从 .env 或 dockerFile/docker-compose.yml 获取环境变量，到 config,php 以连接到 mysql 数据库

Question

Instead of hardcoding the db_username and password, I want to define a env variable in docker. I am new to Docker, so some stuff I still need to learn more about.

Another question i want to ask is, if someone else want to run my container, like clone from github, they will have to set themselves the env variables to connect to db right? Create a .env and stuff like that..

config.php

<?php

define('DB_SERVER', getenv('DB_SERVER'));
define('DB_USERNAME', getenv('DB_USERNAME'));
define('DB_PASSWORD', getenv('DB_PASSWORD')); 
define('DB_NAME', getenv('DB_NAME'));

$link = mysqli_connect(DB_SERVER, DB_USERNAME, DB_PASSWORD, DB_NAME);

if ($link === false) {
    die ("ERROR: Could not connect. " . mysqli_connect_error());
}

?>

.env

DB_SERVER=db
DB_USERNAME=dbuser
DB_PASSWORD=dbpassword
DB_NAME=company

docker-compose.yml

db:
  build: ./backend
  restart: always
  ports:
    - "3306:3306"
  volumes:
    - /var/lib/mysql
  environment:
    - MYSQL_ROOT_PASSWORD=dbpassword
php:
  build: ./frontend
  ports:
    - "80:80"
  volumes: 
    - ./frontend:/var/www/html
  environment:
    - DB_SERVER=${DB_SERVER}
    - DB_USERNAME=${DB_USERNAME}
    - DB_PASSWORD=${DB_PASSWORD}
    - DB_NAME=${DB_NAME}
  env_file: ./.env
  links:
    - db

Dockerfile in ./frontend

FROM php:7.2-apache

RUN docker-php-ext-install mysqli

WORKDIR /var/www/html

COPY . /var/www/html/

Dockerfile in ./backend

FROM mysql:5.7

COPY ./demo.sql /docker-entrypoint-initdb.d

I don't know if the way it is right now, is getting the variables form the env file, when i run with the docker-compose up, and go to 192.168.99.100, my application is working, but i get

In the .yml file, i think i don't need the environment variables set, but i was testing if i could get that variables, directly put into the config.php, for someone who will run my container, only need to run "docker-compose up" and not set everything.

Warning: mysqli_connect(): (HY000/1045): Access denied for user 'dbuser'@'172.17.0.3' (using password: YES) in /var/www/html/config.php on line 8

I don't know how to solve that. So basically, it's two questions, why this error, and if I'm doing the environment variables right.

Answer 1

我设法让它工作，我真的不知道我改变了什么，但基本上我删除了environment:从php容器，并移动到db容器，使用来自 dockerhub 的 mysql 图像环境变量。

Answer 2

I have solved this problem You need to add variable PHP_FPM_CLEAR_ENV=no

 environment: - PHP_FPM_CLEAR_ENV=no

After that everything is ok!