Github user albertshau commented on a diff in the pull request:
https://github.com/apache/twill/pull/16#discussion_r90151909
--- Diff:
twill-core/src/main/java/org/apache/twill/kafka/client/KafkaConsumer.java ---
@@ -35,8 +35,10 @@
* Invoked when new messages is available.
* @param messages Iterator of new messages. The {@link
FetchedMessage} instance maybe reused in the Iterator
* and across different invocation.
+ * @return A long larger than zero as the offset to restart fetching
messages when offset error is caught,
+ * {@code -1} if the error cannot be resolved. Returns {@code
0} if no need to restart fetching.
*/
- void onReceived(Iterator<FetchedMessage> messages);
+ long onReceived(Iterator<FetchedMessage> messages);
--- End diff --
-1 for latest and -2 for earliest seems to make sense. 0 is a valid kafka
offset, though I suppose practically speaking, any use of 0 could be replaced
by -2.
It is unclear what an 'error' means. Does it mean the consumer should stop
consuming? I think we can just leave that out.
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