xds: Reuse filter interceptors across RPCs

This moves the interceptor creation from the ConfigSelector to the
resource update handling.

The code structure changes will make adding support for filter
lifecycles (for RLQS) a bit easier. The filter lifecycles will allow
filters to share state across interceptors, and constructing all the
interceptors on a single thread will mean filters wouldn't need to be
thread-safe (but their interceptors would be thread-safe).

Author: ejona86

xds/src/main/java/io/grpc/xds/FaultFilter.java

@@ -37,7 +37,6 @@
 import io.grpc.Deadline;
 import io.grpc.ForwardingClientCall;
 import io.grpc.ForwardingClientCallListener.SimpleForwardingClientCallListener;
-import io.grpc.LoadBalancer.PickSubchannelArgs;
 import io.grpc.Metadata;
 import io.grpc.MethodDescriptor;
 import io.grpc.Status;
@@ -183,7 +182,7 @@ public ConfigOrError<FaultConfig> parseFilterConfigOverride(Message rawProtoMess
   @Nullable
   @Override
   public ClientInterceptor buildClientInterceptor(
-      FilterConfig config, @Nullable FilterConfig overrideConfig, PickSubchannelArgs args,
+      FilterConfig config, @Nullable FilterConfig overrideConfig,
       final ScheduledExecutorService scheduler) {
     checkNotNull(config, "config");
     if (overrideConfig != null) {

xds/src/main/java/io/grpc/xds/Filter.java

@@ -19,7 +19,6 @@
 import com.google.common.base.MoreObjects;
 import com.google.protobuf.Message;
 import io.grpc.ClientInterceptor;
-import io.grpc.LoadBalancer.PickSubchannelArgs;
 import io.grpc.ServerInterceptor;
 import java.util.Objects;
 import java.util.concurrent.ScheduledExecutorService;
@@ -59,7 +58,7 @@ interface FilterConfig {
   interface ClientInterceptorBuilder {
     @Nullable
     ClientInterceptor buildClientInterceptor(
-        FilterConfig config, @Nullable FilterConfig overrideConfig, PickSubchannelArgs args,
+        FilterConfig config, @Nullable FilterConfig overrideConfig,
         ScheduledExecutorService scheduler);
   }
 

xds/src/main/java/io/grpc/xds/GcpAuthenticationFilter.java

@@ -31,7 +31,6 @@
 import io.grpc.ClientCall;
 import io.grpc.ClientInterceptor;
 import io.grpc.CompositeCallCredentials;
-import io.grpc.LoadBalancer.PickSubchannelArgs;
 import io.grpc.Metadata;
 import io.grpc.MethodDescriptor;
 import io.grpc.Status;
@@ -97,8 +96,7 @@ public ConfigOrError<? extends FilterConfig> parseFilterConfigOverride(Message r
   @Nullable
   @Override
   public ClientInterceptor buildClientInterceptor(FilterConfig config,
-      @Nullable FilterConfig overrideConfig, PickSubchannelArgs args,
-      ScheduledExecutorService scheduler) {
+      @Nullable FilterConfig overrideConfig, ScheduledExecutorService scheduler) {
 
     ComputeEngineCredentials credentials = ComputeEngineCredentials.create();
     LruCache<String, CallCredentials> callCredentialsCache =

xds/src/main/java/io/grpc/xds/RouterFilter.java

@@ -18,7 +18,6 @@
 
 import com.google.protobuf.Message;
 import io.grpc.ClientInterceptor;
-import io.grpc.LoadBalancer.PickSubchannelArgs;
 import io.grpc.ServerInterceptor;
 import io.grpc.xds.Filter.ClientInterceptorBuilder;
 import io.grpc.xds.Filter.ServerInterceptorBuilder;
@@ -64,7 +63,7 @@ public ConfigOrError<? extends FilterConfig> parseFilterConfigOverride(Message r
   @Nullable
   @Override
   public ClientInterceptor buildClientInterceptor(
-      FilterConfig config, @Nullable FilterConfig overrideConfig, PickSubchannelArgs args,
+      FilterConfig config, @Nullable FilterConfig overrideConfig,
       ScheduledExecutorService scheduler) {
     return null;
   }