Using resources in dg projects

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

For example you have an asset:

# in defs/asset_one.py
from my_project.resources import AResource

import dagster as dg


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

And a separately defined resource at the root of the project:

# src/resources.py
import dagster as dg


class AResource(dg.ConfigurableResource): ...

Resources can be added at any level in the defs hierarchy by creating a Definitions object.

from my_project.resources import AResource

import dagster as dg

defs = dg.Definitions(
    resources={"a_resource": AResource(name="foo")},
)

Resource binding can happen at any level of the hierarchy. Which means that if you moved asset_one in this example to be in a subdirectory, you could leave the existing resources.py file at src/defs/resources.py.

src
└── resource_docs
    ├── definitions.py
    ├── defs
    │   ├── assets
    │   │   └── asset_one.py # contains def asset_one():
    │   └── resources.py # contains AResource()
    └── resources.py # contains class AResource