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.beam.runners.dataflow.worker.status;
  
  import edu.umd.cs.findbugs.annotations.SuppressFBWarnings;
  import java.io.IOException;
  import java.io.PrintWriter;
  import java.util.LinkedHashMap;
  import javax.servlet.ServletException;
  import javax.servlet.http.HttpServletRequest;
  import javax.servlet.http.HttpServletResponse;
  import org.apache.beam.runners.dataflow.worker.status.DebugCapture.Capturable;
  
  /**
   * General servlet for providing a bunch of information on the statusz page.
   *
   * <p><b>Not actually serializable</b>. Its superclass is serializable but this subclass is not.
   */
  @SuppressFBWarnings("SE_BAD_FIELD") // not serializable
  public class StatuszServlet extends BaseStatusServlet implements Capturable {
  
    private static class DataProviderInfo {
      private final String longName;
      private final StatusDataProvider dataProvider;
  
      public DataProviderInfo(String longName, StatusDataProvider dataProvider) {
        this.longName = longName;
        this.dataProvider = dataProvider;
      }
    }
  
    private LinkedHashMap<String, DataProviderInfo> dataProviders = new LinkedHashMap<>();
  
    public StatuszServlet() {
      super("statusz");
    }
  
    public void addDataProvider(String shortName, String longName, StatusDataProvider provider) {
      dataProviders.put(shortName, new DataProviderInfo(longName, provider));
    }
  
    @Override
    protected void doGet(HttpServletRequest request, HttpServletResponse response)
        throws IOException, ServletException {
      response.setStatus(HttpServletResponse.SC_OK);
      PrintWriter writer = response.getWriter();
      captureData(writer);
    }
  
    @Override
    public String pageName() {
      return "/statusz";
    }
  
    @Override
    public void captureData(PrintWriter writer) {
      writer.println("<html>");
  
      writer.println("<h1>Worker Harness</h1>");
  
      for (DataProviderInfo info : dataProviders.values()) {
        writer.print("<h2>");
        writer.print(info.longName);
        writer.println("</h2>");
  
        info.dataProvider.appendSummaryHtml(writer);
      }
      writer.println("</html>");
    }
  }
  