content: /*
   * Licensed to the Apache Software Foundation (ASF) under one
   * or more contributor license agreements.  See the NOTICE file
   * distributed with this work for additional information
   * regarding copyright ownership.  The ASF licenses this file
   * to you 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 org.apache.ambari.server.view;
  
  import java.io.IOException;
  import java.util.regex.Matcher;
  import java.util.regex.Pattern;
  
  import jakarta.servlet.Filter;
  import jakarta.servlet.FilterChain;
  import jakarta.servlet.FilterConfig;
  import jakarta.servlet.ServletException;
  import jakarta.servlet.ServletRequest;
  import jakarta.servlet.ServletResponse;
  import jakarta.servlet.http.HttpServletRequest;
  
  import org.slf4j.MDC;
  
  import com.google.inject.Singleton;
  
  /**
   * Inserts view name, view version and view instance name into MDC info for views REST for logging in views.
   */
  @Singleton
  public class AmbariViewsMDCLoggingFilter implements Filter {
  
    private final static String patternStr = "/api/v1/views/(.*)/versions/(.*)/instances/([^/]+).*";
    private final static Pattern pattern = Pattern.compile(patternStr);
  
    @Override
    public void init(FilterConfig filterConfig) throws ServletException {
      // do nothing
    }
  
    @Override
    public void doFilter(ServletRequest servletRequest, ServletResponse servletResponse, FilterChain filterChain) throws IOException, ServletException {
  
      buildMDC(servletRequest);
      try {
        filterChain.doFilter(servletRequest, servletResponse);
      } finally {
        clear();
      }
    }
  
    private void buildMDC(ServletRequest request) {
      if ((request instanceof HttpServletRequest) && MDC.getMDCAdapter() != null) {
        String url = ((HttpServletRequest) request).getRequestURI();
        Matcher matcher = pattern.matcher(url);
        if (matcher.find()) {
          MDC.put("viewName", matcher.group(1));
          MDC.put("viewVersion", matcher.group(2));
          MDC.put("viewInstanceName", matcher.group(3));
        }
      }
    }
  
    private void clear() {
      MDC.clear();
    }
  
    @Override
    public void destroy() {
      //do nothing
    }
  }
  