Declare volumes in docker compose

Question

I am using docker-compose file generated by docker-app

docker-app  render | docker-compose -f - up

The docker app file looks like this and it works as expected. But I am not able to use volumes.

I use -v parameter while using docker run command like this...

-v /my/custom3399:/etc/mysql/conf.d  
-v /storage/mysql/datadir3399:/var/lib/mysql 

How do I declare volumes in compose file?

# vi hello.dockerapp
# This section contains your application metadata.
# Version of the application
version: 0.1.0
# Name of the application
name: hello
# A short description of the application
description:
# Namespace to use when pushing to a registry. This is typically your Hub username.
#namespace: myHubUsername
# List of application maitainers with name and email for each
maintainers:
  - name: root
    email:
# Specify false here if your application doesn't support Swarm or Kubernetes
targets:
  swarm: false
  kubernetes: false

--
# This section contains the Compose file that describes your application services.

version: "3.5"
services:
  mysql:
    image: ${mysql.image.version}
    environment:
      MYSQL_ROOT_PASSWORD: india${mysql.port}
    ports:
      - "${mysql.port}:3306"


--
# This section contains the default values for your application settings.
mysql.image.version: shantanuo/mysql:5.7
mysql.port: 3391

---

update:

The script mentioned above works well. But once I add volumes, I get an error:

version: "3.5"
services:
  mysql:
    image: ${mysql.image.version}
    environment:
      MYSQL_ROOT_PASSWORD: india${mysql.port}
    ports:
      - "${mysql.port}:3306"
    volumes:
      - type: volume
        source: mysql_data
        target: /var/lib/mysql

volumes:
  mysql_data:
    external: true

---

And the error is:

docker-app  render | docker-compose -f - up
Recreating e5c833e2187d_hashi_mysql_1 ... error

ERROR: for e5c833e2187d_hashi_mysql_1  Cannot create container for service mysql: Duplicate mount point: /var/lib/mysql

ERROR: for mysql  Cannot create container for service mysql: Duplicate mount point: /var/lib/mysql
ERROR: Encountered errors while bringing up the project.

---

As mentioned in the comment, the rendered output is as follows:

#  /usr/local/bin/docker-app  render
version: "3.5"
services:
  mysql:
    environment:
      MYSQL_ROOT_PASSWORD: india3391
    image: shantanuo/mysql:5.7
    ports:
    - mode: ingress
      target: 3306
      published: 3391
      protocol: tcp
    volumes:
    - type: volume
      source: mysql_data
      target: /var/lib/mysql
volumes:
  mysql_data:
    name: mysql_data
    external: true

Answer 1

This issue was resolved once I changed the directory name.

# cd ..
# mv hashi/ hashi123/
# cd hashi123

Not sure how this worked. But since I am able to start the server stack, I am posting it as answer.