[Internal] Thin Client Integration: Adds thinclient mode and performance tests.

Microsoft.Azure.Cosmos/src/DocumentClient.cs

@@ -115,6 +115,10 @@ internal partial class DocumentClient : IDisposable, IAuthorizationTokenProvider
         private readonly bool IsLocalQuorumConsistency = false;
         private readonly bool isReplicaAddressValidationEnabled;
 
+        // Thin Client
+        private readonly bool isLiteClientEnabled;
+        private readonly string liteClientEndpoint;
+
         //Fault Injection
         private readonly IChaosInterceptorFactory chaosInterceptorFactory;
         private readonly IChaosInterceptor chaosInterceptor;
@@ -163,6 +167,8 @@ internal partial class DocumentClient : IDisposable, IAuthorizationTokenProvider
         private IStoreClientFactory storeClientFactory;
         internal CosmosHttpClient httpClient { get; private set; }
 
+        internal CosmosHttpClient liteModeHttpClient { get; private set; }
+
         // Flag that indicates whether store client factory must be disposed whenever client is disposed.
         // Setting this flag to false will result in store client factory not being disposed when client is disposed.
         // This flag is used to allow shared store client factory survive disposition of a document client while other clients continue using it.
@@ -194,6 +200,7 @@ internal partial class DocumentClient : IDisposable, IAuthorizationTokenProvider
         private event EventHandler<SendingRequestEventArgs> sendingRequest;
         private event EventHandler<ReceivedResponseEventArgs> receivedResponse;
         private Func<TransportClient, TransportClient> transportClientHandlerFactory;
+        private string liteClientTestEndpoint = "https://cdb-ms-stage-eastus2-fe2.eastus2.cloudapp.azure.com:10650";
 
         /// <summary>
         /// Initializes a new instance of the <see cref="DocumentClient"/> class using the
@@ -241,6 +248,12 @@ public DocumentClient(Uri serviceEndpoint,
             this.Initialize(serviceEndpoint, connectionPolicy, desiredConsistencyLevel);
             this.initTaskCache = new AsyncCacheNonBlocking<string, bool>(cancellationToken: this.cancellationTokenSource.Token);
             this.isReplicaAddressValidationEnabled = ConfigurationManager.IsReplicaAddressValidationEnabled(connectionPolicy);
+            this.isLiteClientEnabled = ConfigurationManager.IsLiteClientEnabled(defaultValue: true);
+
+            if (this.isLiteClientEnabled)
+            {
+                this.liteClientEndpoint = ConfigurationManager.GetLiteClientEndpoint(defaultValue: this.liteClientTestEndpoint);
+            }
         }
 
         /// <summary>
@@ -493,6 +506,12 @@ internal DocumentClient(Uri serviceEndpoint,
             this.initTaskCache = new AsyncCacheNonBlocking<string, bool>(cancellationToken: this.cancellationTokenSource.Token);
             this.chaosInterceptorFactory = chaosInterceptorFactory;
             this.chaosInterceptor = chaosInterceptorFactory?.CreateInterceptor(this);
+            this.isLiteClientEnabled = ConfigurationManager.IsLiteClientEnabled(defaultValue: true);
+
+            if (this.isLiteClientEnabled)
+            {
+                this.liteClientEndpoint = ConfigurationManager.GetLiteClientEndpoint(defaultValue: this.liteClientTestEndpoint);
+            }
 
             this.Initialize(
                 serviceEndpoint: serviceEndpoint,
@@ -504,7 +523,8 @@ internal DocumentClient(Uri serviceEndpoint,
                 storeClientFactory: storeClientFactory,
                 cosmosClientId: cosmosClientId,
                 remoteCertificateValidationCallback: remoteCertificateValidationCallback,
-                cosmosClientTelemetryOptions: cosmosClientTelemetryOptions);
+                cosmosClientTelemetryOptions: cosmosClientTelemetryOptions,
+                enableLiteClientMode: this.isLiteClientEnabled);
         }
 
         /// <summary>
@@ -688,7 +708,8 @@ internal virtual void Initialize(Uri serviceEndpoint,
             TokenCredential tokenCredential = null,
             string cosmosClientId = null,
             RemoteCertificateValidationCallback remoteCertificateValidationCallback = null,
-            CosmosClientTelemetryOptions cosmosClientTelemetryOptions = null)
+            CosmosClientTelemetryOptions cosmosClientTelemetryOptions = null,
+            bool enableLiteClientMode = false)
         {
             if (serviceEndpoint == null)
             {
@@ -947,6 +968,17 @@ internal virtual void Initialize(Uri serviceEndpoint,
                 this.sendingRequest,
                 this.receivedResponse);
 
+            if (enableLiteClientMode)
+            {
+                this.liteModeHttpClient = CosmosHttpClientCore.CreateWithConnectionPolicy(
+                    this.ApiType,
+                    DocumentClientEventSource.Instance,
+                    this.ConnectionPolicy,
+                    null,
+                    this.sendingRequest,
+                    this.receivedResponse);
+            }
+
             // Loading VM Information (non blocking call and initialization won't fail if this call fails)
             VmMetadataApiHandler.TryInitialize(this.httpClient);
 
@@ -1052,6 +1084,23 @@ private async Task<bool> GetInitializationTaskAsync(IStoreClientFactory storeCli
             {
                 this.StoreModel = this.GatewayStoreModel;
             }
+            // Change it to this.ConnectionPolicy.ConnectionMode == ConnectionMode.LiteClient when LiteClient is supported.
+            else if (this.isLiteClientEnabled)
+            {
+                ThinClientStoreModel thinClientStoreModel = new (
+                    endpointManager: this.GlobalEndpointManager,
+                    this.sessionContainer,
+                    (Cosmos.ConsistencyLevel)this.accountServiceConfiguration.DefaultConsistencyLevel,
+                    this.eventSource,
+                    this.serializerSettings,
+                    this.liteModeHttpClient,
+                    new Uri(this.liteClientEndpoint),
+                    this.accountServiceConfiguration.AccountProperties.Id);
+
+                thinClientStoreModel.SetCaches(this.partitionKeyRangeCache, this.collectionCache);
+
+                this.StoreModel = thinClientStoreModel;
+            }
             else
             {
                 this.InitializeDirectConnectivity(storeClientFactory);
@@ -6528,6 +6577,13 @@ internal IStoreModel GetStoreProxy(DocumentServiceRequest request)
                 return this.GatewayStoreModel;
             }
 
+            if (this.isLiteClientEnabled
+                && operationType == OperationType.Read
+                && resourceType == ResourceType.Database)
+            {
+                return this.GatewayStoreModel;
+            }
+
             if (operationType == OperationType.Create
                 || operationType == OperationType.Upsert)
             {

Microsoft.Azure.Cosmos/src/HttpClient/CosmosHttpClientCore.cs

@@ -441,7 +441,7 @@ private static bool IsOutOfRetries(
             return !timeoutEnumerator.MoveNext(); // No more retries are configured
         }
 
-        private async Task<HttpResponseMessage> ExecuteHttpHelperAsync(
+        public async Task<HttpResponseMessage> ExecuteHttpHelperAsync(
             HttpRequestMessage requestMessage,
             ResourceType resourceType,
             CancellationToken cancellationToken)