[BUG] Deprovision workflow returns 500 error when workflow ID not found

[dbwiddis]

What is the bug?

When attempting to deprovision a workflow with a document id that does not exist, a 500 (INTERNAL_SERVER_ERROR) response is given.

How can one reproduce the bug?

1. Provision a workflow.
2. Delete the document from the state index with that workflow ID.
3. Attempt to deprovision the workflow.

[2024-07-25T19:28:08,429][ERROR][o.o.f.t.DeprovisionWorkflowTransportAction] [eb67737de9cbbf02c477726fc8ebf46d] Failed to get workflow state for workflow 3Uqby5ABgrORC4V3o7kx
org.opensearch.flowframework.exception.FlowFrameworkException: Fail to find workflow 3Uqby5ABgrORC4V3o7kx

<trace truncated>

[2024-07-25T19:28:08,429][INFO ][c.a.c.e.logger           ] [eb67737de9cbbf02c477726fc8ebf46d] POST /_plugins/_flow_framework/workflow/3Uqby5ABgrORC4V3o7kx/_deprovision - 500 INTERNAL_SERVER_ERROR 74 2

What is the expected behavior?

The wrong workflow ID should return a 400-series error, either not found, or bad request.

Do you have any additional context?

The error is automatically wrapped from the exception thrown in the Get Workflow State action

flow-framework/src/main/java/org/opensearch/flowframework/transport/DeprovisionWorkflowTransportAction.java

Lines 108 to 126 in 034dff7

	client.execute(GetWorkflowStateAction.INSTANCE, getStateRequest, ActionListener.wrap(response -> {
	context.restore();
	Set<String> deleteAllowedResources = Strings.tokenizeByCommaToSet(allowDelete);
	// Retrieve resources from workflow state and deprovision
	threadPool.executor(DEPROVISION_WORKFLOW_THREAD_POOL)
	.execute(
	() -> executeDeprovisionSequence(
	workflowId,
	response.getWorkflowState().resourcesCreated(),
	deleteAllowedResources,
	listener
	)
	);
	}, exception -> {
	String errorMessage = "Failed to get workflow state for workflow " + workflowId;
	logger.error(errorMessage, exception);
	listener.onFailure(new FlowFrameworkException(errorMessage, ExceptionsHelper.status(exception)));
	}));

That should be using this workflow state 404 error:

flow-framework/src/main/java/org/opensearch/flowframework/transport/GetWorkflowStateTransportAction.java

Line 86 in 034dff7

listener.onFailure(new FlowFrameworkException("Fail to find workflow status of " + workflowId, RestStatus.NOT_FOUND));

This exception is then passed to ExceptionsHelper.status() which does not understand the FlowFrameworkException type.

Best fix is to change FlowFrameworkException to extend OpenSearchException and override status() so we can hit this line:

            if (t instanceof OpenSearchException) {
                return ((OpenSearchException) t).status();

See code for OpenSearchStatusException and adapt.