feat(web): Adding request logging interceptor (#378)

gate-web/src/main/groovy/com/netflix/spinnaker/gate/config/GateWebConfig.groovy

@@ -17,6 +17,7 @@
 package com.netflix.spinnaker.gate.config
 
 import com.netflix.spectator.api.Registry
+import com.netflix.spinnaker.gate.interceptors.RequestLoggingInterceptor
 import com.netflix.spinnaker.gate.ratelimit.RateLimiter
 import com.netflix.spinnaker.gate.ratelimit.RateLimitingInterceptor
 import com.netflix.spinnaker.gate.retrofit.UpstreamBadRequest
@@ -56,6 +57,9 @@ public class GateWebConfig extends WebMvcConfigurerAdapter {
   @Value('${rateLimit.learning:true}')
   Boolean rateLimitLearningMode
 
+  @Value('${requestLogging.enabled:false}')
+  Boolean requestLogging
+
   @Override
   public void addInterceptors(InterceptorRegistry registry) {
     registry.addInterceptor(
@@ -64,6 +68,10 @@ public class GateWebConfig extends WebMvcConfigurerAdapter {
       )
     )
 
+    if (requestLogging) {
+      registry.addInterceptor(new RequestLoggingInterceptor());
+    }
+
     if (rateLimiter != null) {
       registry.addInterceptor(new RateLimitingInterceptor(rateLimiter, spectatorRegistry, rateLimiterConfiguration))
     }

gate-web/src/main/groovy/com/netflix/spinnaker/gate/interceptors/RequestLoggingInterceptor.java

@@ -0,0 +1,67 @@
+/*
+ * Copyright 2017 Netflix, Inc.
+ *
+ * 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.
+ */
+package com.netflix.spinnaker.gate.interceptors;
+
+import org.slf4j.Logger;
+import org.slf4j.LoggerFactory;
+import org.springframework.web.servlet.handler.HandlerInterceptorAdapter;
+import org.springframework.web.util.ContentCachingResponseWrapper;
+
+import javax.servlet.http.HttpServletRequest;
+import javax.servlet.http.HttpServletResponse;
+
+public class RequestLoggingInterceptor extends HandlerInterceptorAdapter {
+
+  private Logger log = LoggerFactory.getLogger(getClass());
+
+  @Override
+  public void afterCompletion(HttpServletRequest request, HttpServletResponse response, Object handler, Exception ex) throws Exception {
+    // 127.0.0.1 "GET /limecat.jpg HTTP/1.0" 200 2326
+    log.debug(String.format(
+      "%s \"%s %s %s\" %d %d",
+      sourceIpAddress(request),
+      request.getMethod(),
+      getRequestEndpoint(request),
+      request.getProtocol(),
+      response.getStatus(),
+      getResponseSize(response)
+    ));
+  }
+
+  private static String sourceIpAddress(HttpServletRequest request) {
+    String ip = request.getHeader("X-FORWARDED-FOR");
+    if (ip == null) {
+      return request.getRemoteAddr();
+    }
+    return ip;
+  }
+
+  private static String getRequestEndpoint(HttpServletRequest request) {
+    String endpoint = request.getRequestURI();
+    if (request.getQueryString() != null) {
+      return endpoint + "?" + request.getQueryString();
+    }
+    return endpoint;
+  }
+
+  private static int getResponseSize(HttpServletResponse response) {
+    if (response instanceof ContentCachingResponseWrapper) {
+      return ((ContentCachingResponseWrapper) response).getContentAsByteArray().length;
+    }
+    return -1;
+  }
+
+}