Convert simple Dockerfile to docker-compose - php

Question

I have a simple Dockerfile for php:7.2-fpm that is being referenced by my docker-compose.yml configuration. I want to get rid of the Dockerfile which is located at php/Dockerfile and integrate the commands to my docker-compose-yml file.
Here is my php/Dockerfile:
FROM php:7.2-fpm
RUN docker-php-ext-install mysqli
And here is my docker-compose.yml which brings up php-fpm, nginx, letencrypt certbot, mysql, and phpmyadmin:
version: '3'
services:
php:
container_name: dev_php
build:
context: ./php
ports:
- 9000:9000
volumes:
- ./website:/website
- ./php/www.conf:/usr/local/etc/php-fpm.d/www.conf
environment:
MYSQL_USER: ${MYSQL_USER}
MYSQL_PASSWORD: ${MYSQL_PASSWORD}
nginx:
container_name: dev_nginx
image: nginx:1.13.8
ports:
- 80:80
- 443:443
volumes:
- ./website:/website
- ./nginx/default.conf:/etc/nginx/conf.d/default.conf
- ./certbot/conf:/etc/letsencrypt
- ./certbot/www:/var/www/certbot
depends_on:
- php
- mysql
command: "/bin/sh -c 'while :; do sleep 6h & wait $${!}; nginx -s reload; done & nginx -g \"daemon off;\"'"
certbot:
container_name: dev_certbot
image: certbot/certbot
volumes:
- ./certbot/conf:/etc/letsencrypt
- ./certbot/www:/var/www/certbot
entrypoint: "/bin/sh -c 'trap exit TERM; while :; do certbot renew; sleep 12h & wait $${!}; done;'"
mysql:
container_name: dev_mysql
image: mysql:5.7
ports:
- 3306:3306
environment:
MYSQL_ROOT_PASSWORD: ${MYSQL_ROOT_PASSWORD}
MYSQL_DATABASE: ${MYSQL_DATABASE}
MYSQL_USER: ${MYSQL_USER}
MYSQL_PASSWORD: ${MYSQL_PASSWORD}
volumes:
- ./mysql:/docker-entrypoint-initdb.d
phpmyadmin:
container_name: dev_pma
image: phpmyadmin/phpmyadmin
links:
- mysql
depends_on:
- mysql
environment:
PMA_HOST: mysql
PMA_PORT: 3306
PMA_ARBITRARY: 1
restart: always
ports:
- 8183:80
Since my php/Dockerfile is relatively simple, I thought I could do something like this:
php:
container_name: dev_php
image: php:7.2-fpm
ports:
- 9000:9000
volumes:
- ./website:/website
- ./php/www.conf:/usr/local/etc/php-fpm.d/www.conf
environment:
MYSQL_USER: ${MYSQL_USER}
MYSQL_PASSWORD: ${MYSQL_PASSWORD}
command: bash -c "docker-php-ext-install mysqli"
But this does not work. When I bring my project up using docker-compose up I can see dev_php (the name of the PHP container) perform a bunch of tasks that I do not ordinarily see, it then proceeds to install mysqli but then quits immediately after with exit code 0.
Thoughts?

Answer 1

Your original Dockerfile does much more than just installing the mysqli extension.
It has the entrypoint as shown in the source code here
It also has the command as shown here
These entrypoint and command are what will start the container and keep it running
Now back to your modification:
I can see dev_php (the name of the PHP container) perform a bunch of tasks that I do not ordinarily see
This is the output of docker-php-ext-install mysqli. You did not see it before is because it was done when building the docker image.
quits immediately after with exit code 0
This is expected because the command has finished processing and there is nothing else for it to do.
In order to keep the container running, you will have to manually add in the original entrypoint and command. Something like this:
php:
container_name: dev_php
image: php:7.2-fpm
ports:
- 9000:9000
volumes:
- ./website:/website
- ./php/www.conf:/usr/local/etc/php-fpm.d/www.conf
environment:
MYSQL_USER: ${MYSQL_USER}
MYSQL_PASSWORD: ${MYSQL_PASSWORD}
entrypoint:
- bash
- -c
command:
- |
docker-php-ext-install mysqli; \
docker-php-entrypoint php-fpm
I have not tested to confirm that the syntax is 100% correct but you should get the idea. The important bit is docker-php-entrypoint php-fpm
My recommendation is to just stick to using Dockerfile in this case.
A good side effect is that Docker will cache the build layers so you do not need to wait for the installing process of mysqli every time you want to start the containers.
You may consider enabling the extension too