[GitHub] [kafka] dengziming commented on a change in pull request #10142: KAFKA-12294: forward auto topic request within envelope on behalf of clients

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

dengziming commented on a change in pull request #10142:
URL: https://github.com/apache/kafka/pull/10142#discussion_r606613914



##########
File path: core/src/main/scala/kafka/server/AutoTopicCreationManager.scala
##########
@@ -156,17 +169,44 @@ class DefaultAutoTopicCreationManager(
         .setTopics(topicsToCreate)
     )
 
-    channelManager.get.sendRequest(createTopicsRequest, new ControllerRequestCompletionHandler {
+    val requestCompletionHandler = new ControllerRequestCompletionHandler {
       override def onTimeout(): Unit = {
         debug(s"Auto topic creation timed out for ${creatableTopics.keys}.")
         clearInflightRequests(creatableTopics)
       }
 
       override def onComplete(response: ClientResponse): Unit = {
-        debug(s"Auto topic creation completed for ${creatableTopics.keys}.")
+        debug(s"Auto topic creation completed for ${creatableTopics.keys} with response ${response.responseBody.toString}.")
         clearInflightRequests(creatableTopics)
       }
-    })
+    }
+
+    val channelManager = this.channelManager.getOrElse {
+      throw new IllegalStateException("Channel manager must be defined in order to send CreateTopic requests.")
+    }
+
+    val request = metadataRequestContext.map { context =>
+      val requestVersion =
+        channelManager.controllerApiVersions() match {
+          case None =>
+            // We will rely on the Metadata request to be retried in the case
+            // that the latest version is not usable by the controller.
+            ApiKeys.CREATE_TOPICS.latestVersion()
+          case Some(nodeApiVersions) =>
+            nodeApiVersions.latestUsableVersion(ApiKeys.CREATE_TOPICS)
+        }
+
+      // Borrow client information such as client id and correlation id from the original request,
+      // in order to correlate the create request with the original metadata request.
+      val requestHeader = new RequestHeader(ApiKeys.CREATE_TOPICS,
+        requestVersion,
+        context.clientId,
+        context.correlationId)
+      ForwardingManager.buildEnvelopeRequest(context,
+        createTopicsRequest.build(requestVersion).serializeWithHeader(requestHeader))

Review comment:
       How about moving `serializeWithHeader` to `RequestContext`, like this:
   RequestContext.java
   ```java
       public ByteBuffer buildRequestEnvelopePayload(ApiKeys apiKeys, short apiVersion, AbstractRequest body) {
           // Borrow client information such as client id and correlation id from the original request,
           // in order to correlate the create request with the original metadata request.
           RequestHeader requestHeader = new RequestHeader(apiKeys,
               apiVersion,
               clientId(),
               correlationId());
           return body.serializeWithHeader(requestHeader);
       }
   ```
   and we can call it like `context.buildRequestEnvelopePayload(ApiKeys.CREATE_TOPICS, requestVersion, createTopicsRequest.build(requestVersion))`.
   
   This trivial change has 2 benefits:
   1. Keep the symmetry of `RequestContext` since it already has a `buildResponseEnvelopePayload` method
   2. `buildRequestEnvelopePayload` can be reused in the future if we want to forward other client requests to the controller
   
   Please feel free to point my fault if I made any mistakes.




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