how do I get the list of asset keys produced by a multi_asset?

To get the list of asset keys produced by a

@multi_asset

, you can inspect the

outs

parameter of the

@multi_asset

decorator. The

outs

parameter is a dictionary that maps output names to

AssetOut

objects, which represent the produced assets. Each

AssetOut

object can have an

AssetKey

associated with it, which uniquely identifies the asset. Here's an example from the documentation that illustrates how you might define a

@multi_asset

with multiple outputs:

python @multi_asset(     outs={         "output1": AssetOut(key=AssetKey(["group_name", "output1"])),         "output2": AssetOut(key=AssetKey(["group_name", "output2"])),     } ) def my_multi_asset(context):     # Your computation logic here     ...

In this example, the

@multi_asset

produces two assets with keys

AssetKey(["group_name", "output1"])

and

AssetKey(["group_name", "output2"])

. To get a list of these asset keys, you would iterate over the values of the

outs

dictionary and collect the keys:

python asset_keys = [asset_out.key for asset_out in my_multi_asset.outs.values()]

This would give you a list of

AssetKey

objects representing the assets produced by the

@multi_asset

. Keep in mind that this is a conceptual explanation; the exact way to access the

outs

attribute will depend on the context in which you're working with the

@multi_asset

.

@Scout is there a way to get it from the multi_asset object itself?

In Dagster, the

multi_asset

decorator is used to define a computation that produces multiple assets. However, the

multi_asset

object itself, as defined by the decorator, does not directly expose a method or property to retrieve the list of asset keys it produces. The asset keys are defined in the

outs

parameter of the

multi_asset

decorator, which maps output names to

AssetOut

objects. If you want to programmatically access the asset keys produced by a

multi_asset

, you would typically do so by inspecting the

outs

parameter of the decorator in the code where the

multi_asset

is defined. This is a static analysis approach and would require you to look at the source code or the metadata of the

multi_asset

definition. As of my knowledge cutoff date in April 2023, there is no built-in function or method provided by Dagster that allows you to dynamically retrieve the list of asset keys from the

multi_asset

object itself after it has been defined. If such functionality is required, it would likely involve introspection or reflection techniques specific to the Python programming language, or it would require a feature update from Dagster that provides this capability. For dynamic scenarios or when working with the Dagster system at runtime, you would typically interact with the asset catalog or asset graph within the Dagster instance to query and retrieve information about assets, including their keys. However, this would not be done through the

multi_asset

object directly but rather through Dagster's APIs for asset introspection. If you need to retrieve asset keys at runtime or from an instance of Dagster, you may want to explore Dagster's asset catalog or asset graph APIs, which can provide information about the assets that are part of your Dagster repository. These APIs allow you to query the system for assets and their metadata, which includes asset keys.