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All Kafka APIs

BrokerHeartbeat

This page encodes the smallest legal instance of the request and the response: numeric fields are zero, strings and byte arrays are empty, every array carries exactly one sample element, and any records field holds one empty 61-byte RecordBatch v2. Version 1 is a flexible version, so every struct is terminated by a uvarint tagged-field count and strings and arrays carry compact length-plus-one prefixes. Sizes below include the leading int32 size prefix.

API key
63
Encoded at
v1
Flexible versions
0+
Headers
req v2, resp v1
Request versions
0-1
Response versions
0-1
Request size
38 bytes
Response size
19 bytes
framerpc headerrequest bodyRecordBatchRecordresponse bodytagged_fields

Request

BrokerHeartbeatRequest v1, request header v2, 38 bytes on the wire

byte layout (38 bytes, 16 bytes per row)

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object tree

BrokerHeartbeatRequest         message v1                               [0x0000, 38B]
+-- Frame                                                               [0x0000, 4B]   length-delimited framing
|   +-- size                   int32            = 34                    [0x0000, 4B]   number of bytes that follow, patched after encoding
+-- RequestHeader              v2                                       [0x0004, 11B]  common request header
|   +-- request_api_key        int16            = 63 (BrokerHeartbeat)  [0x0004, 2B]   numeric id of the API being invoked
|   +-- request_api_version    int16            = 1                     [0x0006, 2B]   version of the API being invoked
|   +-- correlation_id         int32            = 0                     [0x0008, 4B]   echoed back by the broker in the response
|   +-- client_id              nullable_string  = "" (int16 len=0)      [0x000c, 2B]   always a non-flexible int16-prefixed string
|   +-- tagged_fields          uvarint          = 0                     [0x000e, 1B]   number of tagged fields in the header
+-- BrokerHeartbeatRequest     struct                                   [0x000f, 23B]  message body, version 1
    +-- BrokerId               int32            = 0                     [0x000f, 4B]   The broker ID.
    +-- BrokerEpoch            int64            = 0                     [0x0013, 8B]   The broker epoch.
    +-- CurrentMetadataOffset  int64            = 0                     [0x001b, 8B]   The highest metadata offset which the broker has reached.
    +-- WantFence              bool             = false                 [0x0023, 1B]   True if the broker wants to be fenced, false otherwise.
    +-- WantShutDown           bool             = false                 [0x0024, 1B]   True if the broker wants to be shut down, false otherwise.
    +-- tagged_fields          uvarint          = 0                     [0x0025, 1B]   number of tagged fields in this struct

kafka message schema (.json)

{
  "apiKey": 63,
  "type": "request",
  "listeners": ["controller"],
  "name": "BrokerHeartbeatRequest",
  "validVersions": "0-1",
  "flexibleVersions": "0+",
  "fields": [
    { "name": "BrokerId", "type": "int32", "versions": "0+", "entityType": "brokerId",
      "about": "The broker ID." },
    { "name": "BrokerEpoch", "type": "int64", "versions": "0+", "default": "-1",
      "about": "The broker epoch." },
    { "name": "CurrentMetadataOffset", "type": "int64", "versions": "0+",
      "about": "The highest metadata offset which the broker has reached." },
    { "name": "WantFence", "type": "bool", "versions": "0+",
      "about": "True if the broker wants to be fenced, false otherwise." },
    { "name": "WantShutDown", "type": "bool", "versions": "0+",
      "about": "True if the broker wants to be shut down, false otherwise." },
    { "name": "OfflineLogDirs", "type":  "[]uuid", "versions": "1+", "taggedVersions": "1+", "tag": "0",
      "about": "Log directories that failed and went offline." }
  ]
}

Response

BrokerHeartbeatResponse v1, response header v1, 19 bytes on the wire

byte layout (19 bytes, 16 bytes per row)

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object tree

BrokerHeartbeatResponse      message v1           [0x0000, 19B]
+-- Frame                                         [0x0000, 4B]   length-delimited framing
|   +-- size                 int32       = 15     [0x0000, 4B]   number of bytes that follow, patched after encoding
+-- ResponseHeader           v1                   [0x0004, 5B]   common response header
|   +-- correlation_id       int32       = 0      [0x0004, 4B]   matches the correlation_id of the request
|   +-- tagged_fields        uvarint     = 0      [0x0008, 1B]   number of tagged fields in the header
+-- BrokerHeartbeatResponse  struct               [0x0009, 10B]  message body, version 1
    +-- ThrottleTimeMs       int32       = 0      [0x0009, 4B]   Duration in milliseconds for which the request was throttled due to a quota...
    +-- ErrorCode            int16       = 0      [0x000d, 2B]   The error code, or 0 if there was no error.
    +-- IsCaughtUp           bool        = false  [0x000f, 1B]   True if the broker has approximately caught up with the latest metadata.
    +-- IsFenced             bool        = false  [0x0010, 1B]   True if the broker is fenced.
    +-- ShouldShutDown       bool        = false  [0x0011, 1B]   True if the broker should proceed with its shutdown.
    +-- tagged_fields        uvarint     = 0      [0x0012, 1B]   number of tagged fields in this struct

kafka message schema (.json)

{
  "apiKey": 63,
  "type": "response",
  "name": "BrokerHeartbeatResponse",
  "validVersions": "0-1",
  "flexibleVersions": "0+",
  "fields": [
    { "name": "ThrottleTimeMs", "type": "int32", "versions": "0+",
      "about": "Duration in milliseconds for which the request was throttled due to a quota violation, or zero if the request did not violate any quota." },
    { "name": "ErrorCode", "type": "int16", "versions": "0+",
      "about": "The error code, or 0 if there was no error." },
    { "name": "IsCaughtUp", "type": "bool", "versions": "0+", "default": "false",
      "about": "True if the broker has approximately caught up with the latest metadata." },
    { "name": "IsFenced", "type": "bool", "versions": "0+", "default": "true",
      "about": "True if the broker is fenced." },
    { "name": "ShouldShutDown", "type": "bool", "versions": "0+",
      "about": "True if the broker should proceed with its shutdown." }
  ]
}