feat: support setting compression option (#192)

* feat: support setting compression option

* fix: use correct encoding header

* fix: add project id

* docs: fix typo + missing end tag

* chore: resolve merge conflicts

* tests: fix test failure on emulator

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

@@ -49,6 +49,8 @@
 import com.google.spanner.admin.database.v1.RestoreDatabaseRequest;
 import com.google.spanner.v1.ExecuteSqlRequest.QueryOptions;
 import io.grpc.CallCredentials;
+import io.grpc.CompressorRegistry;
+import io.grpc.ExperimentalApi;
 import io.grpc.ManagedChannelBuilder;
 import java.io.IOException;
 import java.net.MalformedURLException;
@@ -58,6 +60,7 @@
 import java.util.Map.Entry;
 import java.util.Set;
 import javax.annotation.Nonnull;
+import javax.annotation.Nullable;
 import org.threeten.bp.Duration;
 
 /** Options for the Cloud Spanner service. */
@@ -104,6 +107,7 @@ public class SpannerOptions extends ServiceOptions<Spanner, SpannerOptions> {
   private final Map<DatabaseId, QueryOptions> mergedQueryOptions;
 
   private final CallCredentialsProvider callCredentialsProvider;
+  private final String compressorName;
 
   /**
    * Interface that can be used to provide {@link CallCredentials} instead of {@link Credentials} to
@@ -174,6 +178,7 @@ private SpannerOptions(Builder builder) {
       this.mergedQueryOptions = ImmutableMap.copyOf(merged);
     }
     callCredentialsProvider = builder.callCredentialsProvider;
+    compressorName = builder.compressorName;
   }
 
   /**
@@ -238,6 +243,7 @@ public static class Builder
     private boolean autoThrottleAdministrativeRequests = false;
     private Map<DatabaseId, QueryOptions> defaultQueryOptions = new HashMap<>();
     private CallCredentialsProvider callCredentialsProvider;
+    private String compressorName;
     private String emulatorHost = System.getenv("SPANNER_EMULATOR_HOST");
 
     private Builder() {
@@ -309,6 +315,7 @@ private Builder() {
       this.autoThrottleAdministrativeRequests = options.autoThrottleAdministrativeRequests;
       this.defaultQueryOptions = options.defaultQueryOptions;
       this.callCredentialsProvider = options.callCredentialsProvider;
+      this.compressorName = options.compressorName;
       this.channelProvider = options.channelProvider;
       this.channelConfigurator = options.channelConfigurator;
       this.interceptorProvider = options.interceptorProvider;
@@ -558,6 +565,28 @@ public Builder setCallCredentialsProvider(CallCredentialsProvider callCredential
       return this;
     }
 
+    /**
+     * Sets the compression to use for all gRPC calls. The compressor must be a valid name known in
+     * the {@link CompressorRegistry}.
+     *
+     * <p>Supported values are:
+     *
+     * <ul>
+     *   <li>gzip: Enable gzip compression
+     *   <li>identity: Disable compression
+     *   <li><code>null</code>: Use default compression
+     * </ul>
+     */
+    @ExperimentalApi("https://github.com/grpc/grpc-java/issues/1704")
+    public Builder setCompressorName(@Nullable String compressorName) {
+      Preconditions.checkArgument(
+          compressorName == null
+              || CompressorRegistry.getDefaultInstance().lookupCompressor(compressorName) != null,
+          String.format("%s is not a known compressor", compressorName));
+      this.compressorName = compressorName;
+      return this;
+    }
+
     /**
      * Specifying this will allow the client to prefetch up to {@code prefetchChunks} {@code
      * PartialResultSet} chunks for each read and query. The data size of each chunk depends on the
@@ -690,6 +719,10 @@ public CallCredentialsProvider getCallCredentialsProvider() {
     return callCredentialsProvider;
   }
 
+  public String getCompressorName() {
+    return compressorName;
+  }
+
   /** Returns the default query options to use for the specific database. */
   public QueryOptions getDefaultQueryOptions(DatabaseId databaseId) {
     // Use the specific query options for the database if any have been specified. These have

google-cloud-spanner/src/main/java/com/google/cloud/spanner/spi/v1/EncodingInterceptor.java

@@ -0,0 +1,50 @@
+/*
+ * Copyright 2020 Google LLC
+ *
+ * Licensed under the Apache License, Version 2.0 (the "License");
+ * you may not use this file except in compliance with the License.
+ * You may obtain a copy of the License at
+ *
+ *       http://www.apache.org/licenses/LICENSE-2.0
+ *
+ * Unless required by applicable law or agreed to in writing, software
+ * distributed under the License 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.
+ */
+package com.google.cloud.spanner.spi.v1;
+
+import io.grpc.CallOptions;
+import io.grpc.Channel;
+import io.grpc.ClientCall;
+import io.grpc.ClientInterceptor;
+import io.grpc.ForwardingClientCall;
+import io.grpc.Metadata;
+import io.grpc.Metadata.Key;
+import io.grpc.MethodDescriptor;
+
+class EncodingInterceptor implements ClientInterceptor {
+  private static final String RESPONSE_ENCODING_KEY_NAME = "x-response-encoding";
+  private static final Key<String> RESPONSE_ENCODING_KEY =
+      Metadata.Key.of(RESPONSE_ENCODING_KEY_NAME, Metadata.ASCII_STRING_MARSHALLER);
+
+  private final String encoding;
+
+  EncodingInterceptor(String encoding) {
+    this.encoding = encoding;
+  }
+
+  @Override
+  public <ReqT, RespT> ClientCall<ReqT, RespT> interceptCall(
+      MethodDescriptor<ReqT, RespT> method, CallOptions callOptions, Channel next) {
+    return new ForwardingClientCall.SimpleForwardingClientCall<ReqT, RespT>(
+        next.newCall(method, callOptions)) {
+      @Override
+      public void start(Listener<RespT> responseListener, Metadata headers) {
+        headers.put(RESPONSE_ENCODING_KEY, encoding);
+        super.start(responseListener, headers);
+      }
+    };
+  }
+}

google-cloud-spanner/src/main/java/com/google/cloud/spanner/spi/v1/GapicSpannerRpc.java

@@ -231,6 +231,7 @@ private void awaitTermination() throws InterruptedException {
   private final String projectName;
   private final SpannerMetadataProvider metadataProvider;
   private final CallCredentialsProvider callCredentialsProvider;
+  private final String compressorName;
   private final Duration waitTimeout =
       systemProperty(PROPERTY_TIMEOUT_SECONDS, DEFAULT_TIMEOUT_SECONDS);
   private final Duration idleTimeout =
@@ -284,6 +285,7 @@ public GapicSpannerRpc(final SpannerOptions options) {
             mergedHeaderProvider.getHeaders(),
             internalHeaderProviderBuilder.getResourceHeaderKey());
     this.callCredentialsProvider = options.getCallCredentialsProvider();
+    this.compressorName = options.getCompressorName();
 
     // Create a managed executor provider.
     this.executorProvider =
@@ -312,9 +314,11 @@ public GapicSpannerRpc(final SpannerOptions options) {
                 // Then check if SpannerOptions provides an InterceptorProvider. Create a default
                 // SpannerInterceptorProvider if none is provided
                 .setInterceptorProvider(
-                    MoreObjects.firstNonNull(
-                        options.getInterceptorProvider(),
-                        SpannerInterceptorProvider.createDefault()))
+                    SpannerInterceptorProvider.create(
+                            MoreObjects.firstNonNull(
+                                options.getInterceptorProvider(),
+                                SpannerInterceptorProvider.createDefault()))
+                        .withEncoding(compressorName))
                 .setHeaderProvider(mergedHeaderProvider)
                 .build());
 

google-cloud-spanner/src/main/java/com/google/cloud/spanner/spi/v1/SpannerInterceptorProvider.java

@@ -45,6 +45,10 @@ public static SpannerInterceptorProvider createDefault() {
     return new SpannerInterceptorProvider(defaultInterceptors);
   }
 
+  static SpannerInterceptorProvider create(GrpcInterceptorProvider provider) {
+    return new SpannerInterceptorProvider(ImmutableList.copyOf(provider.getInterceptors()));
+  }
+
   public SpannerInterceptorProvider with(ClientInterceptor clientInterceptor) {
     List<ClientInterceptor> interceptors =
         ImmutableList.<ClientInterceptor>builder()
@@ -54,6 +58,13 @@ public SpannerInterceptorProvider with(ClientInterceptor clientInterceptor) {
     return new SpannerInterceptorProvider(interceptors);
   }
 
+  SpannerInterceptorProvider withEncoding(String encoding) {
+    if (encoding != null) {
+      return with(new EncodingInterceptor(encoding));
+    }
+    return this;
+  }
+
   @Override
   public List<ClientInterceptor> getInterceptors() {
     return clientInterceptors;

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

@@ -505,4 +505,35 @@ public String getOptimizerVersion() {
     assertThat(options.getDefaultQueryOptions(DatabaseId.of("p", "i", "o")))
         .isEqualTo(QueryOptions.newBuilder().setOptimizerVersion("2").build());
   }
+
+  @Test
+  public void testCompressorName() {
+    assertThat(
+            SpannerOptions.newBuilder()
+                .setProjectId("p")
+                .setCompressorName("gzip")
+                .build()
+                .getCompressorName())
+        .isEqualTo("gzip");
+    assertThat(
+            SpannerOptions.newBuilder()
+                .setProjectId("p")
+                .setCompressorName("identity")
+                .build()
+                .getCompressorName())
+        .isEqualTo("identity");
+    assertThat(
+            SpannerOptions.newBuilder()
+                .setProjectId("p")
+                .setCompressorName(null)
+                .build()
+                .getCompressorName())
+        .isNull();
+    try {
+      SpannerOptions.newBuilder().setCompressorName("foo");
+      fail("missing expected exception");
+    } catch (IllegalArgumentException e) {
+      // ignore, this is the expected exception.
+    }
+  }
 }

google-cloud-spanner/src/test/java/com/google/cloud/spanner/it/ITSpannerOptionsTest.java

@@ -0,0 +1,68 @@
+/*
+ * Copyright 2019 Google LLC
+ *
+ * Licensed under the Apache License, Version 2.0 (the "License");
+ * you may not use this file except in compliance with the License.
+ * You may obtain a copy of the License at
+ *
+ *       http://www.apache.org/licenses/LICENSE-2.0
+ *
+ * Unless required by applicable law or agreed to in writing, software
+ * distributed under the License 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.
+ */
+
+package com.google.cloud.spanner.it;
+
+import static com.google.common.truth.Truth.assertThat;
+
+import com.google.cloud.spanner.Database;
+import com.google.cloud.spanner.DatabaseClient;
+import com.google.cloud.spanner.IntegrationTestEnv;
+import com.google.cloud.spanner.ParallelIntegrationTest;
+import com.google.cloud.spanner.ResultSet;
+import com.google.cloud.spanner.Spanner;
+import com.google.cloud.spanner.SpannerOptions;
+import com.google.cloud.spanner.Statement;
+import org.junit.AfterClass;
+import org.junit.BeforeClass;
+import org.junit.ClassRule;
+import org.junit.Test;
+import org.junit.experimental.categories.Category;
+import org.junit.runner.RunWith;
+import org.junit.runners.JUnit4;
+
+@Category(ParallelIntegrationTest.class)
+@RunWith(JUnit4.class)
+public class ITSpannerOptionsTest {
+  @ClassRule public static IntegrationTestEnv env = new IntegrationTestEnv();
+  private static Database db;
+
+  @BeforeClass
+  public static void setUp() throws Exception {
+    db = env.getTestHelper().createTestDatabase();
+  }
+
+  @AfterClass
+  public static void tearDown() throws Exception {
+    db.drop();
+  }
+
+  @Test
+  public void testCompression() {
+    for (String compressorName : new String[] {"gzip", "identity", null}) {
+      SpannerOptions options =
+          env.getTestHelper().getOptions().toBuilder().setCompressorName(compressorName).build();
+      try (Spanner spanner = options.getService()) {
+        DatabaseClient client = spanner.getDatabaseClient(db.getId());
+        try (ResultSet rs = client.singleUse().executeQuery(Statement.of("SELECT 1 AS COL1"))) {
+          assertThat(rs.next()).isTrue();
+          assertThat(rs.getLong(0)).isEqualTo(1L);
+          assertThat(rs.next()).isFalse();
+        }
+      }
+    }
+  }
+}