Connecting to MySQL with Ecto in Docker - mysql

Question

I am in the process of Dockerizing my project, and the following is my docker-compose.yml:
version: '3.8'
services:
server:
image: server
environment:
DB_HOST: 0.0.0.0
DB_DATABASE: dev
DB_PORT: 3306
DB_USER: dev
DB_PASSWORD: dev
ports:
- "4000:4000"
restart: on-failure
depends_on:
database:
condition: service_started
database:
image: mysql:latest
command: --default-authentication-plugin=mysql_native_password
ports:
- "3306:3306"
environment:
MYSQL_ROOT_PASSWORD: root
MYSQL_USER: dev
MYSQL_PASSWORD: dev
MYSQL_DATABASE: dev
volumes:
- mysql_data:/var/lib/mysql
volumes:
mysql_data:
and the Dockerfile for server:
FROM elixir:latest
EXPOSE 4000
RUN mkdir /server
COPY . /server
WORKDIR /server
RUN mix local.rebar --force
RUN mix local.hex --force
RUN mix deps.get
RUN mix do compile
CMD [ "sh", "/server/entry.sh" ]
where entry.sh is:
# Exit on failure
set -e
mix ecto.create
mix ecto.migrate
mix run priv/repo/seeds.exs
exec mix phx.server
When I run this using docker compose up, I get an error that Phoenix can't connect to the MySQL database. I have tried using hosts 0.0.0.0 and localhost, however both don't work.
This is the corresponding section of my config/dev.exs:
config :app, App.Repo
username: System.get_env("DB_USER"),
password: System.get_env("DB_PASSWORD"),
hostname: System.get_env("DB_HOST"),
database: System.get_env("DB_DATABASE"),
port: 3306,
stacktrace: true,
pool_size: 10
The following is the exact error message I get:
server-1 | 11:23:07.417 [error] GenServer #PID<0.272.0> terminating
server-1 | ** (DBConnection.ConnectionError) (0.0.0.0:3306) connection refused - :econnrefused
server-1 | (db_connection 2.4.3) lib/db_connection/connection.ex:100: DBConnection.Connection.connect/2
server-1 | (connection 1.1.0) lib/connection.ex:622: Connection.enter_connect/5
server-1 | (stdlib 4.2) proc_lib.erl:240: :proc_lib.init_p_do_apply/3
server-1 | Last message: nil
server-1 | State: MyXQL.Connection
server-1 |
server-1 | 11:23:07.430 [error] GenServer #PID<0.278.0> terminating
server-1 | ** (DBConnection.ConnectionError) (0.0.0.0:3306) connection refused - :econnrefused
server-1 | (db_connection 2.4.3) lib/db_connection/connection.ex:100: DBConnection.Connection.connect/2
server-1 | (connection 1.1.0) lib/connection.ex:622: Connection.enter_connect/5
server-1 | (stdlib 4.2) proc_lib.erl:240: :proc_lib.init_p_do_apply/3
server-1 | Last message: nil
server-1 | State: MyXQL.Connection
server-1 | ** (Mix) The database for App.Repo couldn't be created: %RuntimeError{message: "killed"}
server-1 exited with code 1