Add a log filter for spurious warnings about unsupported channel options

service/src/main/java/org/whispersystems/textsecuregcm/util/logging/UnknownKeepaliveOptionFilter.java

@@ -0,0 +1,26 @@
+package org.whispersystems.textsecuregcm.util.logging;
+
+import ch.qos.logback.classic.spi.ILoggingEvent;
+import ch.qos.logback.core.filter.Filter;
+import ch.qos.logback.core.spi.FilterReply;
+
+/**
+ * Filters spurious warnings about setting a very specific channel option on local channels.
+ * <p/>
+ * gRPC unconditionally tries to set the {@code SO_KEEPALIVE} option on all of its channels, but local channels, which
+ * are used by the Noise-over-WebSocket tunnel, do not support {@code SO_KEEPALIVE} and log a warning on each new
+ * channel. We don't want to filter <em>all</em> warnings from the relevant logger, and so this custom filter denies
+ * attempts to log the specific spurious message.
+ */
+public class UnknownKeepaliveOptionFilter extends Filter<ILoggingEvent> {
+
+  private static final String MESSAGE_PREFIX = "Unknown channel option 'SO_KEEPALIVE'";
+
+  @Override
+  public FilterReply decide(final ILoggingEvent event) {
+    final boolean loggerNameMatches = "io.netty.bootstrap.Bootstrap".equals(event.getLoggerName()) ||
+        "io.netty.bootstrap.ServerBootstrap".equals(event.getLoggerName());
+
+    return loggerNameMatches && event.getMessage().startsWith(MESSAGE_PREFIX) ? FilterReply.DENY : FilterReply.NEUTRAL;
+  }
+}

service/src/main/java/org/whispersystems/textsecuregcm/util/logging/UnknownKeepaliveOptionFilterFactory.java

@@ -0,0 +1,15 @@
+package org.whispersystems.textsecuregcm.util.logging;
+
+import ch.qos.logback.classic.spi.ILoggingEvent;
+import ch.qos.logback.core.filter.Filter;
+import com.fasterxml.jackson.annotation.JsonTypeName;
+import io.dropwizard.logging.common.filter.FilterFactory;
+
+@JsonTypeName("unknownKeepaliveOption")
+public class UnknownKeepaliveOptionFilterFactory implements FilterFactory<ILoggingEvent> {
+
+  @Override
+  public Filter<ILoggingEvent> build() {
+    return new UnknownKeepaliveOptionFilter();
+  }
+}