Environment based local.xml merging

[Vinai]

Support merging an additional local.xml file based on the value of
the MAGE_APPLICATION_ENV environment variable.
The name of the file will be built as follows:

'app/etc/local.' . $_SERVER['MAGE_APPLICATION_ENV'] . '.xml'

The value of the variable is checked to contain only letters,
characters, underscores and dashes.
The file will be merged after the regular local.xml file.

The background idea is described by Matthias Zeis at
#7

[mzeis]

Thanks Vinai for the implementation.

I tested these scenarios successfully:

• use a different adminhtml frontName
• use a different database name

If somebody wants to try this, follow these steps:

• clone Vinais repository (https://github.com/Vinai/magento2.git) and checkout branch local.xml-override
• install Magento
• disable caches (this one is important as the config will be cached)
• add MAGE_APPLICATION_ENV to your vHost config or .htaccess
  • e.g. SetEnv MAGE_APPLICATION_ENV dev
  • If you use .htaccess, edit the file in the Magento root directory, not pub/.htaccess
• add your environment local.xml (e.g. local.dev.xml) and override the settings you want to test

[magento-team]

Instead of applying the proposed patch, we have implemented it in different way.

Most of modifications will be concentrated in loadBase() method. New algorithm:

1. Scan app/etc directory for all files with .xml extension
2. Merge all the found files, except local.xml, in alphabetical order
3. If the local.xml is found – merge it after all the files
4. If the configuration option (Mage_Core_Model_Config_Options) "local_config" is provided (originates from MAGE_LOCAL_CONFIG environment variable), assess if it matches pattern and load additional file:

• Pattern: alphanumeric or dash or underscore, then "/", then again alphanumeric or dash or underscore, then ".xml"
• The file will be loaded only if local.xml has been loaded. If local.xml doesn't exist, the file will not be loaded.
• If the declared file not found, it will be skipped.

This change will be rolled out in one of next updates.
Thank you for the idea and actual suggested implementation.

[Vinai]

Thank you for the detailed answer!
The patch isn't in the current version of github yet, is it?
I like the idea of MAGE_LOCAL_CONFIG to configure config options, but is it possible to specify an php array using, lets say apache mod_env?