As pointed out before, the problem was that the files were not visible by the fpm container. However to share data among containers the recommended pattern is using data-only containers (as explained in this article).
Long story short: create a container that just holds your data, share it with a volume, and link this volume in your apps with volumes_from.
Using compose (1.6.2 in my machine), the docker-compose.yml file would read:
version: "2"
services:
nginx:
build:
context: .
dockerfile: nginx/Dockerfile
ports:
- "80:80"
links:
- fpm
volumes_from:
- data
fpm:
image: php:fpm
volumes_from:
- data
data:
build:
context: .
dockerfile: data/Dockerfile
volumes:
- /var/www/html
Note that data publishes a volume that is linked to the nginx and fpm services. Then the Dockerfile for the data service, that contains your source code:
FROM busybox
# content
ADD path/to/source /var/www/html
And the Dockerfile for nginx, that just replaces the default config:
FROM nginx
# config
ADD config/default.conf /etc/nginx/conf.d
For the sake of completion, here's the config file required for the example to work:
server {
listen 0.0.0.0:80;
root /var/www/html;
location / {
index index.php index.html;
}
location ~ \.php$ {
include fastcgi_params;
fastcgi_pass fpm:9000;
fastcgi_index index.php;
fastcgi_param SCRIPT_FILENAME $document_root/$fastcgi_script_name;
}
}
which just tells nginx to use the shared volume as document root, and sets the right config for nginx to be able to communicate with the fpm container (i.e.: the right HOST:PORT, which is fpm:9000 thanks to the hostnames defined by compose, and the SCRIPT_FILENAME).