How can I specify a different resource depending on whether I run Dagster locally or on AWS?

To specify different resources for local and AWS environments in Dagster, you can use environment-specific configuration files or environment variables to conditionally load the appropriate resource settings. Here's a step-by-step guide based on the documentation: 1. Define Configurable Resources: Create resource definitions that can be configured differently based on the environment. For example, you might have a resource for connecting to a database that can be configured with different credentials for local and AWS environments. 2. Use Environment Variables: Resources can be configured using environment variables, which is useful for secrets or other environment-specific configuration. You can define environment variables in your local environment or set them in your AWS deployment (e.g., in ECS task definitions or EC2 instance environment configurations). 3. Conditional Configuration in

dagster.yaml

: In your

dagster.yaml

file, you can specify different configurations for resources based on environment variables. For example, you can use an

EnvVar

to populate a string config field on a resource, and the value of the environment variable will be evaluated when a run is launched. 4. Separate Configuration Files: If you prefer not to use environment variables, you can maintain separate configuration files for local and AWS environments. You would then load the appropriate configuration file based on where you are running Dagster. 5. Set

DAGSTER_HOME

: Ensure that the

DAGSTER_HOME

environment variable is set correctly in each environment. This variable determines where Dagster looks for the

dagster.yaml

file. 6. Use the Resource in Assets: When defining your assets, use the resources by referencing them in the asset definitions. Dagster will inject the appropriate resource instance based on the configuration loaded at runtime. Here's an example of how you might define a resource that uses environment variables for configuration:

python
from dagster import resource, Field, String

@resource({
    "env": Field(String, is_required=False, default_value="local")
})
def my_resource(init_context):
    env = init_context.resource_config["env"]
    if env == "local":
        # Configure resource for local environment
        return LocalResource()
    elif env == "aws":
        # Configure resource for AWS environment
        return AWSResource()
    else:
        raise Exception(f"Unknown environment: {env}")

In your

dagster.yaml

, you can then set the

env

field based on an environment variable:

yaml
resources:
  my_resource:
    config:
      env: ${MY_ENVIRONMENT}

And in your assets, you would use the `my_resource`: ```python from dagster import asset @asset(required_resource_keys={"my_resour