Drupal Environment Variables
In our hosting environment we use a core Drupal 8 Docker container replicated across Amazon EC2 instances with Elastic Container Service. Each of these sites is technically a fully functional independent site with its own domain name, 3 seperate environments, and independent Drupal 8 configuration. So how do we achieve these different site requirements with a single Drupal 8 core Docker container? We can start by using environment variables.
Docker Compose
Docker Compose allows us to launch a docker container from an image using a .yml file to define the configuration.
Here's a sample docker-compose.yml used to launch a website in our environment. Specifically see the drupal -> environment section to see environment variables.
docker-compose.yml
version: "2.1"
services:
drupal_db:
image: mysql:5.7
container_name: drupal_db
environment:
MYSQL_ROOT_PASSWORD: drupal
drupal:
image: drupal_core:latest
container_name: drupal
ports:
- 8088:80
environment:
DB_NAME: "drupal"
DB_USER: "root"
DB_PASS: "drupal"
DB_HOST: "drupal_db"
S3_BUCKET: ""
S3_ROOT_FOLDER: "local"
S3FS_ACCESS_KEY: ""
S3FS_SECRET_KEY: ""
SITE_NAME: "Drupal Core - LOCAL"
API_KEY: ""
links:
- drupal_db
When the docker container is lauched via docker-compose these variables will be avaialbe as ENV variables in your hosting environment. These can be accessed in PHP via getenv("env_var").
Consuming ENV with settings.php
Include a local.settings.php to extend settings.php. use getenv() to pull the ENV variables into PHP and then apply to Drupal configuration.
Database Settings
//Database
$dbName=getenv("DB_NAME");
$dbUser=getenv("DB_USER");
$dbPass=getenv("DB_PASS");
$host=getenv("DB_HOST");
//apply those variables
$databases['default']['default'] = array (
'database' => $dbName,
'username' => $dbUser,
'password' => $dbPass,
'prefix' => '',
'host' => $host,
'port' => '',
'namespace' => 'Drupal\\Core\\Database\\Driver\\mysql',
'driver' => 'mysql',
);
S3 Settings
//S3
$s3Bucket=getenv("S3_BUCKET");
$s3RootFolder=getenv("S3_ROOT_FOLDER");
$s3AccessKey=getenv("S3FS_ACCESS_KEY");
$s3SecretKey=getenv("S3FS_SECRET_KEY");
//apply those variables
$config['s3fs.settings']['bucket']=$s3Bucket;
$config['s3fs.settings']['root_folder']=$s3RootFolder;
$settings['s3fs.access_key']=$s3AccessKey;
$settings['s3fs.secret_key']=$s3SecretKey;
$settings['s3fs.use_s3_for_public'] = TRUE;
Site Specifics
$config['system.site']['name'] = getenv("SITE_NAME");
Environment Variables Breakdown
The follow table lists and describes each environment variable we use to customize Drupal 8.
| Environment Variable | Purpose |
|---|---|
| DB_NAME | The database name this site uses |
| DB_PASS | The password for the database |
| DB_HOST | The hostname for the database. If running locally typically this is a linked docker container. If hosting in the cloud (AWS) use the host name |
| DB_HOST | The hostname for the database. If running locally typically this is a linked docker container. If hosting in the cloud (AWS) use the host name |
| S3_BUCKET | The s3 bucket where your images and assets will be stored |
| S3_ROOT_FOLDER | The folder inside S3_BUCKET. This is typically environment specific, DEV/STG/PROD |
| S3FS_ACCESS_KEY | The AWS access key used to upload files to S3_BUCKET. This is required along with the S3FS_SECRET_KEY |
| S3FS_SECRET_KEY | The AWS secret used to upload files to S3_BUCKET. This is required along with the S3FS_ACCESS_KEY |
| SITE_NAME | The name of the site. Visible via the Drupal template |
| API_KEY | Used to connect to AWS API Gateway |