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#ask-ai
Title
# ask-ai
j

Jacob Marcil

02/07/2024, 4:16 PM
@Scout is there a way to create a graph asset with multiple steps that succedd even if some steps failed?
s

Scout

02/07/2024, 4:16 PM
Based on the documentation, Dagster does not provide a built-in way to create a graph asset where the entire graph succeeds even if some of the steps within it fail. Typically, the failure of a step within a graph will cause the execution of the graph to fail, as each step's success is usually a prerequisite for the execution of downstream steps. However, there are some strategies you could consider to handle partial failures within a graph: 1. Error Handling within Ops: You can implement error handling within your ops to catch exceptions and prevent them from propagating. This way, an op can fail internally, but you can catch the exception and return a default value or a marker that indicates failure, allowing downstream ops to execute. 2. Custom Logic for Step Execution: You could write custom logic to determine whether downstream steps should execute based on the results or status of upstream steps. This would involve more complex orchestration and potentially using hooks or custom execution strategies. 3. Asset Sensors or Observers: You could use asset sensors or observers to monitor the materialization of assets and trigger downstream computations based on custom logic that takes into account the success or failure of upstream assets. 4. Manual Intervention: In cases where automated handling is not feasible, you might resort to manual intervention to decide when and how to proceed with the execution of downstream steps after a failure. It's important to note that these strategies may require careful consideration of your specific use case and the semantics of your data processing. If you need the graph to succeed despite some steps failing, you will need to ensure that the downstream steps can handle the absence or placeholder values of the outputs from the failed steps. For more detailed guidance and potential code examples, you should refer to the [Graph-backed asset documentation](https://docs.dagster.io/concepts/assets/graph-backed-assets) provided by Dagster.
j

Jacob Marcil

02/07/2024, 4:18 PM
@Scout Can I create a graph asset that continue to the end of the graph if a DynamicOutput fail.
s

Scout

02/07/2024, 4:19 PM
In Dagster, when using
DynamicOutput
within a graph, the failure of a dynamic step (i.e., an op that yields
DynamicOutput
) will typically cause the execution of the graph to fail. This is because dynamic outputs are often used to represent a variable number of outputs from an op, which may then be consumed by downstream ops. If a dynamic step fails, the downstream ops that depend on its outputs will not have the data they need to execute. However, if you want to continue executing the rest of the graph even if a
DynamicOutput
fails, you would need to implement custom error handling within your ops. Here's a general approach you could take: 1. Error Handling in Ops: Within the op that yields
DynamicOutput
, you can catch exceptions and instead yield a special
DynamicOutput
that indicates a failure. Downstream ops would need to be designed to handle these special failure-indicating outputs appropriately. 2. Branching Logic: Implement branching logic within your graph to handle the success or failure paths differently. This could involve checking for the presence of failure-indicating outputs and conditionally executing different branches of your graph. 3. Custom IO Managers: Use custom IO managers that can handle exceptions during the storage and retrieval of dynamic outputs. This way, even if an error occurs during the processing of a dynamic output, the IO manager can ensure that the rest of the graph continues to execute. It's important to note that these approaches require careful design to ensure that your graph's semantics are correct and that downstream ops can handle the absence or special handling of failed dynamic outputs. The documentation does not provide a direct example of a graph asset that continues to the end of the graph if a
DynamicOutput
fails. For more specific guidance on handling dynamic outputs and implementing error handling within your ops, you should refer to the [Op retries documentation](https://docs.dagster.io/concepts/ops-jobs-graphs/op-retries) and the [Dynamic Output documentation](https://docs.dagster.io/concepts/solids-pipelines/dynamic-computation) provided by Dagster.
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