What is difference between software deinfed asset and graph based asset? Give me an example.

A software-defined asset in Dagster is an object that couples an asset to the function and upstream assets that are used to produce its contents. It is a declarative approach to data management, where code is the source of truth on what data assets should exist and how those assets are computed. This means that the asset's existence, computation, and relationships are explicitly defined in code, rather than being inferred or observed after the fact. On the other hand, a graph-based asset refers to an asset that is part of an asset graph. An asset graph is a collection of software-defined assets that shows how they are interconnected. It is a critical tool for understanding and working with data, providing insights into the lineage of assets, their dependencies, and the impact of changes. Here's an example of a software-defined asset:

python @asset def my_asset(upstream_asset):     # Logic to compute the asset from the upstream_asset     return computed_value

In this example,

my_asset

is a software-defined asset that depends on

upstream_asset

. The function

my_asset

contains the logic to compute the asset's contents. For a graph-based asset, consider the following example:

python @op def extract():     # Logic to extract data     return data  @op def transform(extracted_data):     # Logic to transform data     return transformed_data  @op def load(transformed_data):     # Logic to load data     return loaded_data  @asset @graph def etl():     return load(transform(extract))

In this example,

etl

is a graph-based asset that is composed of a graph of operations (

extract

,

transform

, and

load

). The

@graph

decorator is used to define a graph of ops, and the

@asset

decorator indicates that the result of this graph is a software-defined asset. The asset graph would show the dependencies between these operations and how they contribute to the creation of the

etl

asset. The key difference is that while all graph-based assets are software-defined assets, not all software-defined assets are necessarily graph-based. A software-defined asset can be a simple asset defined by a single function, while a graph-based asset is specifically part of an interconnected graph of assets.