Docker Image: PHP with MySQLi


Hypertext Preprocessor (PHP) has been a staple in web development for years. PHP has been part of my web development since the beginning. Originally I ran the service embedded in Apache but when migrating to Docker it was time for a change. Instead of being coupled with Apache, it was time to make the switch to FastCGI Process Manager (FPM) and a separate NGINX container. After a few days experimentation, the PHP docker image with the MySQLi extension was born.

Since most people like to build the images themselves, I have the full script to build the image available on gitlab or one might take the easy way out and pull my image: djpic/php.

What is the Image?

This Docker image is sourced from the Official Docker PHP FPM Alpine image. To make sure the image is stable for production, the most recent PHP version is not included. The current versions are 8.0 and 8.1.

The image includes Composer along with the MySQLi and memcached extensions. Optional are the browscap files. The browscap files are updated every time a new image is built even if the FPM version has not been updated.

How to use the image

The image is designed to be used with my NGINX image (djpic/nginx) but can be used with any FPM web server. All PHP files should be copied/mounted into the same location as the corresponding web server. For example, if using the default NGINX settings, /usr/share/nginx/html.

The memcached extension is included as a method to cache database responses and/or to store temporary data. Like MySQLi, memcached is an extension and requires a memcached container.

As a bonus Composer is installed to manage application dependencies. This gives the option of building an image with common SDKs such as AWS S3, Stripe, and mailgun. I recommend to install these dependencies in the root of the docker image making the include path within PHP applications: /vendor/autoload.php.

Example of Dockerfile installing AWS S3 SDK:

FROM djpic/php:8.1.12-mysqli

# Install mailgun and required packages
RUN cd /composer/ \
  && composer require aws/aws-sdk.php

Image Tags

The image tags are organized by version and what is included in the image. There are 4 different tag variants for each published version: mysqli, mysqli-browscap, mysqli-lite_php_browscap, and mysqli-full_php_browscap. For the browscap variants, the updated php.ini file to use the browscap file is included.

This base variant includes MySQLi extension and memcached extension along with Composer. This variant is the best for the majority of applications.
The first variant that includes the browscap file. Includes everything in the mysqli variant with the PHP specific browscap file.
Includes the lite, smaller, browscap file.
For those that want the full browscap file. This is the largest browscap file available making this variant the largest. Only use this variant if need the full featured browscap file

Build the Image

All docker builds start with a Dockerfile. The primary Dockerfile for this image is where the base PHP image is pulled from the Official Docker PHP alpine image. When changing the base PHP image of all variants for the image, update the FROM in this Dockerfile. The MySQLi and memcached extensions are installed into the image a this stage along with Composer.

ARG php_version
FROM php:${php_version}-fpm-alpine

# Install MySQLi
RUN docker-php-ext-install mysqli

# Install Memcached Extensions
ENV MEMCACHED_DEPS zlib-dev libmemcached-dev cyrus-sasl-dev
RUN apk add --no-cache --update libmemcached-libs zlib
RUN set -xe \
    && apk add --no-cache --update --virtual .phpize-deps $PHPIZE_DEPS \
    && apk add --no-cache --update --virtual .memcached-deps $MEMCACHED_DEPS \
    && pecl install memcached \
    && echo "" > /usr/local/etc/php/conf.d/20_memcached.ini \
    && rm -rf /usr/share/php7 \
    && rm -rf /tmp/* \
    && apk del .memcached-deps .phpize-deps

# Install PHP Composer
RUN mkdir /composer/ \
    && cd /composer/ \
    && php -r "copy('', 'composer-setup.php');" \
    && php composer-setup.php \
    && php -r "unlink('composer-setup.php');" \
    && mv composer.phar /usr/local/bin/composer

The next Dockerfile is for the browscap versions. The browscap Dockerfile uses the previous MySQLi image variant as a base. This Dockerfile copies in the browscap file and the updated php.ini file. The same Dockerfile is used for each browscap variant.

ARG php_version
FROM djpic/php:${php_version}-mysqli

# Copy PHP.ini file with browscap defined
COPY php.ini /usr/local/etc/php/php.ini
# Copy the browscap.ini file
COPY browscap.ini /usr/local/etc/php/browscap.ini


Below is the updated line in the php.ini file.

browscap = /usr/local/etc/php/browscap.ini

Finally comes the glue that brings everything together: Following removing any old images, the shell script begins to build the MySQLi image first. From there, the script continues on to the browscap variants. The script pulls the latest browscap file, runs the browscap Dockerfile, then removes the browscap file that was pulled. This is repeated 2 more times for each browscap variant.

Once all image variants are completed, they are pushed to the DockerHub then removed from the build machine.

# Declare array with the two versions to compiled.
php_versions=(8.0.25 8.1.12)

for php_version in "${php_versions[@]}"
    # Build apache image with mysqli and memcached extension
    cd MySQLi
    docker build --build-arg php_version=$php_version --tag djpic/php:$php_version-mysqli .

    # Build image with browscap file
    cd browscap
    wget -O browscap.ini
    docker build --build-arg php_version=$php_version --tag djpic/php:$php_version-mysqli-browscap .
    rm browscap.ini
    wget -O browscap.ini
    docker build --build-arg php_version=$php_version --tag djpic/php:$php_version-mysqli-full_php_browscap .
    rm browscap.ini
    wget -O browscap.ini
    docker build --build-arg php_version=$php_version --tag djpic/php:$php_version-mysqli-lite_php_browscap .
    rm browscap.ini

    # Docker Push Image
    docker push djpic/php:$php_version-mysqli
    docker push djpic/php:$php_version-mysqli-browscap
    docker push djpic/php:$php_version-mysqli-full_php_browscap
    docker push djpic/php:$php_version-mysqli-lite_php_browscap

    cd ../../

Sample docker-compose file

Since both my djpic/php and djpic/nginx images are designed to work together, I provided an example of a docker-compose file using both images. The two containers use the back end network to communicate. I do use a custom image of Traefik, so this docker-compose file does include djpic/traefik labels.

version: "3.2"
    image: djpic/nginx:phpfpm
      - FrontEnd
      - BackEnd
      - php
      - ./application/:/app
      - "traefik.enable=true"
      - "traefik.http.routers.djpicdemo-web.rule=Host(``)"
      - "traefik.http.routers.djpicdemo-web.entrypoints=web"
      - "traefik.http.routers.djpicdemo-web.middlewares=https-redirect@file"
      - "traefik.http.routers.djpicdemo-tls.rule=Host(``)"
      - "traefik.http.routers.djpicdemo-tls.entrypoints=websecure"
      - "traefik.http.routers.djpicdemo-tls.tls.certresolver=letsencrypt"
      - "traefik.http.routers.djpicdemo-tls.middlewares=secure-headers@file, compress-content@file"
    restart: always

    image: djpic/php:mysqli
      - BackEnd
      - ./application/:/app

    image: library/memcached:alpine
      - BackEnd
    command: ["-m", "64m"]
    restart: always

    external: true


Fully built images are available and free to use on my Docker Hub. In addition, the source files listed here are available along with my other public docker images on gitlab. Feel free to download, modify, and reuse. Just remember to update the image names.

This image has proved invaluable to my development. I use this image for every project PHP is needed. More variants may be added to this image as the need arises. When that happens, this article will be updated.

Follow my twitter account @djpic_llc for updates to the this article and other announcements. I also welcome all constructive input. If anything is incorrect or needs further explanation, please do contact me.

The contents of this article are of my opinion and based on my experience. Before applying any of the concepts or suggestions in this article, complete your own independent research and testing. By reading this article, the reader agrees that Dale M. Picou, Jr. shall not be held liable for any negative impact when applying these tutorials, concepts, and/or suggestions.