Merge pull request #25 from jimmysmith95/master

Server Interceptor support

Author: jvmlet

grpc-spring-boot-starter-demo/src/main/java/org/lognet/springboot/grpc/demo/DemoInterceptor.java

@@ -0,0 +1,23 @@
+package org.lognet.springboot.grpc.demo;
+
+import io.grpc.Metadata;
+import io.grpc.ServerCall;
+import io.grpc.ServerCallHandler;
+import io.grpc.ServerInterceptor;
+import lombok.extern.slf4j.Slf4j;
+import org.lognet.springboot.grpc.GRpcInterceptor;
+
+/**
+ * Created by jamessmith on 9/7/16.
+ */
+@Slf4j
+@GRpcInterceptor
+public class DemoInterceptor implements ServerInterceptor {
+
+    @Override
+    public <ReqT, RespT> ServerCall.Listener<ReqT> interceptCall(ServerCall<ReqT, RespT> call, Metadata headers,
+                                                                 ServerCallHandler<ReqT, RespT> next) {
+        log.info("Demo interceptor invoked!");
+        return next.startCall(call, headers);
+    }
+}

grpc-spring-boot-starter-demo/src/main/java/org/lognet/springboot/grpc/demo/GreeterApp.java

@@ -17,7 +17,7 @@
 @SpringBootApplication
 public class GreeterApp {
 
-    @GRpcService
+    @GRpcService(interceptors = { DemoInterceptor.class })
     public static class GreeterService extends GreeterGrpc.GreeterImplBase {
         @Override
         public void sayHello(GreeterOuterClass.HelloRequest request, StreamObserver<GreeterOuterClass.HelloReply> responseObserver) {
@@ -32,4 +32,3 @@ public static void main(String[] args) {
     }
 
 }
-

grpc-spring-boot-starter/src/main/java/org/lognet/springboot/grpc/GRpcInterceptor.java

@@ -0,0 +1,19 @@
+package org.lognet.springboot.grpc;
+
+import java.lang.annotation.Documented;
+import java.lang.annotation.ElementType;
+import java.lang.annotation.Retention;
+import java.lang.annotation.RetentionPolicy;
+import java.lang.annotation.Target;
+
+import org.springframework.stereotype.Service;
+
+/**
+ * Created by jamessmith on 9/7/16.
+ */
+@Target(ElementType.TYPE)
+@Retention(RetentionPolicy.RUNTIME)
+@Documented
+@Service
+public @interface GRpcInterceptor {
+}

grpc-spring-boot-starter/src/main/java/org/lognet/springboot/grpc/GRpcServerRunner.java

@@ -1,7 +1,12 @@
 package org.lognet.springboot.grpc;
 
+import java.util.ArrayList;
+import java.util.List;
 import java.util.Optional;
 
+import io.grpc.ServerInterceptor;
+import io.grpc.ServerInterceptors;
+import io.grpc.ServerServiceDefinition;
 import org.lognet.springboot.grpc.autoconfigure.GRpcServerProperties;
 import org.springframework.beans.factory.DisposableBean;
 import org.springframework.beans.factory.annotation.Autowired;
@@ -40,7 +45,9 @@ public void run(String... args) throws Exception {
             if (BindableService.class.isAssignableFrom(grpcService.getClass())) {
 
                 BindableService bindableService = BindableService.class.cast(grpcService);
-                serverBuilder.addService(bindableService);
+
+                ServerServiceDefinition definition = bindInterceptors(bindableService);
+                serverBuilder.addService(definition);
                 log.info("'{}' service has been registered.", bindableService.getClass().getName());
             } else {
                 throw new IllegalArgumentException(String.format("%s should be of type %s" ,grpcService.getClass().getName(), BindableService.class.getName()));
@@ -53,6 +60,27 @@ public void run(String... args) throws Exception {
 
     }
 
+    private ServerServiceDefinition bindInterceptors(BindableService bindableService) {
+        Class<? extends ServerInterceptor>[] interceptorClasses = bindableService.getClass().getAnnotation(GRpcService.class).interceptors();
+
+        if(interceptorClasses.length == 0) {
+            bindableService.bindService();
+        }
+
+        List<ServerInterceptor> interceptors = buildInterceptors(interceptorClasses);
+        return ServerInterceptors.intercept(bindableService, interceptors);
+    }
+
+    private List<ServerInterceptor> buildInterceptors(Class<? extends ServerInterceptor>[] classes) {
+        List<ServerInterceptor> interceptors = new ArrayList<>();
+
+        for(Class<? extends ServerInterceptor> clazz : classes) {
+            interceptors.add(applicationContext.getBean(clazz));
+        }
+
+        return interceptors;
+    }
+
     private void startDaemonAwaitThread() {
         Thread awaitThread = new Thread() {
             @Override

grpc-spring-boot-starter/src/main/java/org/lognet/springboot/grpc/GRpcService.java

@@ -6,6 +6,7 @@
 import java.lang.annotation.RetentionPolicy;
 import java.lang.annotation.Target;
 
+import io.grpc.ServerInterceptor;
 import org.springframework.stereotype.Service;
 
 /**
@@ -19,5 +20,5 @@
 @Documented
 @Service
 public @interface GRpcService {
-
+    Class<? extends ServerInterceptor>[] interceptors() default {};
 }