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Code Block
  "apiKey": 18,
  "type": "response",
  "name": "ApiVersionsResponse",
  // Version 1 adds throttle time to the response.
  // Starting in version 2, on quota violation, brokers send out responses before throttling.
  // Version 3 is the first flexible version. Tagged fields are only supported in the body but
  // not in the header. The length of the header must not change in order to guarantee the
  // backward compatibility.
  // Starting from Apache Kafka 2.4, ApiKeys field is populated with the supported versions of
  // the ApiVersionsRequest when an UNSUPPORTED_VERSION error is returned.
  "validVersions": "0-3",
  "flexibleVersions": "3+",
  "fields": [
    { "name": "ErrorCode", "type": "int16", "versions": "0+",
      "about": "The top-level error code." },
    { "name": "ApiKeys", "type": "[]ApiVersionsResponseKey", "versions": "0+",
      "about": "The APIs supported by the broker.", "fields": [
      { "name": "Index", "type": "int16", "versions": "0+", "mapKey": true,
        "about": "The API index." },
      { "name": "MinVersion", "type": "int16", "versions": "0+",
        "about": "The minimum supported version, inclusive." },
      { "name": "MaxVersion", "type": "int16", "versions": "0+",
        "about": "The maximum supported version, inclusive." }
    { "name": "ThrottleTimeMs", "type": "int32", "versions": "1+", "ignorable": true,
      "about": "The duration in milliseconds for which the request was throttled due to a quota violation, or zero if the request did not violate any quota." }


We will add


a new metric in the


Selector to surface information about the connected clients.


 The mbean will be:

Code Block


The clients connected to the broker where each Map represents a connection with the following metadata:

  • ClientId
  • ClientSoftwareName
  • ClientSoftwareVersion
  • ClientAddress
  • Principal
  • Listener
  • SecurityProtocol



It will contain a single value name "connections". This will contain the number of currently open connections using the given client software name and version. If the number of connections drops to 0, the mbean will be removed.

A typical example of how this will look:

Code Block

Request Log

While the Request Log is not a public interface, it is worth mentioning that we will enrich it with the ClientSoftwareName and the ClientSoftwareVersionclient information.

Code Block
[2019-07-02 14:11:16,137] DEBUG Completed request:RequestHeader(apiKey=FIND_COORDINATOR, apiVersion=2, clientId=consumer-1, correlationId=11) -- {coordinator_key=console-consumer-17661,coordinator_type=0},response:{throttle_time_ms=0,error_code=15,error_message=null,coordinator={node_id=-1,host=,port=-1}} from connection;totalTime:3.187,requestQueueTime:0.137,localTime:2.899,remoteTime:0.0,throttleTime:0.098,responseQueueTime:0.048,sendTime:0.124,securityProtocol:PLAINTEXT,principal:User:ANONYMOUS,listener:PLAINTEXT,clientSoftwareName:java,clientSoftwareVersion:2.2.0 clientInformation:ClientInformation(softwareName=apache-kafka-java, softwareVersion=2.4.0)(kafka.request.logger)

Proposed Changes