CamelExchangeException Invalid Correlation Key on exchange header - apache-camel

Question

Apache Camel is throwing Invalid Correlation Key exception when trying to aggregate messages from my AWS SQS queue.
The messages were placed in the queue using ZipSplitter and they all appear in the queue with matching "parentId" values (which I added using a random uuid as part of the splitting -I've tried CamelSourceFile as well). I get the Exception repeatedly until the retries are exhausted.
My aggregate expression:
from(--queue--).aggregate(header("parentId"), customAggregationStrategy).completionTimeout(3000).processor(new Processor() {...}.to(--next queue--);
There is no logging emitted from my customAggregationStrategy nor from any of the subsequent processors. It fails to aggregate:
... DeadLetterChannel - Failed delivery for (MessageId: ...). On Delivery attempt: 0 caught ...CamelExchangeException: Invalid correlation key. Exchange[ID...]
The delivery attempt is 0 through 9 for my retry attempts.
The infuriating thing is that the code works everywhere but locally...which you think would narrow things down, but neither the exception nor anything else logged sheds any light onto what is going on here.

Answer 1

You could try to use Camel simple language when expressing the correlation key, ie:
.aggregate(simple("${headers.parentId}", customAggregationStrategy)
This way, the exceptions might be silently ignored ?
Did you activate Camel tracer (http://camel.apache.org/tracer.html) to analyse your exchanges and ease the debugging ?
I suspect you have an Exchange which does NOT have the "parentId" header. If you want to skip them, just activate the ignoreInvalidCorrelationKeys option (see http://camel.apache.org/aggregator2.html)