Fetching Workflow Result

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1

How can I get a workflow’s result if I don’t know what the result type will be (or if there even is one)? Here is my current code:

    public String getWorkflowResult(WorkflowExecutionInfo executionInfo, String workflowId, String runId) {

        var status = executionInfo.getStatus();

        Optional<String> optRunId = Optional.ofNullable(runId).filter(s -> !s.isEmpty());
        WorkflowStub workflowStub = client.newUntypedWorkflowStub(workflowId, optRunId, Optional.empty());

        return switch (status) {
            case WORKFLOW_EXECUTION_STATUS_TERMINATED, WORKFLOW_EXECUTION_STATUS_TIMED_OUT, WORKFLOW_EXECUTION_STATUS_CANCELED, WORKFLOW_EXECUTION_STATUS_RUNNING ->
                    "void";
            default -> workflowStub.getResult(Object.class).toString();
        };

    }

This is called for each run of a workflow, but it somehow is running forever.

3

Hi @eric-gassel

I am not aware right now of any way to infer the type a workflow returns if you don’t have access to the workflow interface.

what do you mean by this?

getResult is a blocking operation. If the workflow status == WORKFLOW_EXECUTION_STATUS_RUNNING, it will wait/block your code until the workflow is completed. For any other status != WORKFLOW_EXECUTION_STATUS_COMPLETED (and WORKFLOW_EXECUTION_STATUS_RUNNING) the invocation to getResult will throw an exception (You might want to add WORKFLOW_EXECUTION_STATUS_FAILED to your switch)

4

Looking at the getResult Javadoc, I would rely on exception handling rather than WorkflowExecutionInfo.getStatus()

try{
   return getResult... 
}catch(Exception e){
   return "void";
}

The reason is that the SDK query the visibility store and there is a delay between the workflow data and the data that the visibility store shows (i.e. executionInfo.getStatus() could be = WORKFLOW_EXECUTION_STATUS_RUNNING in the visibility store, but the actual workflow is actually completed).

5

You can implement your own DataConverter that is going to deserialize results of unknown types into the Object type.