This is an automated email from the ASF dual-hosted git repository.
penghui pushed a commit to branch master
in repository https://gitbox.apache.org/repos/asf/pulsar.git
The following commit(s) were added to refs/heads/master by this push:
new cecffa3 [Doc]--Add Retry letter topic (#7257)
cecffa3 is described below
commit cecffa3f2a077d6f33aff2ced2a95db5316601ee
Author: HuanliMeng <[email protected]>
AuthorDate: Tue Jun 16 08:57:41 2020 +0800
[Doc]--Add Retry letter topic (#7257)
### Motivation
This PR is to update doc for the PR:
https://github.com/apache/pulsar/pull/6449
Doc contents have been approved by the previous PR
https://github.com/apache/pulsar/pull/7151.
Because there are two many conflicts in that PR. So I close the original PR
and re-create this PR.
### Modifications
Add retry letter topic in concept> messaging doc.
---
site2/docs/concepts-messaging.md | 23 +++++++++++++++++++++++
1 file changed, 23 insertions(+)
diff --git a/site2/docs/concepts-messaging.md b/site2/docs/concepts-messaging.md
index 5805971..e45800f 100644
--- a/site2/docs/concepts-messaging.md
+++ b/site2/docs/concepts-messaging.md
@@ -160,6 +160,29 @@ Dead letter topic depends on message re-delivery. Messages
are redelivered eithe
> Note
> Currently, dead letter topic is enabled only in the shared subscription mode.
+### Retry letter topic
+
+For many online business systems, a message needs to be re-consumed because
any exception occurs in the business logic processing. Generally, users hope
that they can flexibly configure the delay time for re-consuming the failed
messages. In this case, you can configure the producer to send messages to both
the business topic and the retry letter topic and you can enable automatic
retry on the consumer. When automatic retry is enabled on the consumer, a
message is stored in the retry let [...]
+
+By default, automatic retry is disabled. You can set `enableRetry` to `true`
to enable automatic retry on the consumer.
+
+This example shows how to consumer messages from a retry letter topic.
+
+```java
+Consumer<byte[]> consumer = pulsarClient.newConsumer(Schema.BYTES)
+ .topic(topic)
+ .subscriptionName("my-subscription")
+ .subscriptionType(SubscriptionType.Shared)
+ .enableRetry(true)
+ .receiverQueueSize(100)
+ .deadLetterPolicy(DeadLetterPolicy.builder()
+ .maxRedeliverCount(maxRedeliveryCount)
+
.retryLetterTopic("persistent://my-property/my-ns/my-subscription-custom-Retry")
+ .build())
+
.subscriptionInitialPosition(SubscriptionInitialPosition.Earliest)
+ .subscribe();
+```
+
## Topics
As in other pub-sub systems, topics in Pulsar are named channels for
transmitting messages from [producers](reference-terminology.md#producer) to
[consumers](reference-terminology.md#consumer). Topic names are URLs that have
a well-defined structure:
