Mount volumes for local dev?

[brandontamm]

I add volume in hopes to map the /magento/htdocs directory from container to host for local dev but all I get is an empty directory - any ideas what I am doing wrong or how to mount volume correctly?

`version: '2.1'

services:
mariadb:
image: 'mariadb:latest'
environment:
- MYSQL_ROOT_PASSWORD=password
- MYSQL_DATABASE=magento
healthcheck:
test: "/usr/bin/mysql --user=root --password=password --execute "SHOW DATABASES;""
timeout: 5s
retries: 20
volumes:
- 'magento_database:/var/lib/mysql'
magento:
image: 'jamesbrink/magento:2.2-sass-sd'
environment:
- MARIADB_HOST=mariadb
- MARIADB_PORT_NUMBER=3306
- MAGENTO_DATABASE_USER=root
- MAGENTO_DATABASE_PASSWORD=password
- MAGENTO_DATABASE_NAME=magento
- MAGENTO_ADMINURI=admin
- MAGENTO_HOST=localhost
- ENABLE_SAMPLE_DATA=true
- APACHE_LOG_LEVEL=warn
ports:
- '80:80'
- '443:443'
volumes:
- './src:/magento/htdocs'
depends_on:
mariadb:
condition: service_healthy

volumes:
magento_database:
driver: local
`