Docker Volume Persistence - docker

Question

I am trying to learn Docker. I have installed Docker Desktop on my Windows10 Pro computer.
I started with getting a PHP, MySQL website up and running using Docker.
My docker-compose.yml looks like
version: "3.8"
services:
www:
build: .
ports:
- "80:80"
volumes:
- ./www:/var/www/html
links:
- db
networks:
- default
db:
image: mysql:8.0
ports:
- "3306:3306"
command: --default-authentication-plugin=mysql_native_password
environment:
MYSQL_DATABASE: myDb
MYSQL_USER: user
MYSQL_PASSWORD: test
MYSQL_ROOT_PASSWORD: test
volumes:
- ./dump:/docker-entrypoint-initdb.d
- ./conf:/etc/mysql/conf.d
- persistent:/var/lib/mysql
networks:
- default
phpmyadmin:
image: phpmyadmin/phpmyadmin
links:
- db:db
ports:
- 8000:80
environment:
MYSQL_USER: user
MYSQL_PASSWORD: test
MYSQL_ROOT_PASSWORD: test
volumes:
persistent:
and the DockerFile looks like
FROM php:7.3-apache
RUN docker-php-ext-install mysqli
RUN apt-get update \
&& apt-get install -y libzip-dev \
&& apt-get install -y wget \
&& apt-get install -y zlib1g-dev \
&& rm -rf /var/lib/apt/lists/* \
&& docker-php-ext-install zip
I have a www folder with an index.php.
When I run
docker-compose up -d
I have the PHP, mySQL site up and running correctly and I can access the index.php with expected results.
So far so good.
Now, I want to change the Dockerfile to setup a php forum website (phpbb) - so I have updated my Dockerfile as follows:
FROM php:7.3-apache
RUN docker-php-ext-install mysqli
RUN apt-get update \
&& apt-get install -y libzip-dev \
&& apt-get install -y wget \
&& apt-get install -y zlib1g-dev \
&& rm -rf /var/lib/apt/lists/* \
&& docker-php-ext-install zip
WORKDIR /var/www/html
RUN wget https://download.phpbb.com/pub/release/3.3/3.3.0/phpBB-3.3.0.tar.bz2 \
&& tar -xvjf phpBB-3.3.0.tar.bz2
&& ls -l
When I run
docker-compose build --no-cache
I can see the expected results - i.e, the "ls" command shows all the expected phpBB files in /var/www/html
However, when I run
docker-compose up -d
My container only has the index.php in the /var/www/html (the index.php from the www folder). None of the phpBB files are there.
What am I doing wrong?

Answer 1

The files are there but you are hiding them by your bind mount.
You are bind mounting ./www into the same directory (/var/www/html) which will hide its contents.
here:
www:
...
volumes:
- ./www:/var/www/html
When you are building the image, you correctly see the files but once you run docker-compose the bind mount is created and it hides those files.