feat: add support for tagging

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

@@ -563,6 +563,12 @@ RequestOptions buildRequestOptions(Options options) {
     if (options.hasPriority()) {
       builder.setPriority(options.priority());
     }
+    if (options.hasTag()) {
+      builder.setRequestTag(options.tag());
+    }
+    if (getTransactionTag() != null) {
+      builder.setTransactionTag(getTransactionTag());
+    }
     return builder.build();
   }
 
@@ -707,6 +713,15 @@ public void close() {
   @Nullable
   abstract TransactionSelector getTransactionSelector();
 
+  /**
+   * Returns the transaction tag for this {@link AbstractReadContext} or <code>null</code> if this
+   * {@link AbstractReadContext} does not have a transaction tag.
+   */
+  @Nullable
+  String getTransactionTag() {
+    return null;
+  }
+
   /** This method is called when a statement returned a new transaction as part of its results. */
   @Override
   public void onTransactionMetadata(Transaction transaction, boolean shouldIncludeId) {}

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

@@ -101,6 +101,14 @@ public static ReadQueryUpdateTransactionOption priority(RpcPriority priority) {
     return new PriorityOption(priority);
   }
 
+  /**
+   * Specifying this will cause the reads, queries, updates and writes operations statistics
+   * collection to be grouped by tag.
+   */
+  public static ReadQueryUpdateTransactionOption tag(String name) {
+    return new TagOption(name);
+  }
+
   /**
    * Specifying this will cause the list operations to fetch at most this many records in a page.
    */
@@ -194,6 +202,19 @@ void appendToOptions(Options options) {
     }
   }
 
+  static final class TagOption extends InternalOption implements ReadQueryUpdateTransactionOption {
+    private final String tag;
+
+    TagOption(String tag) {
+      this.tag = tag;
+    }
+
+    @Override
+    void appendToOptions(Options options) {
+      options.tag = tag;
+    }
+  }
+
   private boolean withCommitStats;
   private Long limit;
   private Integer prefetchChunks;
@@ -202,6 +223,7 @@ void appendToOptions(Options options) {
   private String pageToken;
   private String filter;
   private RpcPriority priority;
+  private String tag;
 
   // Construction is via factory methods below.
   private Options() {}
@@ -266,6 +288,14 @@ Priority priority() {
     return priority == null ? null : priority.proto;
   }
 
+  boolean hasTag() {
+    return tag != null;
+  }
+
+  String tag() {
+    return tag;
+  }
+
   @Override
   public String toString() {
     StringBuilder b = new StringBuilder();
@@ -290,6 +320,9 @@ public String toString() {
     if (priority != null) {
       b.append("priority: ").append(priority).append(' ');
     }
+    if (tag != null) {
+      b.append("tag: ").append(tag).append(' ');
+    }
     return b.toString();
   }
 
@@ -320,7 +353,8 @@ public boolean equals(Object o) {
             || hasPageSize() && that.hasPageSize() && Objects.equals(pageSize(), that.pageSize()))
         && Objects.equals(pageToken(), that.pageToken())
         && Objects.equals(filter(), that.filter())
-        && Objects.equals(priority(), that.priority());
+        && Objects.equals(priority(), that.priority())
+        && Objects.equals(tag(), that.tag());
   }
 
   @Override
@@ -350,6 +384,9 @@ public int hashCode() {
     if (priority != null) {
       result = 31 * result + priority.hashCode();
     }
+    if (tag != null) {
+      result = 31 * result + tag.hashCode();
+    }
     return result;
   }
 

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

@@ -181,11 +181,16 @@ ExecuteSqlRequest newTransactionRequestFrom(final Statement statement, final Opt
 
     builder.setResumeToken(ByteString.EMPTY);
 
-    if (options.hasPriority()) {
-      builder.setRequestOptions(
-          RequestOptions.newBuilder().setPriority(options.priority()).build());
+    if (options.hasPriority() || options.hasTag()) {
+      RequestOptions.Builder requestOptionsBuilder = RequestOptions.newBuilder();
+      if (options.hasPriority()) {
+        requestOptionsBuilder.setPriority(options.priority());
+      }
+      if (options.hasTag()) {
+        requestOptionsBuilder.setRequestTag(options.tag());
+      }
+      builder.setRequestOptions(requestOptionsBuilder.build());
     }
-
     return builder.build();
   }
 

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

@@ -173,9 +173,15 @@ public CommitResponse writeAtLeastOnceWithOptions(
             .setSingleUseTransaction(
                 TransactionOptions.newBuilder()
                     .setReadWrite(TransactionOptions.ReadWrite.getDefaultInstance()));
-    if (commitRequestOptions.hasPriority()) {
-      requestBuilder.setRequestOptions(
-          RequestOptions.newBuilder().setPriority(commitRequestOptions.priority()).build());
+    if (commitRequestOptions.hasPriority() || commitRequestOptions.hasTag()) {
+      RequestOptions.Builder requestOptionsBuilder = RequestOptions.newBuilder();
+      if (commitRequestOptions.hasPriority()) {
+        requestOptionsBuilder.setPriority(commitRequestOptions.priority());
+      }
+      if (commitRequestOptions.hasTag()) {
+        requestOptionsBuilder.setTransactionTag(commitRequestOptions.tag());
+      }
+      requestBuilder.setRequestOptions(requestOptionsBuilder.build());
     }
     Span span = tracer.spanBuilder(SpannerImpl.COMMIT).startSpan();
     try (Scope s = tracer.withSpan(span)) {

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

@@ -299,9 +299,15 @@ ApiFuture<CommitResponse> commitAsync() {
           CommitRequest.newBuilder()
               .setSession(session.getName())
               .setReturnCommitStats(options.withCommitStats());
-      if (options.hasPriority()) {
-        builder.setRequestOptions(
-            RequestOptions.newBuilder().setPriority(options.priority()).build());
+      if (options.hasPriority() || getTransactionTag() != null) {
+        RequestOptions.Builder requestOptionsBuilder = RequestOptions.newBuilder();
+        if (options.hasPriority()) {
+          requestOptionsBuilder.setPriority(options.priority());
+        }
+        if (getTransactionTag() != null) {
+          requestOptionsBuilder.setTransactionTag(getTransactionTag());
+        }
+        builder.setRequestOptions(requestOptionsBuilder.build());
       }
       synchronized (lock) {
         if (transactionIdFuture == null && transactionId == null && runningAsyncOperations == 0) {
@@ -349,9 +355,15 @@ public void run() {
             requestBuilder.setTransactionId(
                 transactionId == null ? transactionIdFuture.get() : transactionId);
           }
-          if (options.hasPriority()) {
-            requestBuilder.setRequestOptions(
-                RequestOptions.newBuilder().setPriority(options.priority()).build());
+          if (options.hasPriority() || getTransactionTag() != null) {
+            RequestOptions.Builder requestOptionsBuilder = RequestOptions.newBuilder();
+            if (options.hasPriority()) {
+              requestOptionsBuilder.setPriority(options.priority());
+            }
+            if (getTransactionTag() != null) {
+              requestOptionsBuilder.setTransactionTag(getTransactionTag());
+            }
+            requestBuilder.setRequestOptions(requestOptionsBuilder.build());
           }
           final CommitRequest commitRequest = requestBuilder.build();
           span.addAnnotation("Starting Commit");
@@ -531,6 +543,12 @@ public void onTransactionMetadata(Transaction transaction, boolean shouldInclude
       }
     }
 
+    @Nullable
+    String getTransactionTag() {
+      if (this.options.hasTag()) return this.options.tag();
+      return null;
+    }
+
     @Override
     public SpannerException onError(SpannerException e, boolean withBeginTransaction) {
       // If the statement that caused an error was the statement that included a BeginTransaction

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

@@ -64,6 +64,14 @@ TestReadContext build() {
     }
   }
 
+  class TestReadContextWithTagBuilder
+      extends AbstractReadContext.Builder<TestReadContextWithTagBuilder, TestReadContextWithTag> {
+    @Override
+    TestReadContextWithTag build() {
+      return new TestReadContextWithTag(this);
+    }
+  }
+
   private final class TestReadContext extends AbstractReadContext {
     TestReadContext(TestReadContextBuilder builder) {
       super(builder);
@@ -75,6 +83,21 @@ TransactionSelector getTransactionSelector() {
     }
   }
 
+  private final class TestReadContextWithTag extends AbstractReadContext {
+    TestReadContextWithTag(TestReadContextWithTagBuilder builder) {
+      super(builder);
+    }
+
+    @Override
+    TransactionSelector getTransactionSelector() {
+      return TransactionSelector.getDefaultInstance();
+    }
+
+    String getTransactionTag() {
+      return "app=spanner,env=test";
+    }
+  }
+
   private TestReadContext context;
 
   @Before
@@ -162,4 +185,46 @@ public void testGetExecuteBatchDmlRequestBuilderWithPriority() {
             Options.fromQueryOptions(Options.priority(RpcPriority.LOW)));
     assertEquals(Priority.PRIORITY_LOW, request.getRequestOptions().getPriority());
   }
+
+  public void executeSqlRequestBuilderWithRequestOptions() {
+    ExecuteSqlRequest request =
+        context
+            .getExecuteSqlRequestBuilder(
+                Statement.newBuilder("SELECT FOO FROM BAR").build(),
+                QueryMode.NORMAL,
+                Options.fromUpdateOptions(Options.tag("app=spanner,env=test,action=query")),
+                false)
+            .build();
+    assertThat(request.getSql()).isEqualTo("SELECT FOO FROM BAR");
+    assertThat(request.getRequestOptions().getRequestTag())
+        .isEqualTo("app=spanner,env=test,action=query");
+    assertThat(request.getRequestOptions().getTransactionTag()).isEmpty();
+  }
+
+  @Test
+  public void executeSqlRequestBuilderWithRequestOptionsWithTxnTag() {
+    SessionImpl session = mock(SessionImpl.class);
+    when(session.getName()).thenReturn("session-1");
+    TestReadContextWithTagBuilder builder = new TestReadContextWithTagBuilder();
+    TestReadContextWithTag contextWithTag =
+        builder
+            .setSession(session)
+            .setRpc(mock(SpannerRpc.class))
+            .setDefaultQueryOptions(defaultQueryOptions)
+            .setExecutorProvider(mock(ExecutorProvider.class))
+            .build();
+
+    ExecuteSqlRequest request =
+        contextWithTag
+            .getExecuteSqlRequestBuilder(
+                Statement.newBuilder("SELECT FOO FROM BAR").build(),
+                QueryMode.NORMAL,
+                Options.fromUpdateOptions(Options.tag("app=spanner,env=test,action=query")),
+                false)
+            .build();
+    assertThat(request.getSql()).isEqualTo("SELECT FOO FROM BAR");
+    assertThat(request.getRequestOptions().getRequestTag())
+        .isEqualTo("app=spanner,env=test,action=query");
+    assertThat(request.getRequestOptions().getTransactionTag()).isEqualTo("app=spanner,env=test");
+  }
 }