Creating plugins

It is possible to create plugins to the dtool command line tool. There are two different types of plugins: command line tools and backend storage brokers. The former allows a developer to add custom extensions to the dtool command. The latter allows a developer to create an interface for talking to a new type of storage. One could for example create a storage broker to interface with Amazon S3 object storage.

Extending the dtool command line tool

Information on how to extend the dtool command line tool is available in the README file of dtool-cli.

Concrete examples making use of this plugin system are:

Creating an interface to a new type of storage

Below are the steps required to create a storage broker for allowing dtool to interact with a new backend. A concrete example making use of this plugin system is dtool-irods.

  1. Examine the code in dtoolcore.storagebroker.DiskStorageBroker.

  2. Create a Python class for your storage, e.g. MyStorageBroker

  3. Add a MyStorageBroker.key` attribute to the class, this key is used to lookup an appropriate storage broker when interacting with a dataset

  4. Add a dtoolcore.FileHasher instance that matches the hashing algorithm used by your storage to your MyStorageBroker.hasher attribute

  5. Add implementations for all the public functions in dtoolcore.storagebroker.DiskStorageBroker class to MyStorageBroker

  6. Expose the MyStorageBroker class as a dtool.storage_broker entrypoint, e.g. add a section along the lines of the below to the setup.py file:

    entry_points={
    "dtool.storage_brokers": [
        "MyStorageBroker=my_dtool_storage_plugin:MyStorageBroker",
    ],
},