Environment Config

This module allows you to override configuration on a per-environment basis.

Motivation

In Drupal 8, settings are managed in one of two ways.

• The Configuration API is for "Configuration is a place to store information that you would want to synchronize from development to production." (https://www.drupal.org/docs/8/api/configuration-api/configuration-api-ov...).
• The State API is for settings "specific to an individual environment." (https://www.drupal.org/docs/8/api/state-api)

In most cases this is fine, however it does rely on module developers knowing ahead of time whether your use of their module will require a setting to be the same across all environments (ie stored with Configuration API) or differ across environments (ie stored with the State API). In some cases you'll want to manage a Configuration setting on a per-environment basis (eg use a different API key on different environments) - if so, this module is for you.

This enables you to manage per-environment configurations in your infrastructure configuration management tool (eg ansible) by using that tool to maintain the yaml file and setting the DRUPAL_CONFIG_DIR environment variable to the correct value.

Usage

• Install the module
• Create a directory to contain your environment-specific settings.
• Set the environment variable DRUPAL_CONFIG_DIR to the name of the directory you created. (NB this can be outside of the document root).
• Create configuration management yaml files containing only the configuration settings that you wish to override. eg to modify the api_key setting of the foo_bar.settings configuration create a file called 'foo_bar.settings.yml' containing the following:
  api_key: ABCDE12345
• When the cache is next rebuilt your new settings will be saved into the active configuration.

Notes

• IF YOU EXPORT YOUR ACTIVE CONFIGURATION (eg by running drush cex) THEN YOUR ENVIRONMENT-SPECIFIC CONFIGURATION WILL BE EXPORTED. This will not usually be a problem provided you have the same set of environment-specific configurations on each environment you deploy to (because the exported setting will be overridden by their environment-specific counterparts).
• Pro tip: Use drush (or console) to create your initial yaml files then edit as appropriate. eg drush cget foo_bar.settings > my/environment/config/dir/foo_bar.settings.yml
• An alternative approach to using this module would be to modify your build/deploy scripts to call a command to set these manually (eg drush cset foo_module.settings api_key ABCDE12345)

Todo

• Need to check for more use cases (eg setting complex objects).
• Currently only one file per environment is possible - won't work if eg dev and stage are on the same machine as they'll be sharing the DRUPAL_CONFIG environment variable.