THIS IS A TEST INSTANCE. ALL YOUR CHANGES WILL BE LOST!!!!
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1. Wire Protocol Extensions
Overview
For each type of Admin Request a separate type of Wire protocol message is created.
It is proposed to add / modify these 3 types of requests:
- Topic commands which include
CreateTopic(Request | Response),AlterTopic,DeleteTopic,DescribeTopic,ListTopics. - Replication tools -
ReassingPartition,PreferredReplicaLeaderElectionPreferredReplicaLeaderElection - Extend
TopicMetadataRequestto include topic configuration, and partition fetch lag per replica
Please find details under specific RQ/RP schema proposal.
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CreateTopicResponse => [TopicName ErrorCode]ErrorCode => int16TopicName => string |
CreateTopicResponse contains a map between topic and topic creation result error code (see New Protocol Errors).
Alter Topic Request
AlterTopicRequest => [TopicName Partitions ReplicaAssignment [AddedConfigEntry] [DeletedConfig]]TopicName => string Partitions => int32ReplicaAssignment => [PartitionId [ReplicaId]]AddedConfigEntry => ConfigKey ConfigValue ConfigKey => string ConfigValue => string DeletedConfig => string |
AlterTopicRequest is similar to previous, to specify topic level settings that should be removed, use DeletedConfig array (just setting keys). User can provide new partitions value, replica assignment or both.AlterTopicRequest contains an optional field Partitions. A special value -1 should be used to denote an empty value. The Partitions/ReplicaAssignment semantics is the following:
1) Partitions is used only to increase number of topic partitions
2) If Partitions value is empty (-1) ReplicaAssignment is not taken into account, topic partitions are not increased
3) If Partitions doesn't increase existing number of partitions an error code DecreasePartitionsNotAllowed is returned
3) If Partitions value is not empty and increases number of existing partitions, a new replica assignment for topic partitions is either automatically generated or defined by ReplicaAssignment (if nonempty)
Alter Topic Response
ErrorCode => int16TopicName => string |
AlterTopicResponse is similar to CreateTopicResponse.Delete Topic Request
DeleteTopicRequest => [TopicName]TopicName => string |
DeleteTopicRequest requires only topic names which should be deleted.Delete Topic Response
ErrorCode => int16TopicName => string |
DeleteTopicResponse is similar to CreateTopicResponse.
Topic Metadata Request V1
TopicMetadataRequest-V1 is an evolved version of TopicMetadataRequest. This request is intended to support two admin operations - describe topic information, and check whether some particular admin command (which are designed as asynchronous) has been completed. The new version of TopicMetadataResponse will include in addition topic level configuration for each topic and replica fetch lag per partition - how far partition replica is behind from the leader broker.
TopicMetadataReqeust_V1 |
DescribeTopicRequest is intended to replace TopicMetadataRequest in future versions.
DescribeTopicRequest => [TopicName]TopicName => string |
DescribeTopicRequest TopicMetadataReqeust_V1 requires only topic names. Describe Topic Response
As with the first version, an empty topic name set results in returning information for all existing topics.
Topic Metadata Response V1
DescribeTopicResponse TopicMetadataResponse_V1 => ErrorCode => int16[Broker][TopicMetadata]Broker => NodeId Host Port (any number of brokers may be returned)NodeId => int32Host => stringPort => int32TopicMetadata => TopicErrorCode TopicName [PartitionMetadata] [ConfigEntry]TopicErrorCode => int16 PartitionMetadata => PartitionErrorCode PartitionId Leader ReplicasLag IsrPartitionErrorCode => int16PartitionId => int32Leader => int32ReplicasLag => [int32 int32]Isr => [int32] |
DescribeTopicResponse TopicMetadataResponse_V1 besides errorCode which is used in the same way as in previous messages, holds optional (non empty if execution was successful) TopicDescription structure per topic. See table below for details:
Field | Description |
|---|---|
TopicConfigDetails | A structure that holds basic replication details. |
ConfigEntry | Topic-level setting and value which was overridden. |
TopicPartitionDetails | List describing replication details for each partition. |
PartitionId | Id of the partition. |
| Leader | Broker-leader id for the described partition (or -1 if not defined). |
| ReplicasReplicasLag | List of broker ids serving a replica's role for the partition . |
| ISR | Same as replicas but includes only brokers that are known to be "in-sync" |
In case of error TopicDescription field will be returned in response with default values.
List Topics Request
ListTopicsRequest => |
ListTopicsRequest is a request with no arguments.List Topics Response
| and fetch lag for the replica. | |
| ISR | Same as replicas but includes only brokers that are known to be "in-sync" |
In case of error TopicDescription field will be returned in response with default values.
Replication Commands Schema
ListTopicsResponse => ErrorCode [TopicName] ErrorCode => int16TopicName => string |
ListTopicsResponse besides errorCode holds a list of topics in Kafka cluster.
Replication Commands Schema
Reassign Partitions
Reassign Partitions Request
ReassignPartitionRequest => [Topic [PartitionId [ReplicaId]]]Topic => stringPartitionId => int32ReplicaId => int32 |
ReassignPartitionsRequest requires partition assignment - partition to array of replicas mapping. Validation for partition / replicas existence is done on server.
Reassign Partitions Response
ReassignPartitionResponse => [Topic ErrorCode]Topic => stringErrorCode => int32 |
ReassignPartitionResponse holds an error code per topic, non-empty if reassignment may not be started (e.g. due to validation error).
Reassignment status can be checked with DescribeTopicRequest field AssignedReplicas.
Preferred Replica Leader Election Request
PreferredReplicaLeaderElectionRequest => [Topic [PartitionId]]Topic => stringPartitionId => int32 |
PreferredReplicaLeaderEleactionRequest initiates preferred replica leader election procedure, similar to ReassignPartitionsRequest this request in intended to be non-blocking. The schema consist of one field - array of partitions for which preferred replica leader should be elected.To start preferred replica leader election procedure for all existing partition an empty partitions array should be sent.
Preferred Replica Leader Election Response
PreferredReplicaLeaderElectionResponse => [Topic ErrorCode]Topic => stringErrorCode => int16 |
PreferredReplicaLeaderElectionResponse is similar to ReassignPartitionsResponse.
Status of the procedure may be checked with DescribeTopicRequest TopicMetadataRequest - the head of replicas list field and leader broker should be the same.
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