Github user ptgoetz commented on a diff in the pull request:
https://github.com/apache/storm/pull/493#discussion_r27512587
--- Diff: external/storm-kafka/README.md ---
@@ -120,6 +120,23 @@ spoutConf.scheme = new SchemeAsMultiScheme(new
StringScheme());
OpaqueTridentKafkaSpout spout = new OpaqueTridentKafkaSpout(spoutConf);
```
+### How KafkaSpout stores offsets of a kafka topic and recovers incase of
failures
+
+As shown in the above KafkaConfig properties , user can control where in
the topic they can start reading by setting **KafkaConfig.startOffsetTime.**
+
+There are two options **kafka.api.OffsetRequest.EarliestTime()** which
makes the KafkaSpout to read from the begining of the topic and
--- End diff --
I would also document the actual values of `EarliestTime()` (`-2`) and
`LatestTime()` (`-1`), and that it can also be set to a point in time (a la
`System.currentTimeMillis()`).
My reasoning behind documenting the values (as opposed to the kafka API
constants) is that the start offset time is likely to be specified via
configuration (i.e. outside java code). Either that, or add spout constants
that would get evaluated to `EarliestTime()`/`LatestTime()` if for some reason
those values were ever changed in the Kafka API -- that seems like a less
"leaky" solution.
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