feat: enable client to server compression (#2117)

Enable compression of network traffic from client to server. See the below screenshots from Wireshark for tests that show that the compression works both ways. Note: The rate of compression will depend on the type of data that is being sent. The below example for client->server communication is for sending 1,000 very similar mutations to Spanner. That compresses very well with gzip. More random data will compress less. ### Server -> Client - No Compression ![server-_client identity](https://user-images.githubusercontent.com/1196707/196627944-4d6f34fa-78a9-4023-a848-51a0ffe5228e.png) ### Server -> Client - Gzip Compression ![server-_client gzip](https://user-images.githubusercontent.com/1196707/196627948-d2d574ed-3f69-4b3c-8613-c162e21e207d.png) ### Client -> Server - No Compression ![client-_server identity](https://user-images.githubusercontent.com/1196707/196627950-b01ecb88-f6e8-4fd9-b7f8-257ad4211ac9.png) ### Client -> Server - Gzip Compression ![client-_server gzip](https://user-images.githubusercontent.com/1196707/196627952-ecf8b4bd-cd44-4941-af55-6aecaf03f69e.png)

Author: olavloite

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

@@ -1060,7 +1060,8 @@ public Builder setCallCredentialsProvider(CallCredentialsProvider callCredential
 
  /**
  * Sets the compression to use for all gRPC calls. The compressor must be a valid name known in
- * the {@link CompressorRegistry}.
+ * the {@link CompressorRegistry}. This will enable compression both from the client to the
+ * server and from the server to the client.
  *
  * <p>Supported values are:
  *

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

@@ -389,6 +389,7 @@ public GapicSpannerRpc(final SpannerOptions options) {
  MoreObjects.firstNonNull(
  options.getInterceptorProvider(),
  SpannerInterceptorProvider.createDefault()))
+ // This sets the response compressor (Server -> Client).
  .withEncoding(compressorName))
  .setHeaderProvider(headerProviderWithUserAgent)
  // Attempts direct access to spanner service over gRPC to improve throughput,
@@ -1901,6 +1902,10 @@ <ReqT, RespT> GrpcCallContext newCallContext(
  if (options != null) {
  context = context.withChannelAffinity(Option.CHANNEL_HINT.getLong(options).intValue());
  }
+ if (compressorName != null) {
+ // This sets the compressor for Client -> Server.
+ context = context.withCallOptions(context.getCallOptions().withCompression(compressorName));
+ }
  context = context.withExtraHeaders(metadataProvider.newExtraHeaders(resource, projectName));
  if (callCredentialsProvider != null) {
  CallCredentials callCredentials = callCredentialsProvider.getCallCredentials();

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

@@ -130,6 +130,12 @@ public <ReqT, RespT> ServerCall.Listener<ReqT> interceptCall(
  ServerCall<ReqT, RespT> call,
  Metadata headers,
  ServerCallHandler<ReqT, RespT> next) {
+ // Verify that the compressor name header is set.
+ assertEquals(
+ "gzip",
+ headers.get(
+ Metadata.Key.of(
+ "x-response-encoding", Metadata.ASCII_STRING_MARSHALLER)));
  Attributes attributes = call.getAttributes();
  @SuppressWarnings({"unchecked", "deprecation"})
  Attributes.Key<InetSocketAddress> key =
@@ -179,6 +185,7 @@ private SpannerOptions createSpannerOptions() {
  return input;
  })
  .setNumChannels(numChannels)
+ .setCompressorName("gzip")
  .setSessionPoolOption(
  SessionPoolOptions.newBuilder()
  .setMinSessions(numChannels * 2)

google-cloud-spanner/src/test/java/com/google/cloud/spanner/spi/v1/GapicSpannerRpcTest.java

@@ -19,6 +19,7 @@
 import static com.google.common.truth.Truth.assertThat;
 import static org.hamcrest.MatcherAssert.assertThat;
 import static org.junit.Assert.assertEquals;
+import static org.junit.Assert.assertNull;
 import static org.junit.Assert.assertThrows;
 import static org.junit.Assume.assumeTrue;
 
@@ -259,6 +260,58 @@ public void testNoCallCredentials() {
  rpc.shutdown();
  }
 
+ @Test
+ public void testClientCompressorGzip() {
+ SpannerOptions options =
+ SpannerOptions.newBuilder().setProjectId("some-project").setCompressorName("gzip").build();
+ GapicSpannerRpc rpc = new GapicSpannerRpc(options, false);
+ assertEquals(
+ "gzip",
+ rpc.newCallContext(
+ optionsMap,
+ "/some/resource",
+ GetSessionRequest.getDefaultInstance(),
+ SpannerGrpc.getGetSessionMethod())
+ .getCallOptions()
+ .getCompressor());
+ rpc.shutdown();
+ }
+
+ @Test
+ public void testClientCompressorIdentity() {
+ SpannerOptions options =
+ SpannerOptions.newBuilder()
+ .setProjectId("some-project")
+ .setCompressorName("identity")
+ .build();
+ GapicSpannerRpc rpc = new GapicSpannerRpc(options, false);
+ assertEquals(
+ "identity",
+ rpc.newCallContext(
+ optionsMap,
+ "/some/resource",
+ GetSessionRequest.getDefaultInstance(),
+ SpannerGrpc.getGetSessionMethod())
+ .getCallOptions()
+ .getCompressor());
+ rpc.shutdown();
+ }
+
+ @Test
+ public void testClientCompressorDefault() {
+ SpannerOptions options = SpannerOptions.newBuilder().setProjectId("some-project").build();
+ GapicSpannerRpc rpc = new GapicSpannerRpc(options, false);
+ assertNull(
+ rpc.newCallContext(
+ optionsMap,
+ "/some/resource",
+ GetSessionRequest.getDefaultInstance(),
+ SpannerGrpc.getGetSessionMethod())
+ .getCallOptions()
+ .getCompressor());
+ rpc.shutdown();
+ }
+
  private static final class TimeoutHolder {
 
  private Duration timeout;