Added DisableServerBalancer: support for server-side load balancing of sessions.

Author: LiamHamsters

src/Ydb.Sdk/CHANGELOG.md

@@ -1,3 +1,6 @@
+## v0.20.2
+- Added `DisableServerBalancer` option to ADO.NET session creation; default false.
+
 ## v0.20.1
 
 - Fixed bug ADO.NET: `YdbSchema.SchemaObjects` and `Ydb.DescribeTable`methods are public for `EntityFrameworkCore.Ydb`.

src/Ydb.Sdk/src/GrpcRequestSettings.cs

@@ -8,7 +8,7 @@ public class GrpcRequestSettings
 {
     public string TraceId { get; set; } = string.Empty;
     public TimeSpan TransportTimeout { get; set; } = TimeSpan.Zero;
-    public ImmutableArray<string> CustomClientHeaders { get; } = new();
+    public List<string> List { get; } = new();
     public CancellationToken CancellationToken = default;
 
     internal long NodeId { get; set; }

src/Ydb.Sdk/src/IDriver.cs

@@ -181,8 +181,8 @@ protected async ValueTask<CallOptions> GetCallOptions(GrpcRequestSettings settin
         {
             meta.Add(Metadata.RpcTraceIdHeader, settings.TraceId);
         }
-
-        if (!Config.DisableServerBalancer)
+        
+        if (!settings.List.Contains("session-balancer"))
         {
             meta.Add(Metadata.RpcClientCapabilitiesHeader, "session-balancer");
         }

src/Ydb.Sdk/src/Services/Sessions/SessionPoolBase.cs

@@ -16,6 +16,8 @@ public SessionPoolConfig(uint? sizeLimit = null)
     public TimeSpan PeriodicCheckInterval { get; set; } = TimeSpan.FromSeconds(10);
     public TimeSpan KeepAliveTimeout { get; set; } = TimeSpan.FromSeconds(1);
     public TimeSpan CreateSessionTimeout { get; set; } = TimeSpan.FromSeconds(1);
+    
+    public bool DisableServerBalancer { get; set; } = GrpcDefaultSettings.DisableServerBalancer;
 }
 
 public class GetSessionResponse<TSession> : ResponseWithResultBase<TSession>, IDisposable where TSession : SessionBase

src/Ydb.Sdk/src/Services/Table/SessionPool.cs

@@ -23,11 +23,18 @@ public SessionPool(Driver driver, SessionPoolConfig config) :
 
     private protected override async Task<GetSessionResponse> CreateSession()
     {
-        var createSessionResponse = await _tableClient.CreateSession(new CreateSessionSettings
+        var createSessionSettings = new CreateSessionSettings
         {
             TransportTimeout = Config.CreateSessionTimeout,
-            OperationTimeout = Config.CreateSessionTimeout
-        });
+            OperationTimeout = Config.CreateSessionTimeout,
+        };
+
+        if (!Config.DisableServerBalancer)
+        {
+            createSessionSettings.List.Add("session-balancer");
+        }
+
+        var createSessionResponse = await _tableClient.CreateSession(createSessionSettings);
 
         lock (Lock)
         {