Linton Ye
02/06/2024, 7:19 PMScout
02/06/2024, 7:19 PMLinton Ye
02/06/2024, 7:23 PMScout
02/06/2024, 7:23 PMRetryPolicy
on your assets to automatically retry them a certain number of times with a specified delay if they fail. This is useful for transient failures that might succeed upon a subsequent attempt. 2. Re-execution: Dagster provides several re-execution options that allow you to re-run parts of your job: - All Ops: Re-execute the entire job from scratch. - Selected Op(s): Re-execute only the selected ops, regardless of their status. - From Selected: Re-execute the job downstream from the selected ops. - From Failure: Re-execute the job, skipping ops that completed successfully. This option is enabled when the run has failed, and you want to re-run the failed op and all downstream dependencies. 3. Asset Observability: Dagster allows you to attach code versions to your assets, and the UI can indicate when an asset has a different code version than the code version used for its most recent materialization. This can help you identify which assets may need to be re-run due to changes. 4. Subset Execution: Within the UI, you can select a subset of assets to re-run by specifying the desired asset names. This allows you to target only the assets that need to be re-executed. 5. Custom Logic: If the built-in re-execution strategies do not fit your needs, you can implement custom logic to handle re-execution. For example, you could use sensors to monitor asset materializations and trigger re-execution based on custom criteria. 6. Partitioned Assets: If your assets are partitioned, you can use backfills to re-materialize assets across specific partitions. This can be useful if you want to re-run assets for certain time windows or datasets. 7. Run-Level Retries: For ensuring that your ops and assets execute even after a crash, you can set up run-level retries, which will retry the run if it fails for any reason. It's important to note that the exact approach will depend on your specific use case and the nature of the failures you're encountering. For instance, if you have a set of assets that are independent and you want to stop the entire run if any asset fails, you might need to implement custom logic to handle this scenario, as the standard behavior in Dagster is to continue executing other assets in parallel even if one fails. For more detailed guidance on implementing these strategies, you should refer to the Dagster documentation on re-execution, retry policies, and asset materialization.Linton Ye
02/06/2024, 7:27 PMScout
02/06/2024, 7:27 PMLinton Ye
02/06/2024, 7:54 PMScout
02/06/2024, 7:54 PMOptional
are not required to be specified in the config, and they have an implicit default value of None
. If you want to make a config field optional, you can define it using the Optional
type hint from the typing
module. Here's an example of how you can define an asset with an optional config: python from typing import Optional from dagster import asset @asset(config_schema={"optional_param": Optional[str]}) def my_asset(context): optional_param = context.op_config.get("optional_param") # Your asset logic here return "Result with optional param: {}".format(optional_param)
In this example, optional_param
is an optional config parameter. If it is not provided in the run config, it will default to None
. When you materialize this asset, you can choose to provide a value for optional_param
or omit it entirely. If you omit it, the asset will still execute, using the default value of None
. Remember that if you want to provide a default value other than None
, you can do so by setting a default in the config schema: python from typing import Optional from dagster import asset, Field @asset(config_schema={"optional_param": Field(Optional[str], default_value="default_value")}) def my_asset_with_default(context): optional_param = context.op_config["optional_param"] # Your asset logic here return "Result with optional param: {}".format(optional_param)
In this case, if optional_param
is not provided in the run config, it will default to the string "default_value"
. Using these patterns, you can define assets with optional configs that provide flexibility in how they are executed and materialized.