First version of NonRT RIC Controlpanel

[portal/nonrtric-controlpanel.git] / webapp-backend / src / main / java / org / oransc / portal / nonrtric / controlpanel / controller / CustomResponseEntityExceptionHandler.java

diff --git a/webapp-backend/src/main/java/org/oransc/portal/nonrtric/controlpanel/controller/CustomResponseEntityExceptionHandler.java b/webapp-backend/src/main/java/org/oransc/portal/nonrtric/controlpanel/controller/CustomResponseEntityExceptionHandler.java
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+/*-
+ * ========================LICENSE_START=================================
+ * O-RAN-SC
+ * %%
+ * Copyright (C) 2019 AT&T Intellectual Property
+ * Modifications Copyright (C) 2020 Nordix Foundation
+ * %%
+ * Licensed under the Apache License, Version 2.0 (the "License");
+ * you may not use this file except in compliance with the License.
+ * You may obtain a copy of the License at
+ *
+ *      http://www.apache.org/licenses/LICENSE-2.0
+ *
+ * Unless required by applicable law or agreed to in writing, software
+ * distributed under the License is distributed on an "AS IS" BASIS,
+ * WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
+ * See the License for the specific language governing permissions and
+ * limitations under the License.
+ * ========================LICENSE_END===================================
+ */
+package org.oransc.portal.nonrtric.controlpanel.controller;
+
+import java.lang.invoke.MethodHandles;
+import org.oransc.portal.nonrtric.controlpanel.model.ErrorTransport;
+import org.slf4j.Logger;
+import org.slf4j.LoggerFactory;
+import org.springframework.http.HttpStatus;
+import org.springframework.http.ResponseEntity;
+import org.springframework.web.bind.annotation.ControllerAdvice;
+import org.springframework.web.bind.annotation.ExceptionHandler;
+import org.springframework.web.client.HttpStatusCodeException;
+import org.springframework.web.client.RestClientResponseException;
+import org.springframework.web.context.request.WebRequest;
+import org.springframework.web.servlet.mvc.method.annotation.ResponseEntityExceptionHandler;
+
+/**
+ * Catches certain exceptions. This controller advice factors out try-catch
+ * blocks in many controller methods.
+ *
+ * Also see:<br>
+ * https://www.baeldung.com/exception-handling-for-rest-with-spring
+ * https://www.springboottutorial.com/spring-boot-exception-handling-for-rest-services
+ */
+@ControllerAdvice
+public class CustomResponseEntityExceptionHandler extends ResponseEntityExceptionHandler {
+
+    // Superclass has "logger" that is exposed here, so use a different name
+    private static final Logger log = LoggerFactory.getLogger(MethodHandles.lookup().lookupClass());
+
+    /**
+     * Logs the error and generates a JSON response when a REST controller method
+     * takes a RestClientResponseException. This is thrown by the Http client when a
+     * remote method returns a non-2xx code. All the controller methods are proxies
+     * in that they just forward the request along to a remote system, so if that
+     * remote system fails, return 502 plus some details about the failure, rather
+     * than the generic 500 that Spring-Boot will return on an uncaught exception.
+     *
+     * Why 502? I quote: <blockquote>HTTP server received an invalid response from a
+     * server it consulted when acting as a proxy or gateway.</blockquote>
+     *
+     * @param ex
+     *        The exception
+     *
+     * @param request
+     *        The original request
+     *
+     * @return A response entity with status code 502 plus some details in the body.
+     */
+    @ExceptionHandler({RestClientResponseException.class})
+    public final ResponseEntity<ErrorTransport> handleProxyMethodException(Exception ex, WebRequest request) {
+        // Capture the full stack trace in the log.
+        log.error("handleProxyMethodException: request {}, exception {}", request.getDescription(false),
+            ex.getMessage());
+        if (ex instanceof HttpStatusCodeException) {
+            HttpStatusCodeException hsce = (HttpStatusCodeException) ex;
+            return new ResponseEntity<>(new ErrorTransport(hsce.getRawStatusCode(), hsce.getResponseBodyAsString(),
+                ex.toString(), request.getDescription(false)), HttpStatus.BAD_GATEWAY);
+        } else {
+            return new ResponseEntity<>(new ErrorTransport(500, ex), HttpStatus.BAD_GATEWAY);
+        }
+    }
+
+}