feat: add keepalive changes in java client library (#409)

* feat: Add keepalive logic in bigtable data client * fix: code formatting * fix: mvn formatting * fix: setting in emulator * feat: add keep alive in enhanced stub as well

Author: sushanb

google-cloud-bigtable-emulator/src/main/java/com/google/cloud/bigtable/emulator/v2/Emulator.java

@@ -179,7 +179,13 @@ public synchronized ManagedChannel getDataChannel() {
  }
 
  if (dataChannel == null) {
- dataChannel = newChannelBuilder(port).maxInboundMessageSize(256 * 1024 * 1024).build();
+ dataChannel =
+ newChannelBuilder(port)
+ .maxInboundMessageSize(256 * 1024 * 1024)
+ .keepAliveTimeout(10, TimeUnit.SECONDS)
+ .keepAliveTime(10, TimeUnit.SECONDS)
+ .keepAliveWithoutCalls(true)
+ .build();
  }
  return dataChannel;
  }

google-cloud-bigtable/src/main/java/com/google/cloud/bigtable/data/v2/BigtableDataSettings.java

@@ -29,6 +29,7 @@
 import java.util.List;
 import java.util.logging.Logger;
 import javax.annotation.Nonnull;
+import org.threeten.bp.Duration;
 
 /**
  * Settings class to configure an instance of {@link BigtableDataClient}.
@@ -122,6 +123,10 @@ public ManagedChannelBuilder apply(ManagedChannelBuilder input) {
  return input.usePlaintext();
  }
  })
+ .setKeepAliveTime(Duration.ofSeconds(10)) // sends ping in this interval
+ .setKeepAliveTimeout(
+ Duration.ofSeconds(10)) // wait this long before considering the connection dead
+ .setKeepAliveWithoutCalls(true) // sends ping without active streams
  .build());
 
  LOGGER.info("Connecting to the Bigtable emulator at " + hostname + ":" + port);

google-cloud-bigtable/src/main/java/com/google/cloud/bigtable/data/v2/stub/EnhancedBigtableStubSettings.java

@@ -241,6 +241,10 @@ public static InstantiatingGrpcChannelProvider.Builder defaultGrpcTransportProvi
  return BigtableStubSettings.defaultGrpcTransportProviderBuilder()
  .setPoolSize(getDefaultChannelPoolSize())
  .setMaxInboundMessageSize(MAX_MESSAGE_SIZE)
+ .setKeepAliveTime(Duration.ofSeconds(10)) // sends ping in this interval
+ .setKeepAliveTimeout(
+ Duration.ofSeconds(10)) // wait this long before considering the connection dead
+ .setKeepAliveWithoutCalls(true) // sends ping without active streams
  // TODO(weiranf): Set this to true by default once DirectPath goes to public beta
  .setAttemptDirectPath(isDirectPathEnabled());
  }