Using resources in projects

Prerequisites

Before following this guide, you will need to create a project with the create-dagster CLI.

Assets, asset checks, and sensors in Dagster frequently require resources that are instantiated elsewhere in the project.

For example, if you have created a new Dagster project with dg called my_project, you can define the resources at src/my_project/defs/aresource.py:

src/my_project/defs/aresource.py

import dagster as dg


class AResource(dg.ConfigurableResource): ...

You can then make that resource available anywhere else in your project by defining a @dg.Definitions function:

src/my_project/defs/resources.py

from my_project.defs.aresource import AResource

import dagster as dg


@dg.definitions
def defs() -> dg.Definitions:
    return dg.Definitions(
        resources={"a_resource": AResource(name="foo")},
    )

You can now use the resource elsewhere in your project:

src/my_project/defs/assets.py

from my_project.defs.aresource import AResource

import dagster as dg


@dg.asset
def asset_one(a_resource: AResource): ...

Scaffolding resources

To create a resource dictionary like the above, you can run the following:

dg scaffold defs dagster.resources resources.py

which will create:

src/<project_name>/defs/resources.py

import dagster as dg


@dg.definitions
def resources() -> dg.Definitions:
    return dg.Definitions(resources={})

and you can fill out the resource dictionary as needed.