Home > kafka-uroboros > AsyncRetryConsumer > eachBatch
Wraps the provided handler with a handler that will provide some extra callback functions for dealing with message processing errors and retries. 🚨 **Important** 🚨 Like the KafkaJS docs mention, using eachBatch directly is considered a "more advanced use case" and it is recommended that you use the eachMessage approach unless there is a specific reason that mode of processing is not workable. While the implementation inside this module is a lot more complex for the eachBatch processing model than eachMessage, the primary difference exposed to the consumer of this functionality is that instead of simply allowing exceptions to bubble up to the eachMessage wrapper function, the messageFailureHandler callback function must be used. Also, when processing retries of a message using eachBatch, some of the batch metadata provided to the eachBatch handler function will almost certainly be incorrect since the batch of messages from a retry topic may be split since some messages may not ready to be retried quite yet. When that happens, no attempt is made to keep the various attributes of the batch object (i.e. offsetLag(), offsetLagLow(), firstOffset() and lastOffset()), in sync with the actual batch of messages that are being passed to your eachBatch handler.
Signature:
eachBatch(handler: TAsyncRetryConsumerBatchHandler): EachBatchHandler;|
Parameter |
Type |
Description |
|---|---|---|
|
handler |
your batch handler that will be provided with a few extra parameters relevant to the async retry process |
EachBatchHandler
- a standard batch handler that can be passed to a KafkaJS consumer instance