Improve error handling for service injection

kaklakariada · kaklakariada · commit 25fdfbb0536b · 2018-07-15T18:15:06.000+02:00
diff --git a/src/main/java/com/github/kaklakariada/aws/lambda/RequestHandlingService.java b/src/main/java/com/github/kaklakariada/aws/lambda/RequestHandlingService.java
@@ -65,7 +65,10 @@ public static <P extends ServiceParams> RequestHandlingService create(LambdaCont
 					serviceFactory);
 			listeners.add(serviceParamsSupplier);
 			final Injector<P> injector = new Injector<>(new ServiceCache<>(serviceFactory), serviceParamsSupplier);
+			LOG.debug("Injecting services into controller {} using service factory {}", controller, serviceFactory);
 			injector.injectServices(controller);
+		} else {
+			LOG.debug("No service factory available, don't inject services");
 		}
 		final ObjectMapper objectMapper = createObjectMapper();
 		final ControllerAdapter adapter = ControllerAdapter.create(objectMapper, controller);
@@ -102,7 +105,7 @@ private ApiGatewayResponse handleRequest(final ApiGatewayRequest request, Contex
 			final String responseBody = serializeResult(result);
 			return ApiGatewayResponse.ok(responseBody);
 		} catch (final LambdaException e) {
-			LOG.error("Error processing request: {}", e.getMessage());
+			LOG.error("Error processing request: {}", e.getMessage(), e);
 			return buildErrorResponse(e, context);
 		} catch (final Exception e) {
 			LOG.error("Error processing request: " + e.getMessage(), e);
diff --git a/src/main/java/com/github/kaklakariada/aws/lambda/inject/Injector.java b/src/main/java/com/github/kaklakariada/aws/lambda/inject/Injector.java
@@ -25,12 +25,17 @@
 
 import javax.inject.Inject;
 
+import org.slf4j.Logger;
+import org.slf4j.LoggerFactory;
+
 import com.github.kaklakariada.aws.lambda.controller.LambdaController;
 import com.github.kaklakariada.aws.lambda.exception.InternalServerErrorException;
 import com.github.kaklakariada.aws.lambda.service.ServiceCache;
 import com.github.kaklakariada.aws.lambda.service.ServiceParams;
 
 public class Injector<P extends ServiceParams> {
+	private static final Logger LOG = LoggerFactory.getLogger(Injector.class);
+
 	private final ServiceCache<P> cache;
 	private final Supplier<P> serviceParams;
 
@@ -42,15 +47,19 @@ public Injector(ServiceCache<P> cache, Supplier<P> serviceParams) {
 	public void injectServices(LambdaController controller) {
 		Arrays.stream(controller.getClass().getDeclaredFields())
 				.filter(field -> field.getAnnotation(Inject.class) != null) //
-				.filter(field -> field.getType().equals(Supplier.class)) //
 				.forEach(field -> inject(controller, field));
 	}
 
 	private void inject(LambdaController controller, Field field) {
+		if (!field.getType().equals(Supplier.class)) {
+			throw new IllegalStateException("Field " + field.getName() + " has unsupported type "
+					+ field.getType().getName() + ", only Supplier is supported");
+		}
 		final ParameterizedType type = (ParameterizedType) field.getGenericType();
 		assert type.getActualTypeArguments().length == 1;
 		final Type typeToInject = type.getActualTypeArguments()[0];
 		final Supplier<?> serviceSupplier = getServiceSupplier((Class<?>) typeToInject);
+		LOG.debug("Injecting supplier of type {} into field {}", typeToInject.getTypeName(), field.getName());
 		inject(controller, field, serviceSupplier);
 	}
 
diff --git a/src/test/java/com/github/kaklakariada/aws/lambda/example/MyLambdaControllerWithUnsupportedServiceType.java b/src/test/java/com/github/kaklakariada/aws/lambda/example/MyLambdaControllerWithUnsupportedServiceType.java
@@ -0,0 +1,34 @@
+/**
+ * aws-lambda-request-handler - Request handler for AWS Lambda Proxy model
+ * Copyright (C) 2017 Christoph Pirkl <christoph at users.sourceforge.net>
+ *
+ * This program is free software: you can redistribute it and/or modify
+ * it under the terms of the GNU General Public License as published by
+ * the Free Software Foundation, either version 3 of the License, or
+ * (at your option) any later version.
+ *
+ * This program is distributed in the hope that it will be useful,
+ * but WITHOUT ANY WARRANTY; without even the implied warranty of
+ * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
+ * GNU General Public License for more details.
+ *
+ * You should have received a copy of the GNU General Public License
+ * along with this program. If not, see <http://www.gnu.org/licenses/>.
+ */
+package com.github.kaklakariada.aws.lambda.example;
+
+import javax.inject.Inject;
+
+import com.github.kaklakariada.aws.lambda.controller.LambdaController;
+import com.github.kaklakariada.aws.lambda.controller.RequestHandlerMethod;
+
+public class MyLambdaControllerWithUnsupportedServiceType implements LambdaController {
+
+	@Inject
+	private MyServiceB serviceB;
+
+	@RequestHandlerMethod
+	public String handleRequest() {
+		return "Service B: " + serviceB.getValue();
+	}
+}
diff --git a/src/test/java/com/github/kaklakariada/aws/lambda/inject/InjectorTest.java b/src/test/java/com/github/kaklakariada/aws/lambda/inject/InjectorTest.java
@@ -17,6 +17,7 @@
  */
 package com.github.kaklakariada.aws.lambda.inject;
 
+import static org.hamcrest.CoreMatchers.containsString;
 import static org.hamcrest.CoreMatchers.equalTo;
 import static org.hamcrest.MatcherAssert.assertThat;
 import static org.junit.jupiter.api.Assertions.assertThrows;
@@ -30,6 +31,7 @@
 import org.mockito.MockitoAnnotations;
 
 import com.github.kaklakariada.aws.lambda.example.MyLambdaController;
+import com.github.kaklakariada.aws.lambda.example.MyLambdaControllerWithUnsupportedServiceType;
 import com.github.kaklakariada.aws.lambda.example.MyServiceB;
 import com.github.kaklakariada.aws.lambda.example.MyServiceParams;
 import com.github.kaklakariada.aws.lambda.service.ServiceCache;
@@ -79,6 +81,14 @@ public void testServiceInjectedIntoController() {
 		assertThat(controller.handleRequest(), equalTo("Service B: " + VALUE2));
 	}
 
+	@Test
+	public void testUnsupportedServiceTypeInjected() {
+		final IllegalStateException exception = assertThrows(IllegalStateException.class,
+				() -> injector.injectServices(new MyLambdaControllerWithUnsupportedServiceType()));
+		assertThat(exception.getMessage(), containsString(
+				"Field serviceB has unsupported type com.github.kaklakariada.aws.lambda.example.MyServiceB, only Supplier is supported"));
+	}
+
 	@Test
 	public void testServiceParamsSupplierReturnsNull() {
 		injector.injectServices(controller);
diff --git a/test-project/src/main/java/handler/echo/EchoHandler.java b/test-project/src/main/java/handler/echo/EchoHandler.java
@@ -20,6 +20,7 @@ public EchoHandler() {
 	}
 
 	public static class EchoController implements LambdaController {
+
 		@RequestHandlerMethod
 		public EchoResponse handleRequest(@RequestBody EchoRequest body, Context context, ApiGatewayRequest request,
 				@HeaderValue("User-Agent") String userAgent) {
diff --git a/test-project/src/main/java/handler/echo/ServiceBasedEchoHandler.java b/test-project/src/main/java/handler/echo/ServiceBasedEchoHandler.java
@@ -0,0 +1,36 @@
+package handler.echo;
+
+import java.util.function.Supplier;
+
+import javax.inject.Inject;
+
+import org.slf4j.Logger;
+import org.slf4j.LoggerFactory;
+
+import com.github.kaklakariada.aws.lambda.LambdaRequestHandler;
+import com.github.kaklakariada.aws.lambda.controller.LambdaController;
+import com.github.kaklakariada.aws.lambda.controller.RequestHandlerMethod;
+import com.github.kaklakariada.aws.lambda.model.request.ApiGatewayRequest;
+
+import handler.service.EchoServiceFactory;
+import handler.service.StageBasedEchoService;
+
+public class ServiceBasedEchoHandler extends LambdaRequestHandler {
+
+	private static final Logger LOG = LoggerFactory.getLogger(ServiceBasedEchoHandler.class);
+
+	public ServiceBasedEchoHandler() {
+		super(new ServiceBasedEchoController(), new EchoServiceFactory());
+	}
+
+	public static class ServiceBasedEchoController implements LambdaController {
+		@Inject
+		private Supplier<StageBasedEchoService> echoService;
+
+		@RequestHandlerMethod
+		public String echo(ApiGatewayRequest request) {
+			LOG.info("Code uri: {}", echoService.get().getCodeUri());
+			return echoService.get().echo(request.getPath());
+		}
+	}
+}
diff --git a/test-project/src/main/java/handler/service/EchoServiceFactory.java b/test-project/src/main/java/handler/service/EchoServiceFactory.java
@@ -0,0 +1,21 @@
+package handler.service;
+
+import java.util.Map;
+
+import com.github.kaklakariada.aws.lambda.model.request.ApiGatewayRequest;
+import com.github.kaklakariada.aws.lambda.service.ServiceFactory;
+import com.github.kaklakariada.aws.lambda.service.ServiceRegistry;
+
+public class EchoServiceFactory implements ServiceFactory<EchoServiceParam> {
+
+	@Override
+	public EchoServiceParam extractServiceParams(ApiGatewayRequest request, Map<String, String> env) {
+		return new EchoServiceParam(request.getStageVariable("stage"), env.get("CODE_URI"));
+	}
+
+	@Override
+	public void registerServices(ServiceRegistry registry, EchoServiceParam params) {
+		registry.addService(StageBasedEchoService.class,
+				() -> new StageBasedEchoService(params.getStage(), params.getCodeUri()));
+	}
+}
diff --git a/test-project/src/main/java/handler/service/EchoServiceParam.java b/test-project/src/main/java/handler/service/EchoServiceParam.java
@@ -0,0 +1,59 @@
+package handler.service;
+
+import com.github.kaklakariada.aws.lambda.service.ServiceParams;
+
+public class EchoServiceParam implements ServiceParams {
+	private final String stage;
+	private final String codeUri;
+
+	public EchoServiceParam(String stage, String codeUri) {
+		this.stage = stage;
+		this.codeUri = codeUri;
+	}
+
+	public String getStage() {
+		return stage;
+	}
+
+	public String getCodeUri() {
+		return codeUri;
+	}
+
+	@Override
+	public int hashCode() {
+		final int prime = 31;
+		int result = 1;
+		result = prime * result + ((codeUri == null) ? 0 : codeUri.hashCode());
+		result = prime * result + ((stage == null) ? 0 : stage.hashCode());
+		return result;
+	}
+
+	@Override
+	public boolean equals(Object obj) {
+		if (this == obj) {
+			return true;
+		}
+		if (obj == null) {
+			return false;
+		}
+		if (getClass() != obj.getClass()) {
+			return false;
+		}
+		final EchoServiceParam other = (EchoServiceParam) obj;
+		if (codeUri == null) {
+			if (other.codeUri != null) {
+				return false;
+			}
+		} else if (!codeUri.equals(other.codeUri)) {
+			return false;
+		}
+		if (stage == null) {
+			if (other.stage != null) {
+				return false;
+			}
+		} else if (!stage.equals(other.stage)) {
+			return false;
+		}
+		return true;
+	}
+}
diff --git a/test-project/src/main/java/handler/service/StageBasedEchoService.java b/test-project/src/main/java/handler/service/StageBasedEchoService.java
@@ -0,0 +1,19 @@
+package handler.service;
+
+public class StageBasedEchoService {
+	private final String stage;
+	private final String codeUri;
+
+	public StageBasedEchoService(String stage, String codeUri) {
+		this.stage = stage;
+		this.codeUri = codeUri;
+	}
+
+	public String echo(String message) {
+		return "Stage " + stage + ": " + message;
+	}
+
+	public String getCodeUri() {
+		return codeUri;
+	}
+}
diff --git a/test-project/src/main/resources/log4j2.xml b/test-project/src/main/resources/log4j2.xml
@@ -11,5 +11,6 @@
         <Root level="info">
             <AppenderRef ref="Lambda" />
         </Root>
+        <Logger name="com.github.kaklakariada" level="trace" />
     </Loggers>
 </Configuration>
diff --git a/test-project/template.yml b/test-project/template.yml
@@ -30,6 +30,19 @@ Resources:
                 uri:
                   Fn::Sub: arn:aws:apigateway:${AWS::Region}:lambda:path/2015-03-31/functions/${EchoFunction.Arn}/invocations
 
+          /echoservice:
+            get:
+              description: Returns an echo
+              responses:
+                default:
+                  statusCode: 200
+              x-amazon-apigateway-integration:
+                passthroughBehavior: when_no_match
+                httpMethod: POST
+                type: aws_proxy
+                uri:
+                  Fn::Sub: arn:aws:apigateway:${AWS::Region}:lambda:path/2015-03-31/functions/${ServiceBasedEchoFunction.Arn}/invocations
+
           /echo/{id}/echo:
             get:
               description: Returns an echo by id
@@ -59,6 +72,24 @@ Resources:
             Path: /echo
             Method: GET
 
+  ServiceBasedEchoFunction:
+    Type: AWS::Serverless::Function
+    Properties:
+      Handler: handler.echo.ServiceBasedEchoHandler
+      Runtime: java8
+      Timeout: 15
+      Environment:
+        Variables:
+          CODE_URI: ${CodeUri}
+      CodeUri: ${CodeUri}
+      Events:
+        GetRequest:
+          Type: Api
+          Properties:
+            RestApiId: !Ref ApiGatewayApi
+            Path: /echoservice
+            Method: GET
+
   EchoWithPathFunction:
     Type: AWS::Serverless::Function
     Properties:

Original file line number	Diff line number	Diff line change
`@@ -20,6 +20,7 @@ public EchoHandler() {`
`20`	`20`	`}`
`21`	`21`
`22`	`22`	`public static class EchoController implements LambdaController {`
	`23`	`+`
`23`	`24`	`@RequestHandlerMethod`
`24`	`25`	`public EchoResponse handleRequest(@RequestBody EchoRequest body, Context context, ApiGatewayRequest request,`
`25`	`26`	`@HeaderValue("User-Agent") String userAgent) {`