How to copy local wp-content files to Wordpress container using Dockerfile - wordpress

Question

I have a Wordpress container that I would like to copy local folders (with files) to at startup
I have local files in folders:
/html/wp-content/plugins
/html/wp-content/themes
/html/wp-content/uploads
I have a Dockerfile with:
FROM wordpress
COPY ./html/wp-content/plugins/ /var/www/html/wp-content/plugins
COPY ./html/wp-content/themes/ /var/www/html/wp-content/themes
COPY ./html/wp-content/uploads/ /var/www/html/wp-content/uploads
ENTRYPOINT ["docker-entrypoint.sh"]
CMD ["apache2-foreground"]
Although the COPY is succeeding (the build passes), the files are not showing up in these destination folders.
If I change the destination folders to be on any path before /html, eg if I put the destination to be /var or /var/www, then the files copy and I can see them in the container.
I checked out this old post here, which mentions that the /html folder is actually mounted as a volume at startup, and so I need to copy the files into this folder first
/usr/src/wordpress/wp-content
and then at startup these folders will be automatically copied across to /var/www/html/wp-content/. (This would explain why copying directly does not seem to work)
I tried that too, and while my local folders are indeed copied into these folders (I can see them in the container), they are then not copied across to /var/www/html/content at startup!
Is it possible to copy the local files directly into the /var/www/html folders via the dockerfile?
If not, how can I ensure that if copying to /usr/src/wordpress/wp-content, the folders will be copied across to /var/www/html/wp-content/ at startup?
(Some posts I've looked through that don't work, as this seems to be particular to Wordpress, and not Dockerfile COPY on its own:)
Dockerfile copy keep subdirectory structure
Docker is not copying subdirectory into Container
How to copy folders to docker image from Dockerfile?
https://www.serverlab.ca/tutorials/containers/docker/how-to-host-your-wordpress-site-with-docker/
Wordpress docker copy theme into exposed folder

Answer 1

Today I ran into the same problem. I wanted to add theme when building the image by using COPY. However, it did not work. This was because I already set my wp-content folder as a volume. It seems you cannot COPY into a volume.
The discussion in the following link helped me realise this:
https://github.com/docker-library/wordpress/issues/146
Below I have added my WordPres Dockerfile and docker-compose file. After commenting out the volume everything worked as expected.
I sure hope you do not need it anymore after two years, haha.
Reference: https://docs.docker.com/samples/wordpress/
Dockerfile
FROM wordpress:latest
WORKDIR /var/www/html
COPY ./wp-content/ ./wp-content/
RUN chmod -R 755 ./wp-content/
docker-compose.yml
version: "3"
services:
db:
build:
context: .
dockerfile: ./compose/local/db/Dockerfile
image: new_db_image_name
container_name: new_db_image_name
command: '--default-authentication-plugin=mysql_native_password'
volumes:
- db_data:/var/lib/mysql
restart: always
environment:
- MYSQL_ROOT_PASSWORD=somewordpress
- MYSQL_DATABASE=wordpress
- MYSQL_USER=wordpress
- MYSQL_PASSWORD=wordpress
expose:
- 3306
- 33060
wordpress:
build:
context: .
dockerfile: ./compose/local/wordpress/Dockerfile
image: new_wordpress_image_name
container_name: new_wordpress_image_name
# volumes:
# - wp-content:/var/www/html/wp-content
ports:
- 80:80
restart: always
environment:
- WORDPRESS_DB_HOST=db
- WORDPRESS_DB_USER=wordpress
- WORDPRESS_DB_PASSWORD=wordpress
- WORDPRESS_DB_NAME=wordpress
volumes:
db_data:
# wp-content: