This document contains information about using Cloud Platform environment variables in your application.
Cloud Platform makes environment variables available for your use in both your application code and Drush commands. With these variables, you can write code that responds to the environment in which it runs. For example, you may want to run certain commands only in your production environment, but not in the development or staging environment.
Additional environment variables are available for Pipelines.
In addition to the environment variables provided by Cloud Platform, you can provide information to your application by creating custom environment variables in the Cloud Platform interface, or by storing private information in the file system.
Available environment variables
Cloud Platform includes the following environment variables:
| Variable | Format | Description | Values |
|---|---|---|---|
AH_SITE_GROUP | string | The site name or the Unix user. | |
AH_SITE_ENVIRONMENT | string | The type of the Cloud Platform environment. |
|
AH_PRODUCTION | string | The variable that indicates whether this environment is a production environment. |
|
AH_NON_PRODUCTION | string | The variable that indicates whether this environment is a non-production environment. |
|
AH_CURRENT_REGION | string | The Amazon Web Services region where the web infrastructure processing the current request is running. | |
AH_REALM | string | The realm where the application is running. | |
AH_SITE_NAME | string | The environment name. | |
HTTP_X_REQUEST_ID | string | The unique request ID assigned to every web request received by Cloud Platform. This is set in the HTTP header X-Request-ID. For more information, see Using HTTP request IDs. | |
MAGICK_MEMORY_LIMIT | string | The memory limit for ImageMagick. | |
PATH | string | The location of all the executable for the environment. If you configure an environment to use a specific version of PHP, that version of PHP is first in the path. | |
TEMP | string | The temporary directory for the environment. This directory is located at /mnt/tmp/[site].[env]. Use this variable instead of /tmp because /tmp is smaller and may fill up rapidly. |
Environment variables in .htaccess
You can also use environment variables in your .htaccess file. In the following example, we redirect HTTP requests to HTTPS only on the production environment, and not in the development or staging environments:
RewriteCond %{HTTPS} off
RewriteCond %{HTTP:X-Forwarded-Proto} !https
RewriteCond %{ENV:AH_SITE_ENVIRONMENT} prod
// Site Factory may require a different value for
// %{ENV:AH_SITE_ENVIRONMENT} depending on site configuration
RewriteRule ^(.*)$ https://%{HTTP_HOST}%{REQUEST_URI} [L,R=301]
For more information, see Excluding Acquia domains and non-production environments.
Faking your environment variables for local testing
During testing, you may want to force a Cloud Platform environment variable to contain a specific value by making a change to your local settings.php file. The following example sets the AH_SITE_ENVIRONMENT variable to the dev environment:
$_ENV['AH_SITE_ENVIRONMENT'] = 'dev';
For an example of this technique’s use, see Overriding Solr index connection switching.
Examples
For example, the following statement would let you switch code based on the environment:
if (isset($_ENV['AH_SITE_ENVIRONMENT'])) {
switch ($_ENV['AH_SITE_ENVIRONMENT']) {
case 'dev':
// do something on dev
break;
case 'test':
// do something on staging
break;
case 'prod':
// do something on prod
// Site Factory may require a different value depending
// on site configuration
break;
case 'ra':
// do something on ra - necessary if a
// Remote Administration environment is present
break;
}
}
else {
// do something for a non-Acquia-hosted application
// (like a local dev install).
; }
To make Acquia Search read-only on your Development and Staging environments, so the search index doesn’t have duplicate copies of content:
// place this after the Acquia require line
if (!isset($_ENV['AH_SITE_ENVIRONMENT']) ||
'prod' != $_ENV['AH_SITE_ENVIRONMENT']) {
$settings['acquia_search']['read_only'] = TRUE;
}
For another example, see Setting base URLs.