Update 2/3/2025:

• We have the code ready but need to find a safe way to ship this. We only do the validation when not restoring from a checkpoint (indicating a fresh start of the processor). But there are some users of onError=dlq and validationAction=dlq that are also using a sample_stream_solar source (where checkpoint is disabled). The current implementation could break them.
• Ideas:

• • skip the validation for sample sources?
  • use stream processor feature flags (a bit cumbersome)

There are many operators like $validate, and future ones like $externalFunctions, $https that have `onError : [dlq, ignore, fail]` type functionality, or `validationAction : [discard, dlq]`. 

During createStreamProcessor the pipeline should be validated to check if a DLQ has been passed in the create command against if any of the pipeline is configured to use a DLQ. If an operator is configured to use a DLQ but a DLQ is not passed at create the processor should fail to create and a error message telling the user which operator is requiring a DLQ provided.