[
https://issues.apache.org/jira/browse/CAMEL-16181?page=com.atlassian.jira.plugin.system.issuetabpanels:all-tabpanel
]
Javier Holguera updated CAMEL-16181:
------------------------------------
Description:
The `KafkaIdempotentRepository` initialises its cache off the back of the
pre-existing Kafka topic with previous entries, with the following code:
{code:java}
log.debug("Subscribing consumer to {}", topic);
consumer.subscribe(Collections.singleton(topic));
log.debug("Seeking to beginning");
consumer.seekToBeginning(consumer.assignment());
POLL_LOOP: while (running.get()) {
log.trace("Polling");
ConsumerRecords<String, String> consumerRecords =
consumer.poll(pollDurationMs);
if (consumerRecords.isEmpty()) {
// the first time this happens, we can assume that we have consumed all
messages up to this point
log.trace("0 messages fetched on poll");
if (cacheReadyLatch.getCount() > 0) {
log.debug("Cache warmed up");
cacheReadyLatch.countDown();
}
}{code}
The problem with this code is:
# `consumer.subscribe` doesn't instantaneously assign partitions to the
consumer
# When `consumer.seekToBeginning` is called, the operation doesn't do anything
because it has no partitions yet (see [seekToBeginning doesn't work without
auto.offset.reset
(apache.org)|https://mail-archives.apache.org/mod_mbox/kafka-users/201603.mbox/%3ccakwx9vumpliqtu9o0mpepaupszapw9lm91mwexvafwktgd3...@mail.gmail.com%3e]
# When later the first `consumer.poll` is issued, it returns nothing,
triggering the sequence to *confirm the cache as ready when it isn't yet*. That
can cause upstream messages not been correctly de-duplicated.
The solution is:
# Use a different overload of `consumer.subscribe` that accepts an
implementation of the `ConsumerRebalanceListener`.
# When partitions are assigned to the `consumer` instance, call
`seekToBeginning` there.
# Doing an initial `poll(0)` that will never return records but will force the
partition assignment process
was:
The `KafkaIdempotentRepository` initialises its cache off the back of the
pre-existing Kafka topic with previous entries, with the following code:
{code:java}
log.debug("Subscribing consumer to {}", topic);
consumer.subscribe(Collections.singleton(topic));
log.debug("Seeking to beginning");
consumer.seekToBeginning(consumer.assignment());
POLL_LOOP: while (running.get()) {
log.trace("Polling");
ConsumerRecords<String, String> consumerRecords =
consumer.poll(pollDurationMs);
if (consumerRecords.isEmpty()) {
// the first time this happens, we can assume that we have consumed all
messages up to this point
log.trace("0 messages fetched on poll");
if (cacheReadyLatch.getCount() > 0) {
log.debug("Cache warmed up");
cacheReadyLatch.countDown();
}
}{code}
\{code} The problem with this code is: # `consumer.subscribe`
doesn't instantaneously assign partitions to the consumer # When
`consumer.seekToBeginning` is called, the operation doesn't do anything because
it has no partitions yet (see [seekToBeginning doesn't work without
auto.offset.reset
(apache.org)|https://mail-archives.apache.org/mod_mbox/kafka-users/201603.mbox/%3ccakwx9vumpliqtu9o0mpepaupszapw9lm91mwexvafwktgd3...@mail.gmail.com%3e]
# When later the first `consumer.poll` is issued, it returns nothing,
triggering the sequence to *confirm the cache as ready when it isn't yet*. That
can cause upstream messages not been correctly de-duplicated. The solution
is: # Use a different overload of `consumer.subscribe` that accepts an
implementation of the `ConsumerRebalanceListener`. When partitions are assigned
to the `consumer` instance, call `seekToBeginning` there. # Doing an initial
`poll(0)` that will never return records but will force the partition
assignment process
> KafkaIdempotentRepository cache incorrectly flagged as ready
> ------------------------------------------------------------
>
> Key: CAMEL-16181
> URL: https://issues.apache.org/jira/browse/CAMEL-16181
> Project: Camel
> Issue Type: Improvement
> Components: camel-kafka
> Affects Versions: 3.7.2
> Reporter: Javier Holguera
> Priority: Major
> Fix For: 3.8.0
>
>
> The `KafkaIdempotentRepository` initialises its cache off the back of the
> pre-existing Kafka topic with previous entries, with the following code:
>
> {code:java}
> log.debug("Subscribing consumer to {}", topic);
> consumer.subscribe(Collections.singleton(topic));
> log.debug("Seeking to beginning");
> consumer.seekToBeginning(consumer.assignment());
>
> POLL_LOOP: while (running.get()) {
> log.trace("Polling");
> ConsumerRecords<String, String> consumerRecords =
> consumer.poll(pollDurationMs);
> if (consumerRecords.isEmpty()) {
> // the first time this happens, we can assume that we have consumed all
> messages up to this point
> log.trace("0 messages fetched on poll");
> if (cacheReadyLatch.getCount() > 0) {
> log.debug("Cache warmed up");
> cacheReadyLatch.countDown();
> }
> }{code}
>
> The problem with this code is:
> # `consumer.subscribe` doesn't instantaneously assign partitions to the
> consumer
> # When `consumer.seekToBeginning` is called, the operation doesn't do
> anything because it has no partitions yet (see [seekToBeginning doesn't work
> without auto.offset.reset
> (apache.org)|https://mail-archives.apache.org/mod_mbox/kafka-users/201603.mbox/%3ccakwx9vumpliqtu9o0mpepaupszapw9lm91mwexvafwktgd3...@mail.gmail.com%3e]
>
> # When later the first `consumer.poll` is issued, it returns nothing,
> triggering the sequence to *confirm the cache as ready when it isn't yet*.
> That can cause upstream messages not been correctly de-duplicated.
> The solution is:
> # Use a different overload of `consumer.subscribe` that accepts an
> implementation of the `ConsumerRebalanceListener`.
> # When partitions are assigned to the `consumer` instance, call
> `seekToBeginning` there.
> # Doing an initial `poll(0)` that will never return records but will force
> the partition assignment process
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