Wordpress wp-config.php doesn't update in Dockers? - wordpress

Question

I am using Wordpress and docker container. The problem is that I updated the wp-config.php file but everything looks the same.
I have something like this:
CONTAINER ID IMAGE NAMES
b2711d4b72a1 phpmyadmin/phpmyadmin website_phpmyadmin_1
8a89ee46d673 wordpress:4.7.5 website_wordpress_1
2a167667f705 mysql:5.7 website_db_1
My docker-compose.yaml looks like this:
version: '2'
services:
wordpress:
depends_on:
- db
image: wordpress:4.7.5
restart: always
volumes:
- ./wp-content:/var/www/html/wp-content
environment:
WORDPRESS_DB_HOST: db:3306
WORDPRESS_DB_PASSWORD: p4ssw0rd!
ports:
- 80:80
- 443:443
networks:
- back
db:
image: mysql:5.7
restart: always
volumes:
- db_data:/var/lib/mysql
environment:
MYSQL_ROOT_PASSWORD: p4ssw0rd!
networks:
- back
phpmyadmin:
depends_on:
- db
image: phpmyadmin/phpmyadmin
restart: always
ports:
- 8080:80
environment:
PMA_HOST: db
MYSQL_ROOT_PASSWORD: p4ssw0rd!
networks:
- back
networks:
back:
volumes:
db_data:
I have run docker-compose up, build and down but everything is the same.

Answer 1

The official WordPress docker image will automatically configure wp-config.php using the environment variables you set [documentation].
If there are any variables such as WORDPRESS_DB_HOST, WORDPRESS_DB_PASSWORD, etc., they will be used to build a wp-config.php file upon container creation.
If you want to provide a custom wp-config.php file, you need to make sure there are no related environment variables, and create a volume mapping for your modified file, like so:
version: '2'
...
volumes:
- ./wp-content:/var/www/html/wp-content
- ./wp-config.php:/var/www/html/wp-config.php
...
On docker-compose up, Docker will load your custom wp-config.php into the container and then run the WordPress image's docker-entrypoint.sh which updates the file with the values set in your environment variables.

Answer 2

You can make use of the WORDPRESS_CONFIG_EXTRA environment variable to define any other config values in the wp-config.php file.
As an example:
WORDPRESS_CONFIG_EXTRA: |
define('WP_ALLOW_MULTISITE', true );
define('MULTISITE', true);
define('SUBDOMAIN_INSTALL', false);

Answer 3

The trick:
wp:
image: wordpress:latest
ports:
- 80:80
volumes:
- ./wp-content:/var/www/html/wp-content
- ./wp-config.php:/usr/src/wordpress/wp-config-sample.php
When local wp-config.php changes you should delete /var/www/html/wp-config.php from container, docker will copy it again... but it works!