chore(spanner): add multiplexed session support for batch write (#3470)

* chore(spanner): add multiplexed session support for batch write

* chore(spanner): lint fix

Author: harshachinta

google-cloud-spanner/src/main/java/com/google/cloud/spanner/AbstractMultiplexedSessionDatabaseClient.java

@@ -16,10 +16,7 @@
 
 package com.google.cloud.spanner;
 
-import com.google.api.gax.rpc.ServerStream;
 import com.google.cloud.Timestamp;
-import com.google.cloud.spanner.Options.TransactionOption;
-import com.google.spanner.v1.BatchWriteResponse;
 
 /**
  * Base class for the Multiplexed Session {@link DatabaseClient} implementation. Throws {@link
@@ -43,11 +40,4 @@ public String getDatabaseRole() {
   public Timestamp writeAtLeastOnce(Iterable<Mutation> mutations) throws SpannerException {
     return writeAtLeastOnceWithOptions(mutations).getCommitTimestamp();
   }
-
-  @Override
-  public ServerStream<BatchWriteResponse> batchWriteAtLeastOnce(
-      Iterable<MutationGroup> mutationGroups, TransactionOption... options)
-      throws SpannerException {
-    throw new UnsupportedOperationException();
-  }
 }

google-cloud-spanner/src/main/java/com/google/cloud/spanner/DatabaseClientImpl.java

@@ -189,6 +189,9 @@ public ServerStream<BatchWriteResponse> batchWriteAtLeastOnce(
       throws SpannerException {
     ISpan span = tracer.spanBuilder(READ_WRITE_TRANSACTION, commonAttributes, options);
     try (IScope s = tracer.withSpan(span)) {
+      if (canUseMultiplexedSessionsForRW() && getMultiplexedSessionDatabaseClient() != null) {
+        return getMultiplexedSessionDatabaseClient().batchWriteAtLeastOnce(mutationGroups, options);
+      }
       return runWithSessionRetry(session -> session.batchWriteAtLeastOnce(mutationGroups, options));
     } catch (RuntimeException e) {
       span.setStatus(e);

google-cloud-spanner/src/main/java/com/google/cloud/spanner/DelayedMultiplexedSessionTransaction.java

@@ -20,12 +20,14 @@
 
 import com.google.api.core.ApiFuture;
 import com.google.api.core.ApiFutures;
+import com.google.api.gax.rpc.ServerStream;
 import com.google.cloud.Timestamp;
 import com.google.cloud.spanner.DelayedReadContext.DelayedReadOnlyTransaction;
 import com.google.cloud.spanner.MultiplexedSessionDatabaseClient.MultiplexedSessionTransaction;
 import com.google.cloud.spanner.Options.TransactionOption;
 import com.google.cloud.spanner.Options.UpdateOption;
 import com.google.common.util.concurrent.MoreExecutors;
+import com.google.spanner.v1.BatchWriteResponse;
 import java.util.concurrent.ExecutionException;
 
 /**
@@ -164,6 +166,22 @@ public CommitResponse writeWithOptions(Iterable<Mutation> mutations, Transaction
     }
   }
 
+  /**
+   * This is a blocking method, as the interface that it implements is also defined as a blocking
+   * method.
+   */
+  @Override
+  public ServerStream<BatchWriteResponse> batchWriteAtLeastOnce(
+      Iterable<MutationGroup> mutationGroups, TransactionOption... options)
+      throws SpannerException {
+    SessionReference sessionReference = getSessionReference();
+    try (MultiplexedSessionTransaction transaction =
+        new MultiplexedSessionTransaction(
+            client, span, sessionReference, NO_CHANNEL_HINT, /* singleUse = */ true)) {
+      return transaction.batchWriteAtLeastOnce(mutationGroups, options);
+    }
+  }
+
   @Override
   public TransactionRunner readWriteTransaction(TransactionOption... options) {
     return new DelayedTransactionRunner(

google-cloud-spanner/src/main/java/com/google/cloud/spanner/MultiplexedSessionDatabaseClient.java

@@ -22,6 +22,7 @@
 import com.google.api.core.ApiFuture;
 import com.google.api.core.ApiFutures;
 import com.google.api.core.SettableApiFuture;
+import com.google.api.gax.rpc.ServerStream;
 import com.google.cloud.Timestamp;
 import com.google.cloud.spanner.Options.TransactionOption;
 import com.google.cloud.spanner.Options.UpdateOption;
@@ -30,6 +31,7 @@
 import com.google.common.annotations.VisibleForTesting;
 import com.google.common.base.Preconditions;
 import com.google.common.util.concurrent.MoreExecutors;
+import com.google.spanner.v1.BatchWriteResponse;
 import com.google.spanner.v1.BeginTransactionRequest;
 import com.google.spanner.v1.RequestOptions;
 import com.google.spanner.v1.Transaction;
@@ -505,6 +507,14 @@ public CommitResponse writeAtLeastOnceWithOptions(
         .writeAtLeastOnceWithOptions(mutations, options);
   }
 
+  @Override
+  public ServerStream<BatchWriteResponse> batchWriteAtLeastOnce(
+      Iterable<MutationGroup> mutationGroups, TransactionOption... options)
+      throws SpannerException {
+    return createMultiplexedSessionTransaction(/* singleUse = */ true)
+        .batchWriteAtLeastOnce(mutationGroups, options);
+  }
+
   @Override
   public ReadContext singleUse() {
     return createMultiplexedSessionTransaction(/* singleUse = */ true).singleUse();

google-cloud-spanner/src/main/java/com/google/cloud/spanner/SessionImpl.java

@@ -321,6 +321,7 @@ public ServerStream<BatchWriteResponse> batchWriteAtLeastOnce(
       throw SpannerExceptionFactory.newSpannerException(e);
     } finally {
       span.end();
+      onTransactionDone();
     }
   }
 

google-cloud-spanner/src/test/java/com/google/cloud/spanner/MultiplexedSessionDatabaseClientMockServerTest.java

@@ -30,6 +30,7 @@
 
 import com.google.api.core.ApiFuture;
 import com.google.api.core.ApiFutures;
+import com.google.api.gax.rpc.ServerStream;
 import com.google.cloud.NoCredentials;
 import com.google.cloud.Timestamp;
 import com.google.cloud.spanner.AsyncTransactionManager.AsyncTransactionStep;
@@ -45,6 +46,8 @@
 import com.google.common.collect.Lists;
 import com.google.common.util.concurrent.MoreExecutors;
 import com.google.protobuf.ByteString;
+import com.google.spanner.v1.BatchWriteRequest;
+import com.google.spanner.v1.BatchWriteResponse;
 import com.google.spanner.v1.BeginTransactionRequest;
 import com.google.spanner.v1.CommitRequest;
 import com.google.spanner.v1.ExecuteSqlRequest;
@@ -1635,6 +1638,44 @@ public void testReadWriteTransactionWithCommitRetryProtocolExtensionSet() {
     assertEquals(1L, client.multiplexedSessionDatabaseClient.getNumSessionsReleased().get());
   }
 
+  @Test
+  public void testBatchWriteAtLeastOnce() {
+    DatabaseClientImpl client =
+        (DatabaseClientImpl) spanner.getDatabaseClient(DatabaseId.of("p", "i", "d"));
+
+    Iterable<MutationGroup> MUTATION_GROUPS =
+        ImmutableList.of(
+            MutationGroup.of(
+                Mutation.newInsertBuilder("FOO1").set("ID").to(1L).set("NAME").to("Bar1").build(),
+                Mutation.newInsertBuilder("FOO2").set("ID").to(2L).set("NAME").to("Bar2").build()),
+            MutationGroup.of(
+                Mutation.newInsertBuilder("FOO3").set("ID").to(3L).set("NAME").to("Bar3").build(),
+                Mutation.newInsertBuilder("FOO4").set("ID").to(4L).set("NAME").to("Bar4").build()));
+
+    ServerStream<BatchWriteResponse> responseStream = client.batchWriteAtLeastOnce(MUTATION_GROUPS);
+    int idx = 0;
+    for (BatchWriteResponse response : responseStream) {
+      assertEquals(
+          response.getStatus(),
+          com.google.rpc.Status.newBuilder().setCode(com.google.rpc.Code.OK_VALUE).build());
+      assertEquals(response.getIndexesList(), ImmutableList.of(idx, idx + 1));
+      idx += 2;
+    }
+
+    assertNotNull(responseStream);
+    List<BatchWriteRequest> requests = mockSpanner.getRequestsOfType(BatchWriteRequest.class);
+    assertEquals(requests.size(), 1);
+    BatchWriteRequest request = requests.get(0);
+    assertTrue(mockSpanner.getSession(request.getSession()).getMultiplexed());
+    assertEquals(request.getMutationGroupsCount(), 2);
+    assertEquals(request.getRequestOptions().getPriority(), Priority.PRIORITY_UNSPECIFIED);
+    assertFalse(request.getExcludeTxnFromChangeStreams());
+
+    assertNotNull(client.multiplexedSessionDatabaseClient);
+    assertEquals(1L, client.multiplexedSessionDatabaseClient.getNumSessionsAcquired().get());
+    assertEquals(1L, client.multiplexedSessionDatabaseClient.getNumSessionsReleased().get());
+  }
+
   private void waitForSessionToBeReplaced(DatabaseClientImpl client) {
     assertNotNull(client.multiplexedSessionDatabaseClient);
     SessionReference sessionReference =