself.

In hiera-mysql you define the queries in the hiera.yaml file. I felt this was too restricting so instead hiera-mysql-backend uses, poorly named, sql files. This sql files follow the Hiera hierarchy.

hiera-mysql would also return the last matching query not the first one which I felt it was confusing.

hiera-mysql used the mysql gem, I am partial to mysql2

Exception handling. hiera-mysql would cause a puppet run to fail if one of the queries was incorrect. For example a fact that you are distributing with a module is needed for the query to return its data but that fact is not available outside the module having a SELECT * from %{custom_fact} would make puppet runs fail.

The poorly named sql files are really yaml files where the key is the lookup key and the value is the SQL statement (it accepts interpolation)

As of version 0.0.4 you can also add connection information to these sql files, this allows you to connect to different databases. This is optional if no connection information is found it will use the default defined in your hiera.yaml config.

Lets assume your datadir is /etc/puppet/hieradata/ and your hierarchy for hiera just have a common. hiera-mysql-backend would look for /etc/puppet/hieradata/common.sql the common.sql would look like:

---
# This is optional, if not present it will use the default connection info from hiera.yaml
:dbconfig:
  :host: database.example.com
  :user: hieratest
  :pass: sekret
  :database: testhieradb
  :port: 44445

applications: SELECT * FROM applications WHERE host='%{fqdn}';
coats: SELECT cut,name,type FROM coats WHERE color='brown';

If host is not defined it will use localhost as default.

If port is not defined it will use the default 3306 mysql port

running hiera applications would run the query against the configured database.

gem install hiera-mysql-backend

Hiera configuration is pretty simple

---
:backends:
  - yaml
  - mysql2

:yaml:
  :datadir: /etc/puppet/hieradata

:mysql2:
  :datadir: /etc/puppet/hieradata
  :host: hostname
  :user: username
  :pass: password
  :database: database
  :port: 3306

:hierarchy:
  - "%{::clientcert}"
  - "%{::custom_location}"
  - common

:logger: console

If host is not defined it will use localhost as default.

If port is not defined it will use the default 3306 mysql port

1. It always return an Array of hashes regardless of the number of items returned. (I did this on purpose because it is what I needed but I may be persuaded to do otherwise)
2. This README is poorly written.

1. Fork it
2. Create your feature branch (git checkout -b my-new-feature)
3. Commit your changes (git commit -am 'Add some feature')
4. Push to the branch (git push origin my-new-feature)
5. Create new Pull Request