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#ask-ai
Title
# ask-ai
e

elgreco

02/26/2024, 7:01 PM
How do we make an observable asset factory receive the resources that I provide by name?
s

Scout

02/26/2024, 7:01 PM
To define an observable source asset that receives resources by name, you would typically use the
resource_defs
parameter when decorating your function with
@observable_source_asset
. The
resource_defs
parameter allows you to specify resource definitions that may be required by the asset. Here is an example based on the documentation:
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python from dagster import observable_source_asset, ResourceDefinition  # Define your resources my_resource = ResourceDefinition(...)  @observable_source_asset(resource_defs={'my_resource': my_resource}) def my_observable_asset():     # Your asset logic here     ...
In this example,
my_resource
is a
ResourceDefinition
that you want to make available to
my_observable_asset
. By including it in the
resource_defs
dictionary with the key
'my_resource'
, you can then access this resource within your asset definition using the provided context. Please note that the
resource_defs
parameter is marked as experimental in the documentation, which means that this API may change in future versions of Dagster, even between dot releases. Always refer to the latest documentation for the most up-to-date information on using this feature.
e

elgreco

02/26/2024, 7:03 PM
@Scout I already defined all the resources in the global definitions, in the observable source asset factory I just want to pass the keys of my configurable resource, how many ways are there to achieve this? With examples please
s

Scout

02/26/2024, 7:03 PM
In Dagster, when you have already defined resources globally and you want to use them in an observable source asset factory, you can pass the keys of the resources to the asset factory. This is typically done using the
required_resource_keys
parameter, which specifies the set of resource keys that the asset requires. Here's an example of how you might define an observable source asset factory with `required_resource_keys`:
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python from dagster import observable_source_asset  # Assuming 'my_resource' is a key for a resource defined globally in your repository  @observable_source_asset(required_resource_keys={'my_resource'}) def my_asset(context):     # You can access the resource using the context     my_resource_instance = context.resources.my_resource     # Your asset logic here     ...
In this example,
my_asset
is an observable source asset that requires a resource with the key
'my_resource'
. By specifying this in
required_resource_keys
, Dagster knows to provide the resource associated with that key to the asset when it is materialized. If you have multiple resources, you can include all the required keys in the set:
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python @observable_source_asset(required_resource_keys={'my_resource', 'another_resource'}) def my_asset(context):     # Access multiple resources     my_resource_instance = context.resources.my_resource     another_resource_instance = context.resources.another_resource     # Your asset logic here     ...
These examples show how to specify resource dependencies by their keys for observable source assets. The actual resource instances are defined elsewhere in your repository, and you are simply telling Dagster which ones this particular asset needs to operate. Remember to always check the latest Dagster documentation for the most current practices, as APIs and features can evolve over time.
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