netty: extract default permit keepalive time to GrpcUtil constant (grpc#12754)

A simple change that makes the permit keepalive time value a constant.

Author: therepanic

core/src/main/java/io/grpc/internal/GrpcUtil.java

@@ -241,6 +241,12 @@ public byte[] parseAsciiString(byte[] serialized) {
    */
   public static final long DEFAULT_SERVER_KEEPALIVE_TIMEOUT_NANOS = TimeUnit.SECONDS.toNanos(20L);
 
+  /**
+   * The default minimum time between client keepalive pings permitted by server.
+   */
+  public static final long DEFAULT_SERVER_PERMIT_KEEPALIVE_TIME_NANOS
+          = TimeUnit.MINUTES.toNanos(5L);
+
   /**
    * The magic keepalive time value that disables keepalive.
    */

netty/src/main/java/io/grpc/netty/NettyServerBuilder.java

@@ -22,6 +22,7 @@
 import static io.grpc.internal.GrpcUtil.DEFAULT_MAX_MESSAGE_SIZE;
 import static io.grpc.internal.GrpcUtil.DEFAULT_SERVER_KEEPALIVE_TIMEOUT_NANOS;
 import static io.grpc.internal.GrpcUtil.DEFAULT_SERVER_KEEPALIVE_TIME_NANOS;
+import static io.grpc.internal.GrpcUtil.DEFAULT_SERVER_PERMIT_KEEPALIVE_TIME_NANOS;
 import static io.grpc.internal.GrpcUtil.SERVER_KEEPALIVE_TIME_NANOS_DISABLED;
 
 import com.google.common.annotations.VisibleForTesting;
@@ -113,7 +114,7 @@ public final class NettyServerBuilder extends ForwardingServerBuilder<NettyServe
   private long maxConnectionAgeInNanos = MAX_CONNECTION_AGE_NANOS_DISABLED;
   private long maxConnectionAgeGraceInNanos = MAX_CONNECTION_AGE_GRACE_NANOS_INFINITE;
   private boolean permitKeepAliveWithoutCalls;
-  private long permitKeepAliveTimeInNanos = TimeUnit.MINUTES.toNanos(5);
+  private long permitKeepAliveTimeInNanos = DEFAULT_SERVER_PERMIT_KEEPALIVE_TIME_NANOS;
   private int maxRstCount;
   private long maxRstPeriodNanos;
   private Attributes eagAttributes = Attributes.EMPTY;

okhttp/src/main/java/io/grpc/okhttp/OkHttpServerBuilder.java

@@ -18,6 +18,7 @@
 
 import static com.google.common.base.Preconditions.checkArgument;
 import static io.grpc.internal.CertificateUtils.createTrustManager;
+import static io.grpc.internal.GrpcUtil.DEFAULT_SERVER_PERMIT_KEEPALIVE_TIME_NANOS;
 
 import com.google.common.base.Preconditions;
 import com.google.errorprone.annotations.CanIgnoreReturnValue;
@@ -137,7 +138,7 @@ public InternalServer buildClientTransportServers(
   int maxInboundMessageSize = GrpcUtil.DEFAULT_MAX_MESSAGE_SIZE;
   long maxConnectionIdleInNanos = MAX_CONNECTION_IDLE_NANOS_DISABLED;
   boolean permitKeepAliveWithoutCalls;
-  long permitKeepAliveTimeInNanos = TimeUnit.MINUTES.toNanos(5);
+  long permitKeepAliveTimeInNanos = DEFAULT_SERVER_PERMIT_KEEPALIVE_TIME_NANOS;
   long maxConnectionAgeInNanos = MAX_CONNECTION_AGE_NANOS_DISABLED;
   long maxConnectionAgeGraceInNanos = MAX_CONNECTION_AGE_GRACE_NANOS_INFINITE;
   int maxConcurrentCallsPerConnection = MAX_CONCURRENT_STREAMS;