61SQLSTATE[HY000] [2002] Connection refused in Docker Container PHP/Apache - php

Question

I have recently switched from XAMPP to Docker for PHP Development and have managed to get my project running. The project was running fine on XAMPP, but for whatever reason the database kept on getting corrupt, hence the switch to Docker. This question has probably been asked before, but i have not been able to find an answer for it so far.
I have a login page, from where i submit the data to a php script, which makes a connection with the database and in that part, it runs into an exception:
61SQLSTATE[HY000] [2002] Connection refused61SQLSTATE[HY000] [2002] Connection refused
Warning: Cannot modify header information - headers already sent by (output started at /var/www/inc/cDBConnection.inc.php:61)
I have a docker-compose.yml file:
version: "3.2"
services:
php:
build: './php/'
networks:
- backend
volumes:
- ./project/:/var/www/html/
- ./inc/:/var/www/inc/
apache:
build: './apache/'
depends_on:
- php
- mysql
networks:
- frontend
- backend
ports:
- "8080:80"
volumes:
- ./project/:/var/www/html/
mysql:
image: mysql:5.6.40
ports:
- "3306:3306"
volumes:
- ./db:/var/lib/mysql
networks:
- backend
environment:
- MYSQL_ROOT_PASSWORD=password
networks:
frontend:
backend:
A Dockerfile in the apache folder:
FROM httpd:2.4.33-alpine
RUN apk update; \
apk upgrade;
# Copy apache vhost file to proxy php requests to php-fpm container
COPY apache.conf /usr/local/apache2/conf/apache.conf
RUN echo "Include /usr/local/apache2/conf/apache.conf" \
>> /usr/local/apache2/conf/httpd.conf
A Dockerfile in the php folder:
FROM php:7.2.7-fpm-alpine3.7
RUN apk update; \
apk upgrade;
RUN docker-php-ext-install pdo pdo_mysql mysqli
the DBConnection.php:
$this->_config = $databaseConfig;
$dsn = "" .
$this->_config['driver'] .
":host=" . $this->_config['host'] .
";dbname=" . $this->_config['dbname'];
try {
$this->dbc = new PDO( $dsn, $this->_config[ 'username' ], $this->_config[ 'password' ] );
} catch( PDOException $e ) {
echo __LINE__.$e->getMessage(); // here i run into this exception
}
I assume i'm missing some extension in the dockerfile, but if i log in through a mysql query browser, i am able to log in as root user. For the project i have another user, which i created with:
CREATE USER 'sec_user'#'localhost' IDENTIFIED BY 'password';
GRANT SELECT, INSERT, UPDATE ON `project`.* TO 'sec_user'#'localhost';
when i tried to log in with this user, i got an error "access denied", so i followed checked with:
SELECT user, host FROM mysql.user;
UPDATE mysql.user SET host='%' WHERE user='sec_user';
FLUSH PRIVILEGES
and the login worked with the query browser but on the frontend I'm unable to get in. Does anyone know what the problem here is?

Answer 1

I found the solution to this issue. The credentials are passed on through the environment variables and connecting to localhost or 127.0.0.1 will not work.
the credentials should be in the dockerfile:
environment:
- MYSQL_ROOT_PASSWORD=password
- MYSQL_DATABASE=test_db
- MYSQL_USER=sec_user
- MYSQL_PASSWORD=password
these are then accessed in the DBConnection.php like this:
'host' => "mysql", //this is from the dockerfile, docker does the mapping for you
'port' => '3306',
'dbname' => $_ENV["MYSQL_DATABASE"],
'username' => $_ENV["MYSQL_USER"],
'password' => $_ENV["MYSQL_PASSWORD"]
and succesfully connected!