Best way to instantiate a client resource

[adjit]

Hello, I have a resource, following what was done for dagster_aws.s3 and in the docs. it looks like this -

class MyClient:
    def func1():
        pass

class MyResource(ConfigurableResource):
    def get_client(self): 
        return MyClient()

What is the benefit to do it the above way, vs setting your client up when on resource initialization?
IE-

class MyResource(ConfigureableResource):
    my_client: MyClient

    def __init__(self):
        my_client = MyClient()

[garethbrickman]

The primary benefit of using the get_client method in the MyResource class, as opposed to initializing the client directly in the constructor, is flexibility and separation of concerns:

Deferred Initialization:
By using a method like get_client, you can defer the creation of the MyClient instance until it is actually needed. This can be useful in scenarios where the resource might not always be used, or where the initialization of the client is expensive and should be delayed until absolutely necessary.

Configuration Management:
The ConfigurableResource class in Dagster is designed to handle structured configuration. By separating the client creation into a method, you can more easily manage and modify the configuration parameters that might be needed to initialize the client. This is particularly useful if the client requires dynamic configuration values that are only available at runtime.

Testing and Mocking:
Separating the client creation into a method makes it easier to mock the client for testing purposes. You can override the get_client method in your tests to return a mock client, which can simplify unit testing and make your tests more isolated and reliable.

Resource Lifecycle Management:
Dagster provides hooks for managing the lifecycle of resources, such as setup_for_execution and teardown_after_execution. By using a method to create the client, you can integrate these lifecycle hooks more effectively, ensuring that resources are properly initialized and cleaned up.