Running app through docker-compose doesn't work with default network

Working on Ubuntu 18.04, when I run the app through docker-compose I get nothing in the browser.

Running the two containers from the command line works fine, with the commands below:

~/dev/docker/app$ docker run -d     \
                                  --network todo-app \
                                  --network-alias mysql  \
                                  -v todo-mysql-data:/var/lib/mysql   \
                                  -e MYSQL_ROOT_PASSWORD=secret    \
                                  -e MYSQL_DATABASE=todos    \
                                  mysql:5.7

~/dev/docker/app$ docker run -dp 3000:3000   \
                                  -w /app -v ${PWD}:/app   \
                                  --network todo-app   \
                                  -e MYSQL_HOST=mysql   \
                                  -e MYSQL_USER=root   \
                                 -e MYSQL_PASSWORD=secret   \
                                 -e MYSQL_DB=todos   \
                                 node:12-alpine \
                                 sh -c "yarn install && yarn run dev"

But when I run it using docker-compose, it fails, without any errors (other than the working version). The docker-compose.yml is according to the tutorial:

version: "3.7"

services:
  app:
    image: node:12-alpine
    command: sh -c "yarn install && yarn run dev"
    ports:
      - 3000:3000
    working_dir: /app
    volumes:
      - ./:/app
    environment:
      MYSQL_HOST: mysql
      MYSQL_USER: root
      MYSQL_PASSWORD: secret
      MYSQL_DB: todos

  mysql:
    image: mysql:5.7
    volumes:
      - todo-mysql-data:/var/lib/mysql
    environment: 
      MYSQL_ROOT_PASSWORD: secret
      MYSQL_DATABASE: todos

volumes:
  todo-mysql-data:

The logging output of the mysql container is the same, same warnings. Why don’t I see anything in the browser?

mysql database I can log into the database, using docker exec -it e46fae64e430 mysql -p todos. But they don’t point to the same todos database. The ‘composer’ version is empty, the other contains the test data I entered before.

[liquidkey]

I was having trouble getting docker-compose tutorial working. mysql container was not able to initialize the database. I found that volume “todo-mysql-data” from previous tutorial was still there and probably that was conflicting. So i removed that volume and tried again and it worked.

[EelcoA]

I have it running now, adding the following to the docker-compose.yml to force the apps to use the previously created network ‘todo-app’:

networks:
  default:
    external:
      name: todo-app

This works now, but clearly, the default network should have worked as well. Anybody a suggestion what is causing this behaviour? A bug in docker(compose)? Something I did wrong somewhere?

Also what confuses me is that the mysql database in both situaties use the same volumes and give the same output on SHOW VARIABLES WHERE Variable_Name LIKE "%dir" ;, but show other data.