docker-compose.yml

version: "3.1"

services:
  webserver-nginx:
    image: nginx:latest
    ports:
      - "8080:80"
    volumes:
      - ./code:/var/www/html
      - ./conf/nginx.conf:/etc/nginx/conf.d/default.conf
    links:
      - webserver-php

  webserver-php:
    build: ./services/php/
    image: webserver-php
    volumes:
      - ./code:/var/www/html
    ports:
      - 9000

docker-entrypoint

#!/bin/sh

#services/php/docker-entrypoint

EXPECTED_SIGNATURE="$(wget -q -O - https://composer.github.io/installer.sig)"
php -r "copy('https://getcomposer.org/installer', 'composer-setup.php');"
ACTUAL_SIGNATURE="$(php -r "echo hash_file('sha384', 'composer-setup.php');")"

if [ "$EXPECTED_SIGNATURE" != "$ACTUAL_SIGNATURE" ]
then
    >&2 echo 'ERROR: Invalid installer signature'
    rm composer-setup.php
    exit 1
fi

php composer-setup.php --quiet
RESULT=$?
rm composer-setup.php

php composer.phar install

Dockerfile

#services/php/Dockerfile

FROM php:7.3-fpm

WORKDIR /var/www/html

ENV COMPOSER_ALLOW_SUPERUSER=1
ENV COMPOSER_NO_INTERACTION=1
ENV COMPOSER_HOME=/usr/local/share/composer

RUN apt-get update && \
    apt-get install -y --no-install-recommends wget git zip unzip

COPY ./docker-entrypoint /

RUN ["chmod", "+x", "/docker-entrypoint"]

ENTRYPOINT [ "/docker-entrypoint" ]

CMD ["sh", "-c", "/docker-entrypoint"]

nginx.conf

#conf/nginx.conf

server {
    index index.php index.html;
    server_name php-docker.local;
    error_log /var/log/nginx/error.log;
    access_log /var/log/nginx/access.log;
    root /var/www/html;

    location ~ \.php$ {
        try_files $uri =404;
        fastcgi_split_path_info ^(.+\.php)(/.+)$;
        fastcgi_pass webserver-php:9000;
        fastcgi_index public/index.php;
        include fastcgi_params;
        fastcgi_param SCRIPT_FILENAME $document_root$fastcgi_script_name;
        fastcgi_param PATH_INFO $fastcgi_path_info;
    }
}