Add channel configurers (global beans)

spring-grpc-core/src/main/java/org/springframework/grpc/client/DefaultGrpcChannelFactory.java

@@ -16,6 +16,7 @@
 package org.springframework.grpc.client;
 
 import java.util.ArrayList;
+import java.util.List;
 import java.util.Map;
 import java.util.concurrent.ConcurrentHashMap;
 
@@ -29,11 +30,23 @@ import io.grpc.ManagedChannelBuilder;
 
 public class DefaultGrpcChannelFactory implements GrpcChannelFactory, DisposableBean {
 
-	private Map<String, ManagedChannel> channels = new ConcurrentHashMap<>();
+	private final Map<String, ManagedChannel> channels = new ConcurrentHashMap<>();
+
+	private final List<GrpcChannelConfigurer> configurers = new ArrayList<>();
+
+	public DefaultGrpcChannelFactory() {
+	}
+
+	public DefaultGrpcChannelFactory(List<GrpcChannelConfigurer> configurers) {
+		configurers.addAll(configurers);
+	}
 
 	@Override
 	public ManagedChannelBuilder<?> createChannel(String authority) {
 		ManagedChannelBuilder<?> target = Grpc.newChannelBuilder(authority, InsecureChannelCredentials.create());
+		for (GrpcChannelConfigurer configurer : configurers) {
+			configurer.accept(target);
+		}
 		return new DisposableChannelBuilder(authority, target);
 	}
 

spring-grpc-spring-boot-autoconfigure/src/main/java/org/springframework/grpc/autoconfigure/client/GrpcClientAutoConfiguration.java

@@ -15,10 +15,13 @@
  */
 package org.springframework.grpc.autoconfigure.client;
 
+import java.util.List;
+
 import org.springframework.boot.autoconfigure.condition.ConditionalOnMissingBean;
 import org.springframework.context.annotation.Bean;
 import org.springframework.context.annotation.Configuration;
 import org.springframework.grpc.client.DefaultGrpcChannelFactory;
+import org.springframework.grpc.client.GrpcChannelConfigurer;
 import org.springframework.grpc.client.GrpcChannelFactory;
 
 @Configuration(proxyBeanMethods = false)
@@ -26,8 +29,8 @@ public class GrpcClientAutoConfiguration {
 
 	@Bean
 	@ConditionalOnMissingBean(GrpcChannelFactory.class)
-	public DefaultGrpcChannelFactory defaultGrpcChannelFactory() {
-		return new DefaultGrpcChannelFactory();
+	public DefaultGrpcChannelFactory defaultGrpcChannelFactory(final List<GrpcChannelConfigurer> configurers) {
+		return new DefaultGrpcChannelFactory(configurers);
 	}
 
 }