what is the difference between ConfigurableResource.create_resource() and ConfigurableResource.setup_for_execution()?

The

ConfigurableResource.create_resource()

method and the

ConfigurableResource.setup_for_execution()

method serve different purposes in the lifecycle of a resource in Dagster. 1. `ConfigurableResource.create_resource()`: This method is used to create and return the actual resource object that will be used during the execution of assets or jobs. When you define a resource by extending

ConfigurableResource

, you can override the

create_resource()

method to construct and return the resource instance. This method is called during the initialization of the resource, and it receives an

InitResourceContext

object which provides access to the resource's configuration and other initialization parameters. 2. `ConfigurableResource.setup_for_execution()`: This method is intended for setting up any internal state or performing actions that are necessary before the resource can be used for execution. It is a place to perform any additional initialization that may be required after the resource object has been created but before it is used by assets or jobs. The

setup_for_execution()

method is not a standard method defined on

ConfigurableResource

in the documentation, but it may be mentioned in the context of user discussions or examples as a pattern for initializing internal state. In summary,

create_resource()

is a method you define to construct the resource object, while

setup_for_execution()

is a pattern that may be used to perform additional setup actions after the resource object has been created. The latter is not a standard method on

ConfigurableResource

and may be specific to certain use cases or examples discussed by users.

are they both called during the resource initialization? @Scout

Based on the documentation,

ConfigurableResource.create_resource()

is the method that is called during the resource initialization process. This method is responsible for creating the resource instance that will be used during the execution of assets or jobs. It is a part of the standard lifecycle of a resource in Dagster and is defined by the user when extending

ConfigurableResource

. The

setup_for_execution()

method is not mentioned in the documentation as part of the standard resource lifecycle in Dagster. Therefore, it is not a method that is called during resource initialization by the Dagster framework itself. It may be a pattern or a method that users implement in their own resource classes for additional setup, but it is not a part of the

ConfigurableResource

base class or its standard methods. To clarify, only

create_resource()

is part of the documented resource initialization process in Dagster. If

setup_for_execution()

is used, it would be a custom method implemented by the user and would need to be called explicitly by the user's code, not by Dagster's resource initialization process. Resource defs provided to a job replace ... button Community Memo: Pythonic Config and Reso... button Log the origin of required resources whe... button Resources | Dagster button Thank you for your feedback!

@Scout when would I use the configure_at_launch() method?

The

configure_at_launch()

method is used when you want to defer the configuration of a

ConfigurableResource

until the time a job or asset is launched, rather than at the time the code is loaded. This can be particularly useful in scenarios where you want to provide different configurations for a resource on a per-run basis, or when the configuration should be determined dynamically at runtime. Here are some situations where you might use `configure_at_launch()`: 1. Environment-Specific Configuration: If your resource needs to connect to different databases or services depending on the environment (development, staging, production), you can use

configure_at_launch()

to specify the appropriate connection strings or credentials at launch time. 2. Dynamic Configuration: In cases where the configuration of a resource depends on external factors that are only known at runtime, such as the result of a previous computation or user input,

configure_at_launch()

allows you to provide that configuration when you launch the job or asset. 3. Secrets Management: When dealing with sensitive information such as API keys or passwords, you might not want to hardcode these values or load them when the code initializes. Instead, you can use

configure_at_launch()

to pull these values from a secure location at launch time. 4. Testing and Mocking: When writing tests, you may want to provide different resource configurations without changing the code.

configure_at_launch()

enables you to pass in test configurations when you execute the job or asset in your test suite. 5. User-Driven Configuration: If the configuration should be specified by the user who is launching the job or asset, such as through a UI or command-line interface,

configure_at_launch()

allows the user to input the necessary configuration at that time. By using

configure_at_launch()

, you can ensure that the resource is configured with the most up-to-date and context-specific settings, providing flexibility and control over how resources are initialized for each execution.

@Scout will a job level config overwrite a definitions level config for the same resource?

Yes, a job-level config will overwrite a definitions-level config for the same resource. When you provide a resource configuration at the job level, it takes precedence over the configuration provided at the definitions level. This allows you to customize the behavior of resources for specific jobs, even if a default configuration is provided at a higher level. Here's how the precedence works: 1. Definitions Level: This is the global or default configuration for resources that you define in your

Definitions

. It acts as a base configuration that applies to all jobs unless overridden. 2. Job Level: When you specify a configuration for a resource at the job level, it replaces the definitions-level configuration for that resource within the context of the job. This allows you to tailor the resource configuration to the specific needs of the job. If you want to merge configurations from both levels, you would need to handle that explicitly in your code, as the default behavior is to replace the definitions-level config with the job-level config for the resources specified at the job level.