Add order to client props customizer

Sets the `@Order` attribute on the ClientPropertiesChannelBuilderCustomizer
which allows users to order their customizers before or after the client
props customizer.

Also adds order to the de/compressor channel builder customizers.

Fixes #359

Signed-off-by: onobc <chris.bono@gmail.com>

Author: onobc

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

@@ -28,6 +28,7 @@
 import org.springframework.context.annotation.Bean;
 import org.springframework.context.annotation.Configuration;
 import org.springframework.context.annotation.Import;
+import org.springframework.core.annotation.Order;
 import org.springframework.grpc.client.ChannelCredentialsProvider;
 import org.springframework.grpc.client.ClientInterceptorsConfigurer;
 import org.springframework.grpc.client.CoroutineStubFactory;
@@ -46,6 +47,26 @@
 		GrpcChannelFactoryConfigurations.InProcessChannelFactoryConfiguration.class, ClientScanConfiguration.class })
 public final class GrpcClientAutoConfiguration {
 
+	/**
+	 * Order applied to the {@link ClientPropertiesChannelBuilderCustomizer} used to apply
+	 * {@link GrpcClientProperties} to channel builders.
+	 */
+	public static final int CLIENT_PROPS_CHANNEL_BUILDER_CUSTOMIZER_ORDER = 0;
+
+	/**
+	 * Order applied to the {@link GrpcChannelBuilderCustomizer
+	 * compressionClientCustomizer} used to set the compressor registry on the channel
+	 * builder.
+	 */
+	public static final int COMPRESSION_CHANNEL_BUILDER_CUSTOMIZER_ORDER = 1;
+
+	/**
+	 * Order applied to the {@link GrpcChannelBuilderCustomizer
+	 * decompressionClientCustomizer} used to set the decompressor registry on the channel
+	 * builder.
+	 */
+	public static final int DECOMPRESSION_CHANNEL_BUILDER_CUSTOMIZER_ORDER = 2;
+
 	@Bean
 	@ConditionalOnMissingBean
 	ClientInterceptorsConfigurer clientInterceptorsConfigurer(ApplicationContext applicationContext) {
@@ -59,20 +80,23 @@ NamedChannelCredentialsProvider channelCredentialsProvider(SslBundles bundles, G
 	}
 
 	@Bean
+	@Order(CLIENT_PROPS_CHANNEL_BUILDER_CUSTOMIZER_ORDER)
 	<T extends ManagedChannelBuilder<T>> GrpcChannelBuilderCustomizer<T> clientPropertiesChannelCustomizer(
 			GrpcClientProperties properties) {
 		return new ClientPropertiesChannelBuilderCustomizer<>(properties);
 	}
 
 	@ConditionalOnBean(CompressorRegistry.class)
 	@Bean
+	@Order(COMPRESSION_CHANNEL_BUILDER_CUSTOMIZER_ORDER)
 	<T extends ManagedChannelBuilder<T>> GrpcChannelBuilderCustomizer<T> compressionClientCustomizer(
 			CompressorRegistry registry) {
 		return (name, builder) -> builder.compressorRegistry(registry);
 	}
 
 	@ConditionalOnBean(DecompressorRegistry.class)
 	@Bean
+	@Order(DECOMPRESSION_CHANNEL_BUILDER_CUSTOMIZER_ORDER)
 	<T extends ManagedChannelBuilder<T>> GrpcChannelBuilderCustomizer<T> decompressionClientCustomizer(
 			DecompressorRegistry registry) {
 		return (name, builder) -> builder.decompressorRegistry(registry);

spring-grpc-client-spring-boot-autoconfigure/src/test/java/org/springframework/boot/grpc/client/autoconfigure/GrpcClientAutoConfigurationTests.java

@@ -48,6 +48,7 @@
 import org.springframework.grpc.client.InProcessGrpcChannelFactory;
 import org.springframework.grpc.client.NettyGrpcChannelFactory;
 import org.springframework.grpc.client.ShadedNettyGrpcChannelFactory;
+import org.springframework.test.util.ReflectionTestUtils;
 
 import io.grpc.Codec;
 import io.grpc.CompressorRegistry;
@@ -230,6 +231,21 @@ void channelBuilderCustomizersAutoConfiguredAsExpected() {
 						ChannelBuilderCustomizersConfig.CUSTOMIZER_FOO));
 	}
 
+	@Test
+	void userDefinedCustomizerCanRunBeforeAndAfterClientPropsCustomizer() {
+		this.contextRunner().withUserConfiguration(UserClientPropsCustomizerConfig.class).run((context) -> {
+			// NOTE: AssertJ "extract list + satisfies" balks about generic types
+			// so we have to do this the old fashion way.
+			var clientPropsCustomizer = context.getBean(ClientPropertiesChannelBuilderCustomizer.class);
+			var channelBuilderCustomizers = context.getBean(ChannelBuilderCustomizers.class);
+			List<GrpcChannelBuilderCustomizer<?>> customizers = (List<GrpcChannelBuilderCustomizer<?>>) ReflectionTestUtils
+				.getField(channelBuilderCustomizers, "customizers");
+			assertThat(customizers).isNotNull();
+			assertThat(customizers).containsSequence(UserClientPropsCustomizerConfig.CUSTOMIZER_PRE_CLIENT_PROPS,
+					clientPropsCustomizer, UserClientPropsCustomizerConfig.CUSTOMIZER_POST_CLIENT_PROPS);
+		});
+	}
+
 	@Test
 	void clientScanConfigurationAutoConfiguredAsExpected() {
 		this.contextRunner().run((context) -> assertThat(context).hasSingleBean(ClientScanConfiguration.class));
@@ -447,4 +463,25 @@ GrpcChannelBuilderCustomizer<?> customizerBar() {
 
 	}
 
+	@Configuration(proxyBeanMethods = false)
+	static class UserClientPropsCustomizerConfig {
+
+		static GrpcChannelBuilderCustomizer<?> CUSTOMIZER_PRE_CLIENT_PROPS = mock();
+
+		static GrpcChannelBuilderCustomizer<?> CUSTOMIZER_POST_CLIENT_PROPS = mock();
+
+		@Bean
+		@Order(GrpcClientAutoConfiguration.CLIENT_PROPS_CHANNEL_BUILDER_CUSTOMIZER_ORDER - 1)
+		GrpcChannelBuilderCustomizer<?> customizerFoo() {
+			return CUSTOMIZER_PRE_CLIENT_PROPS;
+		}
+
+		@Bean
+		@Order(GrpcClientAutoConfiguration.CLIENT_PROPS_CHANNEL_BUILDER_CUSTOMIZER_ORDER + 1)
+		GrpcChannelBuilderCustomizer<?> customizerBar() {
+			return CUSTOMIZER_POST_CLIENT_PROPS;
+		}
+
+	}
+
 }