Add the isolation level option

Author: Hectorhammett

apis/Google.Cloud.Spanner.Data/Google.Cloud.Spanner.Data/SpannerTransactionCreationOptions.cs

@@ -14,6 +14,7 @@
 
 using Google.Api.Gax;
 using Google.Cloud.Spanner.V1;
+using System;
 using static Google.Cloud.Spanner.V1.TransactionOptions.Types;
 
 namespace Google.Cloud.Spanner.Data;
@@ -28,19 +29,19 @@ public sealed class SpannerTransactionCreationOptions
     /// Options that will result in a read-write transaction.
     /// </summary>
     public static SpannerTransactionCreationOptions ReadWrite { get; } = new SpannerTransactionCreationOptions(
-        timestampBound: null, transactionId: null, isDetached: false, isSingleUse: false, isPartitionedDml: false, excludeFromChangeStreams: false);
+        timestampBound: null, transactionId: null, isDetached: false, isSingleUse: false, isPartitionedDml: false, excludeFromChangeStreams: false, isolationLevel: IsolationLevel.Unspecified);
 
     /// <summary>
     /// Options that will result in a read-write transaction suitable for executing partioned DML.
     /// </summary>
     public static SpannerTransactionCreationOptions PartitionedDml { get; } = new SpannerTransactionCreationOptions(
-        timestampBound: null, transactionId: null, isDetached: false, isSingleUse: false, isPartitionedDml: true, excludeFromChangeStreams: false);
+        timestampBound: null, transactionId: null, isDetached: false, isSingleUse: false, isPartitionedDml: true, excludeFromChangeStreams: false, isolationLevel: IsolationLevel.Unspecified);
 
     /// <summary>
     /// Options that will result in a read-only transaction bound by <see cref="TimestampBound.Strong"/>.
     /// </summary>
     public static SpannerTransactionCreationOptions ReadOnly { get; } = new SpannerTransactionCreationOptions(
-        TimestampBound.Strong, transactionId: null, isDetached: false, isSingleUse: false, isPartitionedDml: false, excludeFromChangeStreams: false);
+        TimestampBound.Strong, transactionId: null, isDetached: false, isSingleUse: false, isPartitionedDml: false, excludeFromChangeStreams: false, isolationLevel: IsolationLevel.Unspecified);
 
     /// <summary>
     /// Timestamp bound settings for the transaction. May be null.
@@ -92,6 +93,13 @@ public sealed class SpannerTransactionCreationOptions
     /// </summary>
     public bool IsPartitionedDml { get; }
 
+    /// <summary>
+    /// Set the isolation level for the transaction. This is only meant for read-write transactions.
+    /// <see cref="TransactionOptions.Types.IsolationLevel"/> to reference the possible configuration values.
+    /// When this is set to other than ISOLATION_LEVEL_UNSPECIFIED the transaction will be read-write.
+    /// </summary>
+    public IsolationLevel IsolationLevel { get; }
+
     /// <summary>
     /// Whether changes executed within this transaction are recorded in change streams or not.
     /// This will always be false for read-only transactions.
@@ -105,7 +113,7 @@ public sealed class SpannerTransactionCreationOptions
     /// </remarks>
     public bool ExcludeFromChangeStreams { get; }
 
-    private SpannerTransactionCreationOptions(TimestampBound timestampBound, TransactionId transactionId, bool isDetached, bool isSingleUse, bool isPartitionedDml, bool excludeFromChangeStreams)
+    private SpannerTransactionCreationOptions(TimestampBound timestampBound, TransactionId transactionId, bool isDetached, bool isSingleUse, bool isPartitionedDml, bool excludeFromChangeStreams, IsolationLevel isolationLevel)
     {
         GaxPreconditions.CheckArgument(
             timestampBound is null || transactionId is null,
@@ -137,6 +145,11 @@ private SpannerTransactionCreationOptions(TimestampBound timestampBound, Transac
             nameof(excludeFromChangeStreams),
             "Only read-write and partioned DML transactions can be marked for change stream exclusion.");
         ExcludeFromChangeStreams = excludeFromChangeStreams;
+        GaxPreconditions.CheckArgument(
+            isolationLevel != IsolationLevel.Unspecified && TimestampBound == TimestampBound.Strong,
+            nameof(isolationLevel),
+            $"{nameof(isolationLevel)} cannot be set on a Read-only transaction"
+        );
     }
 
     /// <summary>
@@ -155,7 +168,8 @@ timestampBound is null
             isDetached: false,
             isSingleUse: timestampBound?.Mode == TimestampBoundMode.MinReadTimestamp || timestampBound?.Mode == TimestampBoundMode.MaxStaleness,
             isPartitionedDml: false,
-            excludeFromChangeStreams: false);
+            excludeFromChangeStreams: false,
+            isolationLevel: IsolationLevel.Unspecified);
 
     /// <summary>
     /// Creates transaction options with the given <paramref name="transactionId"/>.
@@ -170,15 +184,16 @@ public static SpannerTransactionCreationOptions FromReadOnlyTransactionId(Transa
             isDetached: true,
             isSingleUse: false,
             isPartitionedDml: false,
-            excludeFromChangeStreams: false);
+            excludeFromChangeStreams: false,
+            isolationLevel: IsolationLevel.Unspecified);
 
     /// <summary>
     /// Options used to acquire the transaction's underlying session.
     /// </summary>
     internal TransactionOptions GetTransactionOptions()
     {
-        var options = IsPartitionedDml ? new TransactionOptions { PartitionedDml = new PartitionedDml() } :
-            TransactionMode == TransactionMode.ReadWrite ? new TransactionOptions { ReadWrite = new ReadWrite() } :
+        var options = IsPartitionedDml ? new TransactionOptions { PartitionedDml = new PartitionedDml(), IsolationLevel = IsolationLevel.Unspecified } :
+            TransactionMode == TransactionMode.ReadWrite ? new TransactionOptions { ReadWrite = new ReadWrite(), IsolationLevel = IsolationLevel } :
             TimestampBound?.ToTransactionOptions();
         if (options is not null)
         {
@@ -192,7 +207,7 @@ internal TransactionOptions GetTransactionOptions()
     /// If <see cref="TransactionId"/> is set, <see cref="IsDetached"/> cannot be false.
     /// </summary>
     public SpannerTransactionCreationOptions WithIsDetached(bool isDetached) =>
-        isDetached == IsDetached ? this : new SpannerTransactionCreationOptions(TimestampBound, TransactionId, isDetached, IsSingleUse, IsPartitionedDml, ExcludeFromChangeStreams);
+        isDetached == IsDetached ? this : new SpannerTransactionCreationOptions(TimestampBound, TransactionId, isDetached, IsSingleUse, IsPartitionedDml, ExcludeFromChangeStreams, IsolationLevel);
 
     /// <summary>
     /// Returns a new instance identical to this one except for the value of <see cref="IsSingleUse"/>.
@@ -201,12 +216,18 @@ public SpannerTransactionCreationOptions WithIsDetached(bool isDetached) =>
     /// <see cref="IsSingleUse"/> cannot be false.
     /// </summary>
     public SpannerTransactionCreationOptions WithIsSingleUse(bool isSingleUse) =>
-        isSingleUse == IsSingleUse ? this : new SpannerTransactionCreationOptions(TimestampBound, TransactionId, IsDetached, isSingleUse, IsPartitionedDml, ExcludeFromChangeStreams);
+        isSingleUse == IsSingleUse ? this : new SpannerTransactionCreationOptions(TimestampBound, TransactionId, IsDetached, isSingleUse, IsPartitionedDml, ExcludeFromChangeStreams, IsolationLevel);
 
     /// <summary>
     /// Returns a new instance identical to this one except for the value of <see cref="ExcludeFromChangeStreams"/>.
     /// <see cref="ExcludeFromChangeStreams"/> can only be true for read-write transactions.
     /// </summary>
     public SpannerTransactionCreationOptions WithExcludeFromChangeStreams(bool excludeFromChangeStreams) =>
-        excludeFromChangeStreams == ExcludeFromChangeStreams ? this : new SpannerTransactionCreationOptions(TimestampBound, TransactionId, IsDetached, IsSingleUse, IsPartitionedDml, excludeFromChangeStreams);
+        excludeFromChangeStreams == ExcludeFromChangeStreams ? this : new SpannerTransactionCreationOptions(TimestampBound, TransactionId, IsDetached, IsSingleUse, IsPartitionedDml, excludeFromChangeStreams, IsolationLevel);
+
+    /// <summary>
+    /// Returns a new instance identical to this one except for the value of <see cref="IsolationLevel"/>
+    /// </summary>
+    public SpannerTransactionCreationOptions WithIsolationLevel(IsolationLevel isolationLevel) =>
+        isolationLevel == IsolationLevel ? this : new SpannerTransactionCreationOptions(TimestampBound, TransactionId, IsDetached, IsSingleUse, IsPartitionedDml, ExcludeFromChangeStreams, isolationLevel);
 }