Synchronizing data in a Docker developer environment

You have the option to launch a Docker environment in developer mode, which provides an active development environment with full, writable file system permissions.

If you choose this option, the Magento Commerce application works only if the Docker containers have access to the Magento Commerce application data. You can provide access either by directly mapping the current working directory or by using a file synchronization tool.

The Magento Cloud Docker docker-build command provides the --sync-engine <type> option to select the file synchronization behavior when you build the docker-compose.yml configuration file. You can select from the following options:

File synchronization options

Option Description
native Maps the current working directory to the /app directory on each volume, which provides direct access to the data without requiring any synchronization. The native option is the default and works for Linux hosts. On macOS or Windows hosts, this option results in extremely slow performance in the Docker environment.
mutagen Uses Mutagen for file synchronization. When you select Mutagen, you must install Mutagen on your host operating system before you launch Docker in developer mode. Use this option on macOS or Windows hosts.
docker-sync Uses docker-sync for file synchronization. When you select docker-sync, you must [install docker-sync] on your host operating system before you launch Docker in developer mode. Use this option on macOS or Windows hosts.

When you start Docker with the native file synchronization option, the current working directory maps to the /app folder in the containers:

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  fpm:
    volumes:
      - '.:/app'
  build:
    volumes:
      - '.:/app'
  deploy:
    volumes:
      - '.:/app'
  web:
    volumes:
      - '.:/app'
  cron:
    volumes:
      - '.:/app'

Configure file synchronization

If you do not specify a --sync-engine option, the Magento Docker build uses the native option.

On macOS or Windows systems, you can configure file synchronization using Mutagen or docker-sync by adding the --sync-engine="<type>" option to the ece-docker build:compose command.

For example:

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./vendor/bin/ece-docker build:compose --mode="developer" --sync-engine="mutagen"

For detailed configuration instructions, see launch Docker in developer mode.