GH-789 Propagate AWS FunctionInvoker exceptions

They will be handled by the AWS runtime and properly reported and recorded.
Resolves #789

spring-cloud-function-adapters/spring-cloud-function-adapter-aws/src/main/java/org/springframework/cloud/function/adapter/aws/FunctionInvoker.java

@@ -30,7 +30,6 @@ import java.util.Set;
 
 import com.amazonaws.services.lambda.runtime.Context;
 import com.amazonaws.services.lambda.runtime.RequestStreamHandler;
-import com.amazonaws.services.lambda.runtime.events.APIGatewayProxyResponseEvent;
 import com.fasterxml.jackson.core.JsonParser;
 import com.fasterxml.jackson.databind.DeserializationContext;
 import com.fasterxml.jackson.databind.JsonDeserializer;
@@ -53,7 +52,6 @@ import org.springframework.cloud.function.utils.FunctionClassUtils;
 import org.springframework.context.ApplicationContextInitializer;
 import org.springframework.context.ConfigurableApplicationContext;
 import org.springframework.core.env.Environment;
-import org.springframework.http.HttpStatus;
 import org.springframework.messaging.Message;
 import org.springframework.messaging.MessageHeaders;
 import org.springframework.messaging.support.MessageBuilder;
@@ -112,27 +110,10 @@ public class FunctionInvoker implements RequestStreamHandler {
 					.generateMessage(payload, new MessageHeaders(Collections.emptyMap()), function.getInputType(), this.jsonMapper, context);
 		}
 
-		try {
+		Object response = this.function.apply(requestMessage);
-			Object response = this.function.apply(requestMessage);
+		byte[] responseBytes = this.buildResult(requestMessage, response);
-			byte[] responseBytes = this.buildResult(requestMessage, response);
+		StreamUtils.copy(responseBytes, output);
-			StreamUtils.copy(responseBytes, output);
+		// any exception should propagate
-		}
-		catch (Exception e) {
-			logger.error(e);
-			StreamUtils.copy(this.buildExceptionResult(requestMessage, e, isApiGateway), output);
-		}
-	}
-
-	private byte[] buildExceptionResult(Message<?> requestMessage, Exception exception, boolean isApiGateway) throws IOException {
-		if (isApiGateway) {
-			APIGatewayProxyResponseEvent event = new APIGatewayProxyResponseEvent();
-			event.setStatusCode(HttpStatus.EXPECTATION_FAILED.value());
-			event.setBody(exception.getMessage());
-			return this.jsonMapper.toJson(event);
-		}
-		else {
-			throw new IllegalStateException(exception);
-		}
 	}
 
 	@SuppressWarnings("unchecked")

spring-cloud-function-adapters/spring-cloud-function-adapter-aws/src/test/java/org/springframework/cloud/function/adapter/aws/FunctionInvokerTests.java

@@ -49,6 +49,7 @@ import org.springframework.messaging.converter.AbstractMessageConverter;
 import org.springframework.util.MimeType;
 
 import static org.assertj.core.api.Assertions.assertThat;
+import static org.junit.jupiter.api.Assertions.fail;
 
 /**
  *
@@ -914,9 +915,14 @@ public class FunctionInvokerTests {
 
 		InputStream targetStream = new ByteArrayInputStream(this.apiGatewayEvent.getBytes());
 		ByteArrayOutputStream output = new ByteArrayOutputStream();
-		invoker.handleRequest(targetStream, output, null);
+
-		Map result = mapper.readValue(output.toByteArray(), Map.class);
+		try {
-		assertThat(((String) result.get("body"))).startsWith("Failed to establish route, since neither were provided:");
+			invoker.handleRequest(targetStream, output, null);
+			fail();
+		}
+		catch (Exception e) {
+			// TODO: handle exception
+		}
 	}
 
 	@SuppressWarnings("rawtypes")

spring-cloud-function-samples/function-sample-aws/pom.xml

@@ -37,6 +37,10 @@
 			<groupId>org.springframework.cloud</groupId>
 			<artifactId>spring-cloud-function-web</artifactId>
 		</dependency>
+		<dependency>
+			<groupId>org.springframework.boot</groupId>
+			<artifactId>spring-boot-starter-web</artifactId>
+		</dependency>
 
 		<dependency>
 			<groupId>com.amazonaws</groupId>

spring-cloud-function-samples/function-sample-aws/src/main/java/example/FunctionConfiguration.java

@@ -21,7 +21,7 @@ public class FunctionConfiguration {
 	public Function<String, String> uppercase() {
 		return value -> {
 			if (value.equals("exception")) {
-				throw new RuntimeException("Intentional exception which should result in HTTP 417");
+				throw new RuntimeException("Intentional exception");
 			}
 			else {
 				return value.toUpperCase();