PHP application can't connect to MariaDB using Docker Compose - php

Question

My application is set up using Docker Compose. My docker-compose.yml contents;
version: "3.1"
services:
nginx-proxy:
image: jwilder/nginx-proxy
container_name: nginx-proxy
ports:
- "80:80"
- "443:443"
volumes:
- /var/run/docker.sock:/tmp/docker.sock:ro
db:
image: mariadb:10.4
restart: always
ports:
- "3307:3306"
volumes:
- ./mysql:/var/lib/mysql
container_name: mariadb
environment:
- MYSQL_DATABASE=dbname
- MYSQL_PASSWORD=dbpass
- MYSQL_RANDOM_ROOT_PASSWORD=yes
- MYSQL_USER=dbuser
phpapp:
depends_on:
- nginx-proxy
- db
image: myhub/myrepo
restart: always
container_name: phpapp
expose:
- 80
- 443
environment:
- APP_ENV=prod
- APP_SECRET="secret"
- CORS_ALLOW_ORIGIN="^.*?$$"
- DATABASE_URL="mysql://dbuser:dbpass#db/dbname"
- VIRTUAL_HOST=phpapp.com
networks:
default:
external:
name: nginx-proxy
However, when I try to connect to the database in the application I get an error message; SQLSTATE[HY000] [2002] No such file or directory.
I can, however, connect on port 3307 on my localhost with the correct username and password. Also, when I access the container using docker exec -ti phpapp /bin/bash and run env I get all the environment variables listed and they are correct.
When I execute docker network inspect nginx-proxy I get;
[
{
"Name": "nginx-proxy",
"Id": "2529933d7e38cfba34e0e876e43a96fc4c8d7321c1e89048319ba804b00e1026",
"Created": "2018-12-12T05:04:01.9044879Z",
"Scope": "local",
"Driver": "bridge",
"EnableIPv6": false,
"IPAM": {
"Driver": "default",
"Options": {},
"Config": [
{
"Subnet": "172.18.0.0/16",
"Gateway": "172.18.0.1"
}
]
},
"Internal": false,
"Attachable": false,
"Ingress": false,
"ConfigFrom": {
"Network": ""
},
"ConfigOnly": false,
"Containers": {},
"Options": {},
"Labels": {}
}
]
The containers array is empty, however a default (external) network is set in the docker-compose.yml.

Answer 1

Welcome to stackoverflow :)
I think maybe it is not working for db container not linked from phpapp container. Can you try like this?
version: "3.1"
services:
nginx-proxy:
image: jwilder/nginx-proxy
container_name: nginx-proxy
ports:
- "80:80"
- "443:443"
volumes:
- /var/run/docker.sock:/tmp/docker.sock:ro
db:
image: mariadb:10.4
restart: always
ports:
- "3307:3306"
volumes:
- ./mysql:/var/lib/mysql
container_name: mariadb
environment:
- MYSQL_DATABASE=dbname
- MYSQL_PASSWORD=dbpass
- MYSQL_RANDOM_ROOT_PASSWORD=yes
- MYSQL_USER=dbuser
phpapp:
depends_on:
- nginx-proxy
links:
- db
image: myhub/myrepo
restart: always
container_name: phpapp
expose:
- 80
- 443
environment:
- APP_ENV=prod
- APP_SECRET="secret"
- CORS_ALLOW_ORIGIN="^.*?$$"
- DATABASE_URL="mysql://dbuser:dbpass#db/dbname"
- VIRTUAL_HOST=phpapp.com
networks:
default:
external:
name: nginx-proxy
I moved db from depends_on to links. You must use db for hostname in database connection now.
I hope i could help.

Answer 2

Well, I've found the solution to this problem. However, it's not the one I expected. The database URL is defined as:
DATABASE_URL="mysql://dbuser:dbpass#db/dbname"
It should be without quotes, like this:
DATABASE_URL=mysql://dbuser:dbpass#db/dbname
Now everything seems to work, does anyone know when and why you can and can't use quotes?