[BREAKING] Simplify interceptor registry (Fixes #338)

- Lazy collect interceptors and global interceptor configurers
- Changed API of global interceptor registry and configurers

Now it is possible to define a global interceptor using the respective
annotation in a @configuration. It is no longer required for (auto)
configs with global interceptor and their configurers to be loaded
before the grpc channel/server auto config.

Author: ST-DDT

docs/en/client/configuration.md

@@ -128,8 +128,8 @@ public GrpcChannelConfigurer keepAliveClientConfigurer() {
 
 There are three ways to add a `ClientInterceptor` to your channel.
 
-- Define the `ClientInterceptor` as a global interceptor using either the `@GrpcGlobalClientInterceptor` annotation or
-  the `GlobalClientInterceptorRegistry`
+- Define the `ClientInterceptor` as a global interceptor using either the `@GrpcGlobalClientInterceptor` annotation,
+  or a `GlobalClientInterceptorConfigurer`
 - Explicitly list them in the `@GrpcClient#interceptors` or `@GrpcClient#interceptorNames` field
 - Use a `StubTransformer` and call `stub.withInterceptors(ClientInterceptor... interceptors)`
 

docs/en/server/configuration.md

@@ -10,6 +10,7 @@ This section describes how you can configure your grpc-spring-boot-starter appli
   - [Changing the Server Port](#changing-the-server-port)
   - [Enabling the InProcessServer](#enabling-the-inprocessserver)
 - [Configuration via Beans](#configuration-via-beans)
+  - [ServerInterceptor](#serverinterceptor)
   - [GrpcServerConfigurer](#grpcserverconfigurer)
 
 ## Additional topics <!-- omit in toc -->
@@ -86,6 +87,15 @@ First of all most of the beans can be replaced by custom ones, that you can conf
 If you don't wish to go that far, you can use classes such as `GrpcServerConfigurer` to configure the server and other
 components without losing the features provided by this library.
 
+### ServerInterceptor
+
+There are three ways to add a `ServerInterceptor` to your server.
+
+- Define the `ServerInterceptor` as a global interceptor using either the `@GrpcGlobalServerInterceptor` annotation,
+  or a `GlobalServerInterceptorConfigurer`
+- Explicitly list them in the `@GrpcService#interceptors` or `@GrpcService#interceptorNames` field
+- Use a `GrpcServerConfigurer` and call `serverBuilder.intercept(ServerInterceptor interceptor)`
+
 ### GrpcServerConfigurer
 
 The grpc server configurer allows you to add your custom configuration to grpc's `ServerBuilder`s.

examples/cloud-grpc-client/src/main/java/net/devh/boot/grpc/examples/cloud/client/GlobalClientInterceptorConfiguration.java

@@ -22,15 +22,15 @@
 import org.springframework.core.Ordered;
 import org.springframework.core.annotation.Order;
 
-import net.devh.boot.grpc.client.interceptor.GlobalClientInterceptorConfigurer;
+import io.grpc.ClientInterceptor;
 
 @Order(Ordered.LOWEST_PRECEDENCE)
 @Configuration(proxyBeanMethods = false)
 public class GlobalClientInterceptorConfiguration {
 
     @Bean
-    public GlobalClientInterceptorConfigurer globalInterceptorConfigurerAdapter() {
-        return registry -> registry.addClientInterceptors(new LogGrpcInterceptor());
+    ClientInterceptor logClientInterceptor() {
+        return new LogGrpcInterceptor();
     }
 
 }

examples/cloud-grpc-server/src/main/java/net/devh/boot/grpc/examples/cloud/server/GlobalInterceptorConfiguration.java

@@ -17,17 +17,17 @@
 
 package net.devh.boot.grpc.examples.cloud.server;
 
-import org.springframework.context.annotation.Bean;
 import org.springframework.context.annotation.Configuration;
 
-import net.devh.boot.grpc.server.interceptor.GlobalServerInterceptorConfigurer;
+import io.grpc.ServerInterceptor;
+import net.devh.boot.grpc.server.interceptor.GrpcGlobalServerInterceptor;
 
 @Configuration(proxyBeanMethods = false)
 public class GlobalInterceptorConfiguration {
 
-    @Bean
-    public GlobalServerInterceptorConfigurer globalInterceptorConfigurerAdapter() {
-        return registry -> registry.addServerInterceptors(new LogGrpcInterceptor());
+    @GrpcGlobalServerInterceptor
+    ServerInterceptor logServerInterceptor() {
+        return new LogGrpcInterceptor();
     }
 
 }

examples/local-grpc-client/src/main/java/net/devh/boot/grpc/examples/local/client/GlobalClientInterceptorConfiguration.java

@@ -22,15 +22,15 @@
 import org.springframework.core.Ordered;
 import org.springframework.core.annotation.Order;
 
-import net.devh.boot.grpc.client.interceptor.GlobalClientInterceptorConfigurer;
+import io.grpc.ClientInterceptor;
 
 @Order(Ordered.LOWEST_PRECEDENCE)
 @Configuration(proxyBeanMethods = false)
 public class GlobalClientInterceptorConfiguration {
 
     @Bean
-    public GlobalClientInterceptorConfigurer globalInterceptorConfigurerAdapter() {
-        return registry -> registry.addClientInterceptors(new LogGrpcInterceptor());
+    ClientInterceptor logClientInterceptor() {
+        return new LogGrpcInterceptor();
     }
 
 }

examples/local-grpc-server/src/main/java/net/devh/boot/grpc/examples/local/server/GlobalInterceptorConfiguration.java

@@ -17,23 +17,17 @@
 
 package net.devh.boot.grpc.examples.local.server;
 
-import org.springframework.context.annotation.Bean;
 import org.springframework.context.annotation.Configuration;
 
-import net.devh.boot.grpc.server.interceptor.GlobalServerInterceptorConfigurer;
-import net.devh.boot.grpc.server.interceptor.GlobalServerInterceptorRegistry;
+import io.grpc.ServerInterceptor;
+import net.devh.boot.grpc.server.interceptor.GrpcGlobalServerInterceptor;
 
 @Configuration(proxyBeanMethods = false)
 public class GlobalInterceptorConfiguration {
 
-    @Bean
-    public GlobalServerInterceptorConfigurer globalInterceptorConfigurerAdapter() {
-        return new GlobalServerInterceptorConfigurer() {
-            @Override
-            public void addServerInterceptors(GlobalServerInterceptorRegistry registry) {
-                registry.addServerInterceptors(new LogGrpcInterceptor());
-            }
-        };
+    @GrpcGlobalServerInterceptor
+    ServerInterceptor logServerInterceptor() {
+        return new LogGrpcInterceptor();
     }
 
 }

grpc-client-spring-boot-autoconfigure/src/main/java/net/devh/boot/grpc/client/autoconfigure/GrpcClientAutoConfiguration.java

@@ -92,13 +92,15 @@ GrpcChannelsProperties grpcChannelsProperties() {
 
     @ConditionalOnMissingBean
     @Bean
-    GlobalClientInterceptorRegistry globalClientInterceptorRegistry() {
-        return new GlobalClientInterceptorRegistry();
+    GlobalClientInterceptorRegistry globalClientInterceptorRegistry(final ApplicationContext applicationContext) {
+        return new GlobalClientInterceptorRegistry(applicationContext);
     }
 
     @Bean
-    AnnotationGlobalClientInterceptorConfigurer annotationGlobalClientInterceptorConfigurer() {
-        return new AnnotationGlobalClientInterceptorConfigurer();
+    @Lazy
+    AnnotationGlobalClientInterceptorConfigurer annotationGlobalClientInterceptorConfigurer(
+            final ApplicationContext applicationContext) {
+        return new AnnotationGlobalClientInterceptorConfigurer(applicationContext);
     }
 
     /**

grpc-client-spring-boot-autoconfigure/src/main/java/net/devh/boot/grpc/client/autoconfigure/GrpcClientTraceAutoConfiguration.java

@@ -20,11 +20,11 @@
 import org.springframework.boot.autoconfigure.AutoConfigureAfter;
 import org.springframework.boot.autoconfigure.condition.ConditionalOnBean;
 import org.springframework.boot.autoconfigure.condition.ConditionalOnProperty;
-import org.springframework.context.annotation.Bean;
 import org.springframework.context.annotation.Configuration;
 
 import brave.grpc.GrpcTracing;
-import net.devh.boot.grpc.client.interceptor.GlobalClientInterceptorConfigurer;
+import io.grpc.ClientInterceptor;
+import net.devh.boot.grpc.client.interceptor.GrpcGlobalClientInterceptor;
 import net.devh.boot.grpc.client.interceptor.OrderedClientInterceptor;
 import net.devh.boot.grpc.common.autoconfigure.GrpcCommonTraceAutoConfiguration;
 import net.devh.boot.grpc.common.util.InterceptorOrder;
@@ -44,14 +44,13 @@ public class GrpcClientTraceAutoConfiguration {
      * Configures a global client interceptor that applies brave's tracing logic to the requests.
      *
      * @param grpcTracing The grpc tracing bean.
-     * @return The globalTraceClientInterceptorConfigurer bean.
+     * @return The tracing client interceptor bean.
      */
-    @Bean
-    public GlobalClientInterceptorConfigurer globalTraceClientInterceptorConfigurer(final GrpcTracing grpcTracing) {
-        return registry -> registry.addClientInterceptors(
-                new OrderedClientInterceptor(
-                        grpcTracing.newClientInterceptor(),
-                        InterceptorOrder.ORDER_TRACING_METRICS + 1));
+    @GrpcGlobalClientInterceptor
+    ClientInterceptor globalTraceClientInterceptorConfigurer(final GrpcTracing grpcTracing) {
+        return new OrderedClientInterceptor(
+                grpcTracing.newClientInterceptor(),
+                InterceptorOrder.ORDER_TRACING_METRICS + 1);
     }
 
 }

grpc-client-spring-boot-autoconfigure/src/main/java/net/devh/boot/grpc/client/interceptor/AnnotationGlobalClientInterceptorConfigurer.java

@@ -17,7 +17,13 @@
 
 package net.devh.boot.grpc.client.interceptor;
 
-import org.springframework.beans.factory.annotation.Autowired;
+import static com.google.common.collect.Maps.transformValues;
+import static java.util.Objects.requireNonNull;
+
+import java.util.List;
+import java.util.Map;
+import java.util.Map.Entry;
+
 import org.springframework.context.ApplicationContext;
 
 import io.grpc.ClientInterceptor;
@@ -31,17 +37,36 @@
 @Slf4j
 public class AnnotationGlobalClientInterceptorConfigurer implements GlobalClientInterceptorConfigurer {
 
-    @Autowired
-    private ApplicationContext context;
+    private final ApplicationContext applicationContext;
+
+    /**
+     * Creates a new AnnotationGlobalClientInterceptorConfigurer.
+     *
+     * @param applicationContext The application context to fetch the {@link GrpcGlobalClientInterceptor} annotated
+     *        {@link ClientInterceptor} beans from.
+     */
+    public AnnotationGlobalClientInterceptorConfigurer(final ApplicationContext applicationContext) {
+        this.applicationContext = requireNonNull(applicationContext, "applicationContext");
+    }
+
+    /**
+     * Helper method used to get the {@link GrpcGlobalClientInterceptor} annotated {@link ClientInterceptor}s from the
+     * application context.
+     *
+     * @return A map containing the global interceptor beans.
+     */
+    protected Map<String, ClientInterceptor> getClientInterceptorBeans() {
+        return transformValues(this.applicationContext.getBeansWithAnnotation(GrpcGlobalClientInterceptor.class),
+                ClientInterceptor.class::cast);
+    }
 
     @Override
-    public void addClientInterceptors(final GlobalClientInterceptorRegistry registry) {
-        this.context.getBeansWithAnnotation(GrpcGlobalClientInterceptor.class)
-                .forEach((name, bean) -> {
-                    ClientInterceptor interceptor = (ClientInterceptor) bean;
-                    log.debug("Registering GlobalClientInterceptor: {} ({})", name, interceptor);
-                    registry.addClientInterceptors(interceptor);
-                });
+    public void configureClientInterceptors(final List<ClientInterceptor> interceptors) {
+        for (final Entry<String, ClientInterceptor> entry : getClientInterceptorBeans().entrySet()) {
+            final ClientInterceptor interceptor = entry.getValue();
+            log.debug("Registering GlobalClientInterceptor: {} ({})", entry.getKey(), interceptor);
+            interceptors.add(interceptor);
+        }
     }
 
 }

grpc-client-spring-boot-autoconfigure/src/main/java/net/devh/boot/grpc/client/interceptor/GlobalClientInterceptorConfigurer.java

@@ -17,21 +17,24 @@
 
 package net.devh.boot.grpc.client.interceptor;
 
+import java.util.List;
+
 import io.grpc.ClientInterceptor;
 
 /**
- * This configurer can be used to register new global {@link ClientInterceptor}s.
+ * A bean that can be used to configure global {@link ClientInterceptor}s.
  *
  * @author Daniel Theuke ([email protected])
  */
 @FunctionalInterface
 public interface GlobalClientInterceptorConfigurer {
 
     /**
-     * Adds the {@link ClientInterceptor}s that should be registered globally to the given registry.
+     * Configures the given list of client interceptors, possibly adding new elements, removing unwanted elements, or
+     * reordering the existing ones.
      *
-     * @param registry The registry the interceptors should be added to.
+     * @param interceptors A mutable list of client interceptors to configure.
      */
-    void addClientInterceptors(GlobalClientInterceptorRegistry registry);
+    void configureClientInterceptors(List<ClientInterceptor> interceptors);
 
 }