[GitHub] [pulsar] Anonymitaet commented on a change in pull request #4677: Blog of 2.4.0 release

[GitBox <gi...@apache.org>]

Anonymitaet commented on a change in pull request #4677: Blog of 2.4.0 release
URL: https://github.com/apache/pulsar/pull/4677#discussion_r300970260
 
 

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 File path: site2/website/blog/2019-07-05-Apache-Pulsar-2-4-0.md
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+---
+author: Penghui Li
+authorURL: https://twitter.com/lipenghui6
+title: Apache Pulsar 2.4.0
+---
+
+We are glad to present the new 2.4.0 release of Pulsar. This is the result of a huge 
+effort from the community, with over 460 commits and a long list of new features, 
+general improvements and bug fixes.
+
+Check out the <b>[release notes](/release-notes/#2.4.0)</b> for a detailed list of 
+the changes, with links to the relevant pull-requests, discussions and documentation.
+
+Regarding new features introduced, I just want to highlight here a tiny subset of them:
+
+<!--truncate-->
+
+### Delayed message delivery
+
+It's now possible to send delayed message by pulsar producer, and delayed message will 
+available after delay time.
+
+The Java code for a client using delayed message delivery will look like:
+
+```java
+producer.newMessage().value("delayed message").deliverAfter(10, TimeUnit.SECONDS).send()
+```
+
+> Note:
+>
+> 1. Messages are only delayed on shared subscriptions. Other subscriptions will deliver immediately.
+> 2. Can't work well with batching messages while messages has different delay time.
+
+### Go functions
+
+Before 2.4.0, pulsar support use Java/Python to write pulsar functions. Now, it's 
+possible to use golang to write pulsar functions, the following is an example of 
+a Pulsar Function written in golang.
+
+```go
+import (
+    "fmt"
+    "context"
+
+    "github.com/apache/pulsar/pulsar-function-go/pf"
+)
+
+func HandleRequest(ctx context.Context, in []byte) error {
+    fmt.Println(string(in) + "!")
+    return nil
+}
+
+func main() {
+    pf.Start(HandleRequest)
+}
+```
+
+### Key_shared subscription
+
+A new subscribe type `Key_shared`. By `Key_shared` one partition could have several 
+consumers to parallel consume messages, while all messages with the same key will be 
+dispatched to only one consumer ordered. 
+Here is [architecture](http://pulsar.apache.org/docs/en/concepts-messaging/#key_shared) 
+for Key_Shared.
+
+The following is an example to use `Key_shared` subscription:
+
+```java
+client.newConsumer()
+        .topic("topic")
+        .subscriptionType(SubscriptionType.Key_Shared)
+        .subscriptionName("sub-1")
+        .subscribe();
+```
+
+### Schema versioning
+
+Before 2.4.0, avro schema is using one schema for both its writer schema and reader schema. 
+Multiple schema version is support now.
+
+Use multiple schema, producer can send messages with different schema version and consumer 
+can read messages with different schema.
+
+In 2.4.0, added `FORWARD_TRANSITIVE`, `BACKWARD_TRANSITIVE` and `FULL_TRANSITIVE` compatibility 
+strategy to  check the compatibility with all existing schema version.
+
+### Replicated subscription
+
+In 2.4.0, added a mechanism to keep subscription state in-sync, within a sub-second timeframe, 
+in the context of a topic that is being asynchronously replicated across multiple geographical 
+regions. Here is [architecture](https://github.com/apache/pulsar/wiki/PIP-33%3A-Replicated-subscriptions) 
+for replicated subscription.
+
+The following is an example to use replicated subscription:
+
+```java
+Consumer<String> consumer = client.newConsumer(Schema.STRING)
+            .topic("my-topic")
+            .subscriptionName("my-subscription")
+            .replicateSubscriptionState(true)
+            .subscribe();
+```
+
+### New IO connectors
+
+A new batch of connectors was added, including Flume, Redis sink, Solr sink, RabbitMQ sink, 
+InfluxDB sink. Here is list of builtin [connectors](http://pulsar.apache.org/docs/en/io-connectors/) 
+that pulsar already supported now.
+
+### Security
+
+In 2.4.0, added support Kerberos in pulsar broker and client. 
+Following the [document](http://pulsar.apache.org/docs/en/security-kerberos/) to enable Kerberos authentication.
+
+## Conclusion
+
+Please [download](/download) Pulsar 2.4.0 and report feedback, issues or any comment into our mailing lists,
 
 Review comment:
   ```suggestion
   If you want to download Pulsar 2.4.0, click [here](https://pulsar.apache.org/en/download/).
   You can send any questions or suggestions to our mailing lists, contribute to Pulsar on [GitHub](https://github.com/apache/pulsar) or join the Apache Pulsar community on [Slack](https://apache-pulsar.herokuapp.com/).
   ```

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