DBND Plugins

How to extend the DBND SDK's functionality via plugins.

DBND Loading Plugins at Startup

You can extend the DBND SDK's functionality via pip-installable plugins.
Several DBND packages do exactly that, including dbnd-aws, dbnd-hdfs, dbnd-gcp, and more.

You can find the full list of dbnd plugins here.

DBND uses the pluggy library to load plugins during the bootstrap phase, which takes place every time you run a Pipeline. More information about pluggy can be found here.

Making Plugins Work with DBND

There are two ways to make DBND to use your plugins:

Via dbnd configuration:
You can set the plugins config in the core section to your list of modules (separated by comma).
DBND will try to import each module and load it.

For example:

[core]
plugins = my_plugin._plugin

Via setuptools entrypoint:
You can add a dbnd entry_point to you setup.py.
For example:

entry_points={"dbnd": ["dbnd-aws = dbnd_aws._plugin"]},

You need to place your setup code in your _plugin.py file.

Writing Your Plugin Setup Code:

Your package source should contain the following function:

@dbnd.hookimpl
def dbnd_setup_plugin():
   pass

To change the order in which your plugin is called relatively to other plugins, you can use the tryfirst or trylast flags. This way, your plugin is called first or last, respectively.

For example:

@dbnd.hookimpl(trylast=True)

Useful functions to call in dbnd_setup_plugin:
register_config_cls - Registers a new config
Register_file_system - Useful for registering a new type of file system (for example, your own implementation of S3)
register_marshaller - To register your own custom defined marshaler (see creating a custom marshaller)
register_value_type - To register a custom value type

Additional dbnd hooks

Other than dbnd_setup_plugin there are other hooks that you can use together with the @dbnd.hookimpl decorator to influence dbnd behaviour.

dbnd_get_commands - Called from main cli entry point, allows to register new commands
dbnd_task_run_context - Uses this context manager when running task_run


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