datarouter-prov/src/main/java/com/att/research/datarouter/provisioning/utils/ThrottleFilter.java

   1 /*******************************************************************************\r
   2  * ============LICENSE_START==================================================\r
   3  * * org.onap.dmaap\r
   4  * * ===========================================================================\r
   5  * * Copyright © 2017 AT&T Intellectual Property. All rights reserved.\r
   6  * * ===========================================================================\r
   7  * * Licensed under the Apache License, Version 2.0 (the "License");\r
   8  * * you may not use this file except in compliance with the License.\r
   9  * * You may obtain a copy of the License at\r
  10  * * \r
  11  *  *      http://www.apache.org/licenses/LICENSE-2.0\r
  12  * * \r
  13  *  * Unless required by applicable law or agreed to in writing, software\r
  14  * * distributed under the License is distributed on an "AS IS" BASIS,\r
  15  * * WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.\r
  16  * * See the License for the specific language governing permissions and\r
  17  * * limitations under the License.\r
  18  * * ============LICENSE_END====================================================\r
  19  * *\r
  20  * * ECOMP is a trademark and service mark of AT&T Intellectual Property.\r
  21  * *\r
  22  ******************************************************************************/\r
  23 \r
  24 \r
  25 package com.att.research.datarouter.provisioning.utils;\r
  26 \r
  27 import java.io.IOException;\r
  28 import java.io.InputStream;\r
  29 import java.util.ArrayList;\r
  30 import java.util.HashMap;\r
  31 import java.util.List;\r
  32 import java.util.Map;\r
  33 import java.util.Timer;\r
  34 import java.util.TimerTask;\r
  35 import java.util.Vector;\r
  36 \r
  37 import javax.servlet.Filter;\r
  38 import javax.servlet.FilterChain;\r
  39 import javax.servlet.FilterConfig;\r
  40 import javax.servlet.ServletException;\r
  41 import javax.servlet.ServletRequest;\r
  42 import javax.servlet.ServletResponse;\r
  43 import javax.servlet.http.HttpServletRequest;\r
  44 import javax.servlet.http.HttpServletResponse;\r
  45 \r
  46 import com.att.research.datarouter.provisioning.beans.Parameters;\r
  47 \r
  48 import org.apache.log4j.Logger;\r
  49 import org.eclipse.jetty.continuation.Continuation;\r
  50 import org.eclipse.jetty.continuation.ContinuationSupport;\r
  51 import org.eclipse.jetty.server.AbstractHttpConnection;\r
  52 import org.eclipse.jetty.server.Request;\r
  53 \r
  54 /**\r
  55  * This filter checks /publish requests to the provisioning server to allow ill-behaved publishers to be throttled.\r
  56  * It is configured via the provisioning parameter THROTTLE_FILTER.\r
  57  * The THROTTLE_FILTER provisioning parameter can have these values:\r
  58  * <table>\r
  59  * <tr><td>(no value)</td><td>filter disabled</td></tr>\r
  60  * <tr><td>off</td><td>filter disabled</td></tr>\r
  61  * <tr><td>N[,M[,action]]</td><td>set N, M, and action (used in the algorithm below).\r
  62  *     Action is <i>drop</i> or <i>throttle</i>.\r
  63  *     If M is missing, it defaults to 5 minutes.\r
  64  *     If the action is missing, it defaults to <i>drop</i>.\r
  65  * </td></tr>\r
  66  * </table>\r
  67  * <p>\r
  68  * The <i>action</i> is triggered iff:\r
  69  * <ol>\r
  70  * <li>the filter is enabled, and</li>\r
  71  * <li>N /publish requests come to the provisioning server in M minutes\r
  72  *   <ol>\r
  73  *   <li>from the same IP address</li>\r
  74  *   <li>for the same feed</li>\r
  75  *   <li>lacking the <i>Expect: 100-continue</i> header</li>\r
  76  *   </ol>\r
  77  * </li>\r
  78  * </ol>\r
  79  * The action that can be performed (if triggered) are:\r
  80  * <ol>\r
  81  * <li><i>drop</i> - the connection is dropped immediately.</li>\r
  82  * <li><i>throttle</i> - [not supported] the connection is put into a low priority queue with all other throttled connections.\r
  83  *   These are then processed at a slower rate.  Note: this option does not work correctly, and is disabled.\r
  84  *   The only action that is supported is <i>drop</i>.\r
  85  * </li>\r
  86  * </ol>\r
  87  *\r
  88  * @author Robert Eby\r
  89  * @version $Id: ThrottleFilter.java,v 1.2 2014/03/12 19:45:41 eby Exp $\r
  90  */\r
  91 public class ThrottleFilter extends TimerTask implements Filter {\r
  92         public  static final int    DEFAULT_N       = 10;\r
  93         public  static final int    DEFAULT_M       = 5;\r
  94         public  static final String THROTTLE_MARKER = "com.att.research.datarouter.provisioning.THROTTLE_MARKER";\r
  95         private static final String JETTY_REQUEST   = "org.eclipse.jetty.server.Request";\r
  96         private static final long   ONE_MINUTE      = 60000L;\r
  97         private static final int    ACTION_DROP     = 0;\r
  98         private static final int    ACTION_THROTTLE = 1;\r
  99 \r
 100         // Configuration\r
 101         private static boolean enabled = false;         // enabled or not\r
 102         private static int n_requests = 0;                      // number of requests in M minutes\r
 103         private static int m_minutes = 0;                       // sampling period\r
 104         private static int action = ACTION_DROP;        // action to take (throttle or drop)\r
 105 \r
 106         private static Logger logger = Logger.getLogger("com.att.research.datarouter.provisioning.internal");\r
 107         private static Map<String, Counter> map = new HashMap<String, Counter>();\r
 108         private static final Timer rolex = new Timer();\r
 109 \r
 110         @Override\r
 111         public void init(FilterConfig arg0) throws ServletException {\r
 112                 configure();\r
 113                 rolex.scheduleAtFixedRate(this, 5*60000L, 5*60000L);    // Run once every 5 minutes to clean map\r
 114         }\r
 115 \r
 116         /**\r
 117          * Configure the throttle.  This should be called from BaseServlet.provisioningParametersChanged(), to make sure it stays up to date.\r
 118          */\r
 119         public static void configure() {\r
 120                 Parameters p = Parameters.getParameter(Parameters.THROTTLE_FILTER);\r
 121                 if (p != null) {\r
 122                         try {\r
 123                                 Class.forName(JETTY_REQUEST);\r
 124                                 String v = p.getValue();\r
 125                                 if (v != null && !v.equals("off")) {\r
 126                                         String[] pp = v.split(",");\r
 127                                         if (pp != null) {\r
 128                                                 n_requests = (pp.length > 0) ? getInt(pp[0], DEFAULT_N) : DEFAULT_N;\r
 129                                                 m_minutes  = (pp.length > 1) ? getInt(pp[1], DEFAULT_M) : DEFAULT_M;\r
 130                                                 action     = (pp.length > 2 && pp[2] != null && pp[2].equalsIgnoreCase("throttle")) ? ACTION_THROTTLE : ACTION_DROP;\r
 131                                                 enabled    = true;\r
 132                                                 // ACTION_THROTTLE is not currently working, so is not supported\r
 133                                                 if (action == ACTION_THROTTLE) {\r
 134                                                         action = ACTION_DROP;\r
 135                                                         logger.info("Throttling is not currently supported; action changed to DROP");\r
 136                                                 }\r
 137                                                 logger.info("ThrottleFilter is ENABLED for /publish requests; N="+n_requests+", M="+m_minutes+", Action="+action);\r
 138                                                 return;\r
 139                                         }\r
 140                                 }\r
 141                         } catch (ClassNotFoundException e) {\r
 142                                 logger.warn("Class "+JETTY_REQUEST+" is not available; this filter requires Jetty.");\r
 143                         }\r
 144                 }\r
 145                 logger.info("ThrottleFilter is DISABLED for /publish requests.");\r
 146                 enabled = false;\r
 147                 map.clear();\r
 148         }\r
 149         private static int getInt(String s, int deflt) {\r
 150                 try {\r
 151                         return Integer.parseInt(s);\r
 152                 } catch (NumberFormatException x) {\r
 153                         return deflt;\r
 154                 }\r
 155         }\r
 156         @Override\r
 157         public void destroy() {\r
 158                 rolex.cancel();\r
 159                 map.clear();\r
 160         }\r
 161 \r
 162         @Override\r
 163         public void doFilter(ServletRequest request, ServletResponse response, FilterChain chain)\r
 164                 throws IOException, ServletException\r
 165         {\r
 166                 if (enabled && action == ACTION_THROTTLE) {\r
 167                         throttleFilter((HttpServletRequest) request, (HttpServletResponse) response, chain);\r
 168                 } else if (enabled) {\r
 169                         dropFilter((HttpServletRequest) request, (HttpServletResponse) response, chain);\r
 170                 } else {\r
 171                         chain.doFilter(request, response);\r
 172                 }\r
 173         }\r
 174         public void dropFilter(HttpServletRequest request, HttpServletResponse response, FilterChain chain)\r
 175                 throws IOException, ServletException\r
 176         {\r
 177                 int rate = getRequestRate((HttpServletRequest) request);\r
 178                 if (rate >= n_requests) {\r
 179                         // drop request - only works under Jetty\r
 180                         String m = String.format("Dropping connection: %s %d bad connections in %d minutes", getConnectionId((HttpServletRequest) request), rate, m_minutes);\r
 181                         logger.info(m);\r
 182                         Request base_request = (request instanceof Request)\r
 183                                 ? (Request) request\r
 184                                 : AbstractHttpConnection.getCurrentConnection().getRequest();\r
 185                         base_request.getConnection().getEndPoint().close();\r
 186                 } else {\r
 187                         chain.doFilter(request, response);\r
 188                 }\r
 189         }\r
 190         public void throttleFilter(HttpServletRequest request, HttpServletResponse response, FilterChain chain)\r
 191                 throws IOException, ServletException\r
 192         {\r
 193                 // throttle request\r
 194                 String id = getConnectionId((HttpServletRequest) request);\r
 195                 int rate = getRequestRate((HttpServletRequest) request);\r
 196                 Object results = request.getAttribute(THROTTLE_MARKER);\r
 197                 if (rate >= n_requests && results == null) {\r
 198                         String m = String.format("Throttling connection: %s %d bad connections in %d minutes", getConnectionId((HttpServletRequest) request), rate, m_minutes);\r
 199                         logger.info(m);\r
 200                         Continuation continuation = ContinuationSupport.getContinuation(request);\r
 201                         continuation.suspend();\r
 202                         register(id, continuation);\r
 203                         continuation.undispatch();\r
 204                 } else {\r
 205                         chain.doFilter(request, response);\r
 206                         @SuppressWarnings("resource")\r
 207                         InputStream is = request.getInputStream();\r
 208                         byte[] b = new byte[4096];\r
 209                         int n = is.read(b);\r
 210                         while (n > 0) {\r
 211                                 n = is.read(b);\r
 212                         }\r
 213                         resume(id);\r
 214                 }\r
 215         }\r
 216         private Map<String, List<Continuation>> suspended_requests = new HashMap<String, List<Continuation>>();\r
 217         private void register(String id, Continuation continuation) {\r
 218                 synchronized (suspended_requests) {\r
 219                         List<Continuation> list = suspended_requests.get(id);\r
 220                         if (list == null) {\r
 221                                 list = new ArrayList<Continuation>();\r
 222                                 suspended_requests.put(id,  list);\r
 223                         }\r
 224                         list.add(continuation);\r
 225                 }\r
 226         }\r
 227         private void resume(String id) {\r
 228                 synchronized (suspended_requests) {\r
 229                         List<Continuation> list = suspended_requests.get(id);\r
 230                         if (list != null) {\r
 231                                 // when the waited for event happens\r
 232                                 Continuation continuation = list.remove(0);\r
 233                                 continuation.setAttribute(ThrottleFilter.THROTTLE_MARKER, new Object());\r
 234                                 continuation.resume();\r
 235                         }\r
 236                 }\r
 237         }\r
 238 \r
 239         /**\r
 240          * Return a count of number of requests in the last M minutes, iff this is a "bad" request.\r
 241          * If the request has been resumed (if it contains the THROTTLE_MARKER) it is considered good.\r
 242          * @param request the request\r
 243          * @return number of requests in the last M minutes, 0 means it is a "good" request\r
 244          */\r
 245         private int getRequestRate(HttpServletRequest request) {\r
 246                 String expecthdr = request.getHeader("Expect");\r
 247                 if (expecthdr != null && expecthdr.equalsIgnoreCase("100-continue"))\r
 248                         return 0;\r
 249 \r
 250                 String key = getConnectionId(request);\r
 251                 synchronized (map) {\r
 252                         Counter cnt = map.get(key);\r
 253                         if (cnt == null) {\r
 254                                 cnt = new Counter();\r
 255                                 map.put(key, cnt);\r
 256                         }\r
 257                         int n = cnt.getRequestRate();\r
 258                         return n;\r
 259                 }\r
 260         }\r
 261 \r
 262         public class Counter {\r
 263                 private List<Long> times = new Vector<Long>();  // a record of request times\r
 264                 public int prune() {\r
 265                         try {\r
 266                                 long n = System.currentTimeMillis() - (m_minutes * ONE_MINUTE);\r
 267                                 long t = times.get(0);\r
 268                                 while (t < n) {\r
 269                                         times.remove(0);\r
 270                                         t = times.get(0);\r
 271                                 }\r
 272                         } catch (IndexOutOfBoundsException e) {\r
 273                                 // ignore\r
 274                         }\r
 275                         return times.size();\r
 276                 }\r
 277                 public int getRequestRate() {\r
 278                         times.add(System.currentTimeMillis());\r
 279                         return prune();\r
 280                 }\r
 281         }\r
 282 \r
 283         /**\r
 284          *  Identify a connection by endpoint IP address, and feed ID.\r
 285          */\r
 286         private String getConnectionId(HttpServletRequest req) {\r
 287                 return req.getRemoteAddr() + "/" + getFeedId(req);\r
 288         }\r
 289         private int getFeedId(HttpServletRequest req) {\r
 290                 String path = req.getPathInfo();\r
 291                 if (path == null || path.length() < 2)\r
 292                         return -1;\r
 293                 path = path.substring(1);\r
 294                 int ix = path.indexOf('/');\r
 295                 if (ix < 0 || ix == path.length()-1)\r
 296                         return -2;\r
 297                 try {\r
 298                         int feedid = Integer.parseInt(path.substring(0, ix));\r
 299                         return feedid;\r
 300                 } catch (NumberFormatException e) {\r
 301                         return -1;\r
 302                 }\r
 303         }\r
 304 \r
 305         @Override\r
 306         public void run() {\r
 307                 // Once every 5 minutes, go through the map, and remove empty entrys\r
 308                 for (Object s : map.keySet().toArray()) {\r
 309                         synchronized (map) {\r
 310                                 Counter c = map.get(s);\r
 311                                 if (c.prune() <= 0)\r
 312                                         map.remove(s);\r
 313                         }\r
 314                 }\r
 315         }\r
 316 }\r