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Title
# ask-ai
s

Simon Ammer

03/11/2024, 1:21 PM
How can I specify a different resource depending on whether I run Dagster locally or on AWS?
s

Scout

03/11/2024, 1:21 PM
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:
Copy code
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:
Copy code
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
ce"}) def my_asset(context): # Use context.resources.my_resource as needed pass ``` Remember to set the
MY_ENVIRONMENT
environment variable to either "local" or "aws" depending on where you are running Dagster. Please note that the exact implementation details may vary based on your specific use case and the version of Dagster you are using. Always refer to the latest Dagster documentation for the most accurate and up-to-date guidance.
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