[kafka] YT-21805: Introduce group coordinator

* Changelog entry
Type: feature
Component: kafka-proxy

Introduce group coordinator implementation.
commit_hash:c1e12d85f566a68e2300d2a9e0395e6a9a29ed1e

3 files changed, 32 insertions, 55 deletions

diff --git a/yt/yt/client/kafka/error.h b/yt/yt/client/kafka/error.h
index 7157740a4e..e58a67df00 100644
--- a/yt/yt/client/kafka/error.h
+++ b/yt/yt/client/kafka/error.h
@@ -9,6 +9,10 @@ namespace NYT::NKafka {
 DEFINE_ENUM_WITH_UNDERLYING_TYPE(EErrorCode, i16,
     ((UnknownServerError)           (-1))
     ((None)                         (0))
+    ((NotCoordinator)               (16))
+    ((IllegalGeneration)            (22))
+    ((InconsistentGroupProtocol)    (23))
+    ((RebalanceInProgress)          (27))
     ((TopicAuthorizationFailed)     (29))
     ((GroupAuthorizationFailed)     (30))
     ((SaslAuthenticationFailed)     (31))
diff --git a/yt/yt/client/kafka/requests.cpp b/yt/yt/client/kafka/requests.cpp
index 3b13d41459..19a3645efc 100644
--- a/yt/yt/client/kafka/requests.cpp
+++ b/yt/yt/client/kafka/requests.cpp
@@ -373,10 +373,8 @@ void TReqJoinGroup::Deserialize(IKafkaProtocolReader* reader, int apiVersion)
     SessionTimeoutMs = reader->ReadInt32();
     MemberId = reader->ReadString();
     ProtocolType = reader->ReadString();
-    Protocols.resize(reader->ReadInt32());
-    for (auto& protocol : Protocols) {
-        protocol.Deserialize(reader, apiVersion);
-    }
+
+    NKafka::Deserialize(Protocols, reader, /*isCompact*/ false, apiVersion);
 }
 
 void TRspJoinGroupMember::Serialize(IKafkaProtocolWriter* writer, int /*apiVersion*/) const
@@ -393,10 +391,7 @@ void TRspJoinGroup::Serialize(IKafkaProtocolWriter* writer, int apiVersion) cons
     writer->WriteString(Leader);
     writer->WriteString(MemberId);
 
-    writer->WriteInt32(Members.size());
-    for (const auto& member : Members) {
-        member.Serialize(writer, apiVersion);
-    }
+    NKafka::Serialize(Members, writer, /*isCompact*/ false, apiVersion);
 }
 
 ////////////////////////////////////////////////////////////////////////////////
@@ -410,36 +405,16 @@ void TReqSyncGroupAssignment::Deserialize(IKafkaProtocolReader* reader, int /*ap
 void TReqSyncGroup::Deserialize(IKafkaProtocolReader* reader, int apiVersion)
 {
     GroupId = reader->ReadString();
-    GenerationId = reader->ReadString();
+    GenerationId = reader->ReadInt32();
     MemberId = reader->ReadString();
-    Assignments.resize(reader->ReadInt32());
-    for (auto& assignment : Assignments) {
-        assignment.Deserialize(reader, apiVersion);
-    }
-}
 
-void TRspSyncGroupAssignment::Serialize(IKafkaProtocolWriter* writer, int /*apiVersion*/) const
-{
-    writer->WriteString(Topic);
-    writer->WriteInt32(Partitions.size());
-    for (const auto& partition : Partitions) {
-        writer->WriteInt32(partition);
-    }
+    NKafka::Deserialize(Assignments, reader, /*isCompact*/ false, apiVersion);
 }
 
-void TRspSyncGroup::Serialize(IKafkaProtocolWriter* writer, int apiVersion) const
+void TRspSyncGroup::Serialize(IKafkaProtocolWriter* writer, int /*apiVersion*/) const
 {
     writer->WriteErrorCode(ErrorCode);
-
-    writer->StartBytes();
-    writer->WriteInt16(0);
-    writer->WriteInt32(Assignments.size());
-    for (const auto& assignment : Assignments) {
-        assignment.Serialize(writer, apiVersion);
-    }
-    // User data.
-    writer->WriteBytes(TString{});
-    writer->FinishBytes();
+    writer->WriteBytes(Assignment);
 }
 
 ////////////////////////////////////////////////////////////////////////////////
diff --git a/yt/yt/client/kafka/requests.h b/yt/yt/client/kafka/requests.h
index faf9be8542..e727eb76d3 100644
--- a/yt/yt/client/kafka/requests.h
+++ b/yt/yt/client/kafka/requests.h
@@ -10,6 +10,11 @@ namespace NYT::NKafka {
 
 ////////////////////////////////////////////////////////////////////////////////
 
+using TMemberId = TString;
+using TGroupId = TString;
+
+////////////////////////////////////////////////////////////////////////////////
+
 DEFINE_ENUM(ERequestType,
     ((None)               (-1))
     ((Produce)            (0))
@@ -20,9 +25,10 @@ DEFINE_ENUM(ERequestType,
     ((OffsetCommit)       (8))
     ((OffsetFetch)        (9))
     ((FindCoordinator)    (10))
-    ((JoinGroup)          (11)) // Unimplemented.
-    ((Heartbeat)          (12)) // Unimplemented.
-    ((SyncGroup)          (14)) // Unimplemented.
+    ((JoinGroup)          (11))
+    ((Heartbeat)          (12))
+    ((LeaveGroup)         (13))
+    ((SyncGroup)          (14))
     ((DescribeGroups)     (15)) // Unimplemented.
     ((SaslHandshake)      (17))
     ((ApiVersions)        (18))
@@ -259,7 +265,7 @@ struct TRspFindCoordinator
 struct TReqJoinGroupProtocol
 {
     TString Name;
-    TString Metadata; // TODO(nadya73): bytes.
+    TString Metadata;
 
     void Deserialize(IKafkaProtocolReader* reader, int apiVersion);
 };
@@ -268,9 +274,9 @@ struct TReqJoinGroup
 {
     static constexpr ERequestType RequestType = ERequestType::JoinGroup;
 
-    TString GroupId;
+    TGroupId GroupId;
     i32 SessionTimeoutMs = 0;
-    TString MemberId;
+    TMemberId MemberId;
     TString ProtocolType;
     std::vector<TReqJoinGroupProtocol> Protocols;
 
@@ -279,7 +285,7 @@ struct TReqJoinGroup
 
 struct TRspJoinGroupMember
 {
-    TString MemberId;
+    TMemberId MemberId;
     TString Metadata; // TODO(nadya73): bytes.
 
     void Serialize(IKafkaProtocolWriter* writer, int apiVersion) const;
@@ -291,7 +297,7 @@ struct TRspJoinGroup
     i32 GenerationId = 0;
     TString ProtocolName;
     TString Leader;
-    TString MemberId;
+    TMemberId MemberId;
     std::vector<TRspJoinGroupMember> Members;
 
     void Serialize(IKafkaProtocolWriter* writer, int apiVersion) const;
@@ -301,7 +307,7 @@ struct TRspJoinGroup
 
 struct TReqSyncGroupAssignment
 {
-    TString MemberId;
+    TMemberId MemberId;
     TString Assignment;
 
     void Deserialize(IKafkaProtocolReader* reader, int apiVersion);
@@ -311,26 +317,18 @@ struct TReqSyncGroup
 {
     static constexpr ERequestType RequestType = ERequestType::SyncGroup;
 
-    TString GroupId;
-    TString GenerationId;
-    TString MemberId;
+    TGroupId GroupId;
+    i32 GenerationId = 0;
+    TMemberId MemberId;
     std::vector<TReqSyncGroupAssignment> Assignments;
 
     void Deserialize(IKafkaProtocolReader* reader, int apiVersion);
 };
 
-struct TRspSyncGroupAssignment
-{
-    TString Topic;
-    std::vector<i32> Partitions;
-
-    void Serialize(IKafkaProtocolWriter* writer, int apiVersion) const;
-};
-
 struct TRspSyncGroup
 {
     NKafka::EErrorCode ErrorCode = NKafka::EErrorCode::None;
-    std::vector<TRspSyncGroupAssignment> Assignments;
+    TString Assignment;
 
     void Serialize(IKafkaProtocolWriter* writer, int apiVersion) const;
 };
@@ -341,9 +339,9 @@ struct TReqHeartbeat
 {
     static constexpr ERequestType RequestType = ERequestType::Heartbeat;
 
-    TString GroupId;
+    TGroupId GroupId;
     i32 GenerationId = 0;
-    TString MemberId;
+    TMemberId MemberId;
 
     void Deserialize(IKafkaProtocolReader* reader, int apiVersion);
 };