可以从docker容器外部连接到数据库，但不能从内部（在laravel中）连接到数据库

Question

由于投票减少，我重构了这个问题。

它就像这样简单：

外码头集装箱：

➜  backoffice git:(master) ✗ php artisan tinker
Psy Shell v0.9.9 (PHP 7.2.15 — cli) by Justin Hileman
>>> $ur = app(MDiPaoloRepositoriesUserRepository::class)
=> AppInfrastructureRepositoriesDoctrineUserDoctrineRepository {#3159}
>>> $u = new MDiPaoloEntitiesUser
=> MDiPaoloEntitiesUser {#3295}
>>> $u->setEmail('one_email@gmail.com')
=> MDiPaoloEntitiesUser {#3295}
>>> $u->setPassword(password_hash('1234', PASSWORD_BCRYPT))
=> null
>>> $ur->save($u)
=> null
>>>

在docker容器内：

➜  backoffice git:(master) ✗ docker exec -it backoffice_web_1 bash
root@042969f0229c:/var/www/html# php artisan tinker
Psy Shell v0.9.9 (PHP 7.2.17 — cli) by Justin Hileman
>>> $ur = app(MDiPaoloRepositoriesUserRepository::class)
Doctrine/DBAL/Exception/ConnectionException with message 'An exception occurred in driver: SQLSTATE[HY000] [2002] Connection refused'
>>>

我觉得它与docker系统有关，比如两个容器之间的通信或我是如何构建它们的。

这是我的Dockerfile。

FROM php:7.2-apache

RUN docker-php-ext-install pdo_mysql && docker-php-ext-enable pdo_mysql
RUN apt-get update && apt-get install nano && mv "$PHP_INI_DIR/php.ini-development" "$PHP_INI_DIR/php.ini"

RUN a2enmod rewrite
RUN service apache2 restart

ENV APACHE_DOCUMENT_ROOT=/var/www/html/public
RUN sed -ri -e 's!/var/www/html!${APACHE_DOCUMENT_ROOT}!g' /etc/apache2/sites-available/*.conf
RUN sed -ri -e 's!/var/www/!${APACHE_DOCUMENT_ROOT}!g' /etc/apache2/apache2.conf /etc/apache2/conf-available/*.conf

docker-compose文件：

version: '3.1'

services:
    web:
        build: .
        ports:
            - "8080:80"
        links:
            - mysql
        depends_on:
            - mysql
        volumes:
            - ./:/var/www/html
    mysql:
        image: mysql:5.7.25
        ports:
            - "3306:3306"
        environment:
            MYSQL_ROOT_PASSWORD: backoffice