SQLSTATE[HY000] [2002] No such file or directory

SQLSTATE[HY000] [2002] Connection refused

$ ls -l /var/run/mysqld/mysqld.sock
$ srwxrwxrwx 1 mysql mysql 0 nov 27 08:31 /var/run/mysqld/mysqld.sock

; Default socket name for local MySQL connects.  If empty, uses the built-in
; MySQL defaults.
; http://php.net/pdo_mysql.default-socket
pdo_mysql.default_socket=/var/run/mysqld/mysqld.sock

DB_CONNECTION=mysql
DB_HOST=localhost
DB_PORT=3306
DB_DATABASE=test
DB_USERNAME=developer
DB_PASSWORD=123456

'mysql' => [
        'driver' => 'mysql',
        'host' => env('DB_HOST', 'localhost'),
        'port' => env('DB_PORT', '3306'),
        'database' => env('DB_DATABASE', 'forge'),
        'username' => env('DB_USERNAME', 'forge'),
        'password' => env('DB_PASSWORD', ''),
        'charset' => 'utf8',
        'collation' => 'utf8_unicode_ci',
        'prefix' => '',
        'strict' => false,
        'engine' => null,
    ],

version: "3.3"
services:
   api_test:
      build: .
      ports:
         - "8181:8181"
      env_file:
         - ./.env
      environment:
         - PORT:8181

FROM php:7.1.5-apache

RUN apt-get update -y && apt-get install -y openssl zip unzip git
RUN curl -sS https://getcomposer.org/installer | php -- --install-dir=/usr/local/bin --filename=composer
RUN docker-php-ext-install pdo pdo_mysql mbstring
WORKDIR /api_test
COPY . /api_test
RUN composer install
RUN a2enmod rewrite
CMD php artisan serve --host=0.0.0.0 --port=8181
EXPOSE 8181