feat: Adds TableBuilder, which can be used to prepopulate the internal metadata cache used by the document and object-mapper DynamoDB programming models

sdk/src/Services/DynamoDBv2/Custom/DataModel/Context.cs

@@ -53,6 +53,49 @@ public partial class DynamoDBContext : IDynamoDBContext
 
         #endregion
 
+        #region Public methods
+        /// <inheritdoc/>
+        public void RegisterTableDefinition(Table table)
+        {
+            try
+            {
+                _readerWriterLockSlim.EnterReadLock();
+
+                if (tablesMap.ContainsKey(table.TableName))
+                {
+                    return;
+                }
+            }
+            finally
+            {
+                if (_readerWriterLockSlim.IsReadLockHeld)
+                {
+                    _readerWriterLockSlim.ExitReadLock();
+                }
+            }
+
+            try
+            {
+                _readerWriterLockSlim.EnterWriteLock();
+
+                // Check to see if another thread got the write lock before this thread and filled the cache.
+                if (tablesMap.ContainsKey(table.TableName))
+                {
+                    return;
+                }
+
+                tablesMap[table.TableName] = table;
+            }
+            finally
+            {
+                if (_readerWriterLockSlim.IsWriteLockHeld)
+                {
+                    _readerWriterLockSlim.ExitWriteLock();
+                }
+            }
+        }
+        #endregion
+
         #region Constructors
 
 #if !NETSTANDARD

sdk/src/Services/DynamoDBv2/Custom/DataModel/IDynamoDBContext.cs

@@ -27,6 +27,23 @@ namespace Amazon.DynamoDBv2.DataModel
     /// </summary>
     public partial interface IDynamoDBContext : IDisposable
     {
+        #region Public methods
+        /// <summary>
+        /// Adds a <see cref="Table"/> to this context's internal cache, which
+        /// will avoid the need to fetch table metadata automatically from DynamoDB.
+        /// This may be used in conjunction with an <see cref="ITableBuilder"/>.
+        /// </summary>
+        /// <remarks>
+        /// Using this method can avoid latency and thread starvation due to blocking asynchronous 
+        /// <see cref="IAmazonDynamoDB.DescribeTable(string)"/> calls that are used to populate 
+        /// the SDK's cache of table metadata. It requires that the table's index schema described accurately, 
+        /// otherwise exceptions may be thrown and/or the results of certain DynamoDB operations may change. 
+        /// </remarks>
+        /// <param name="table">Table to add to the internal cache</param>
+        void RegisterTableDefinition(Table table);
+
+        #endregion
+
         #region Save/serialize
 
         /// <summary>

sdk/src/Services/DynamoDBv2/Custom/DocumentModel/ITableBuilder.cs

@@ -0,0 +1,69 @@
+/*
+ * Copyright Amazon.com, Inc. or its affiliates. All Rights Reserved.
+ * 
+ * Licensed under the Apache License, Version 2.0 (the "License").
+ * You may not use this file except in compliance with the License.
+ * A copy of the License is located at
+ * 
+ *  http://aws.amazon.com/apache2.0
+ * 
+ * or in the "license" file accompanying this file. This file is distributed
+ * on an "AS IS" BASIS, WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either
+ * express or implied. See the License for the specific language governing
+ * permissions and limitations under the License.
+ */
+
+namespace Amazon.DynamoDBv2.DocumentModel
+{
+    /// <summary>
+    /// Interface for a builder that constructs a <see cref="Table"/>
+    /// </summary>
+    public interface ITableBuilder
+    {
+        /// <summary>
+        /// Call at the end to retrieve the new <see cref="Table"/>
+        /// </summary>
+        /// <returns>Built table</returns>
+        Table Build();
+
+        /// <summary>
+        /// Adds the primary key definition to the table
+        /// </summary>
+        /// <param name="hashKeyAttribute">Name of the attribute used as the partition key</param>
+        /// <param name="type">Type of that attribute</param>
+        ITableBuilder AddHashKey(string hashKeyAttribute, DynamoDBEntryType type);
+
+        /// <summary>
+        /// Adds a sort key definition to the table
+        /// </summary>
+        /// <param name="rangeKeyAttribute">Name of the attribute used as the sort key</param>
+        /// <param name="type">Type of that attribute </param>
+        ITableBuilder AddRangeKey(string rangeKeyAttribute, DynamoDBEntryType type);
+
+        /// <summary>
+        /// Adds a local secondary index definition to the table
+        /// </summary>
+        /// <param name="indexName">Name of the local secondary index</param>
+        /// <param name="rangeKeyAttribute">Name of the attribute used as the sort key in the local secondary index</param>
+        /// <param name="type">Type of that attribute</param>
+        ITableBuilder AddLocalSecondaryIndex(string indexName, string rangeKeyAttribute, DynamoDBEntryType type);
+
+        /// <summary>
+        /// Adds a global secondary index definition to the table
+        /// </summary>
+        /// <param name="indexName">Name of the global secondary index</param>
+        /// <param name="hashkeyAttribute">Name of the attribute used as the partition key in the GSI</param>
+        /// <param name="hashKeyType">Type of the hash key attribute</param>
+        ITableBuilder AddGlobalSecondaryIndex(string indexName, string hashkeyAttribute, DynamoDBEntryType hashKeyType);
+
+        /// <summary>
+        /// Adds a global secondary index definition to the table
+        /// </summary>
+        /// <param name="indexName">Name of the global secondary index</param>
+        /// <param name="hashkeyAttribute">Name of the attribute used as the partition key in the GSI</param>
+        /// <param name="hashKeyType">Type of the hash key attribute</param>
+        /// <param name="rangeKeyAttribute">Name of the attribute used as the sort key in the GSI</param>
+        /// <param name="rangeKeyType">Type of the sort key attribute</param>
+        ITableBuilder AddGlobalSecondaryIndex(string indexName, string hashkeyAttribute, DynamoDBEntryType hashKeyType, string rangeKeyAttribute, DynamoDBEntryType rangeKeyType);
+    }
+}

sdk/src/Services/DynamoDBv2/Custom/DocumentModel/Table.cs

@@ -340,7 +340,7 @@ private static void ValidateConditional(IConditionalOperationConfig config)
                 throw new InvalidOperationException("Only one of the conditonal properties Expected, ExpectedState and ConditionalExpression can be set.");
         }
 
-        private void ClearTableData()
+        internal void ClearTableData()
         {
             Keys = new Dictionary<string, KeyDescription>();
             HashKeys = new List<string>();
@@ -399,7 +399,7 @@ internal Dictionary<string, AttributeValue> ToAttributeMap(Document doc, DynamoD
 
         #region Constructor/factory
 
-        private Table(IAmazonDynamoDB ddbClient, TableConfig config)
+        internal Table(IAmazonDynamoDB ddbClient, TableConfig config)
         {
             if (config == null)
                 throw new ArgumentNullException("config");