client/src/main/java/org/onap/aaf/cadi/locator/HotPeerLocator.java

   1 /*******************************************************************************\r
   2  * ============LICENSE_START====================================================\r
   3  * * org.onap.aaf\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 package org.onap.aaf.cadi.locator;\r
  24 \r
  25 import org.onap.aaf.cadi.Access;\r
  26 import org.onap.aaf.cadi.Locator;\r
  27 import org.onap.aaf.cadi.LocatorException;\r
  28 import org.onap.aaf.cadi.Access.Level;\r
  29 import org.onap.aaf.cadi.routing.GreatCircle;\r
  30 \r
  31 import org.onap.aaf.inno.env.util.Split;\r
  32 \r
  33 /**\r
  34  * This Locator is to handle Hot Peer load protection, when the Servers are \r
  35  *      1) Static\r
  36  *      2) Well known client URL\r
  37  * \r
  38  * The intention is to change traffic over to the Hot Peer, if a server goes down, and reinstate\r
  39  * when it is back up.\r
  40  * \r
  41  * Example of this kind of Service is a MS Certificate Server\r
  42  * \r
  43  *\r
  44  *\r
  45  * @param <CLIENT>\r
  46  */\r
  47 public abstract class HotPeerLocator<CLIENT> implements Locator<CLIENT> {\r
  48                 private final String[] urlstrs;\r
  49                 private final CLIENT[] clients;\r
  50                 private final long[] failures;\r
  51                 private final double[] distances;\r
  52                 private int preferred;\r
  53                 private long invalidateTime;\r
  54                 private Thread refreshThread;\r
  55                 protected Access access;\r
  56 \r
  57                 /**\r
  58                  * Construct:  Expect one or more Strings in the form:\r
  59                  *              192.555.112.223:39/38.88087/-77.30122\r
  60                  *    separated by commas\r
  61                  * \r
  62                  * @param trans\r
  63                  * @param urlstr\r
  64                  * @param invalidateTime\r
  65                  * @param localLatitude\r
  66                  * @param localLongitude\r
  67                  * @throws LocatorException\r
  68                  */\r
  69                 @SuppressWarnings("unchecked")\r
  70                 protected HotPeerLocator(Access access, final String urlstr, final long invalidateTime, final String localLatitude, final String localLongitude) throws LocatorException {\r
  71                         this.access = access;\r
  72                         urlstrs = Split.split(',', urlstr);\r
  73                         clients = (CLIENT[])new Object[urlstrs.length];\r
  74                         failures = new long[urlstrs.length];\r
  75                         distances= new double[urlstrs.length];\r
  76                         this.invalidateTime = invalidateTime;\r
  77                         \r
  78                         double distance = Double.MAX_VALUE;\r
  79                         for(int i=0;i<urlstrs.length;++i) {\r
  80                                 String[] info = Split.split('/', urlstrs[i]);\r
  81                                 if(info.length<3) {\r
  82                                         throw new LocatorException("Configuration needs LAT and LONG, i.e. ip:port/lat/long");\r
  83                                 }\r
  84                                 try {\r
  85                                         clients[i] = _newClient(urlstrs[i]);\r
  86                                         failures[i] = 0L;\r
  87                                 } catch(LocatorException le) {\r
  88                                         failures[i] = System.currentTimeMillis()+invalidateTime;\r
  89                                 }\r
  90                                 \r
  91                                 double d = GreatCircle.calc(info[1],info[2],localLatitude,localLongitude);\r
  92                                 distances[i]=d;\r
  93                                 \r
  94                                 // find preferred server\r
  95                                 if(d<distance) {\r
  96                                         preferred = i;\r
  97                                         distance=d;\r
  98                                 }\r
  99                         }\r
 100                         \r
 101                         access.printf(Level.INIT,"Preferred Client is %s",urlstrs[preferred]);\r
 102                         for(int i=0;i<urlstrs.length;++i) {\r
 103                                 if(i!=preferred) {\r
 104                                         access.printf(Level.INIT,"Alternate Client is %s",urlstrs[i]);\r
 105                                 }\r
 106                         }\r
 107                 }\r
 108                 \r
 109                 protected abstract CLIENT _newClient(String hostInfo) throws LocatorException;\r
 110                 /**\r
 111                  * If client can reconnect, then return.  Otherwise, destroy and return null;\r
 112                  * @param client\r
 113                  * @return\r
 114                  * @throws LocatorException\r
 115                  */\r
 116                 protected abstract CLIENT _invalidate(CLIENT client);\r
 117                 \r
 118                 protected abstract void _destroy(CLIENT client);\r
 119                 \r
 120                 @Override\r
 121                 public Item best() throws LocatorException {\r
 122                         if(failures[preferred]==0L) {\r
 123                                 return new HPItem(preferred);\r
 124                         } else {\r
 125                                 long now = System.currentTimeMillis();\r
 126                                 double d = Double.MAX_VALUE;\r
 127                                 int best = -1;\r
 128                                 boolean tickle = false;\r
 129                                 // try for best existing client\r
 130                                 for(int i=0;i<urlstrs.length;++i) {\r
 131                                         if(failures[i]<now && distances[i]<d) {\r
 132                                                 if(clients[i]!=null) {\r
 133                                                         best = i;\r
 134                                                         break;\r
 135                                                 } else {\r
 136                                                         tickle = true; // There's some failed clients which can be restored\r
 137                                                 }\r
 138                                         }\r
 139                                 }\r
 140                                 if(best<0 && tickle) {\r
 141                                         tickle=false;\r
 142                                         if(refresh()) {\r
 143                                                 // try again\r
 144                                                 for(int i=0;i<urlstrs.length;++i) {\r
 145                                                         if(failures[i]==0L && distances[i]<d) {\r
 146                                                                 if(clients[i]!=null) {\r
 147                                                                         best = i;\r
 148                                                                         break;\r
 149                                                                 }\r
 150                                                         }\r
 151                                                 }\r
 152                                         }\r
 153                                 }\r
 154                         \r
 155                                 /*\r
 156                                  * If a valid client is available, but there are some that can refresh, return the client immediately\r
 157                                  * but start a Thread to do the background Client setup.\r
 158                                  */\r
 159                                 if(tickle) {\r
 160                                         synchronized(clients) {\r
 161                                                 if(refreshThread==null) {\r
 162                                                         refreshThread = new Thread(new Runnable(){\r
 163                                                                 @Override\r
 164                                                                 public void run() {\r
 165                                                                         refresh();\r
 166                                                                         refreshThread = null;\r
 167                                                                 }\r
 168                                                         });\r
 169                                                         refreshThread.setDaemon(true);\r
 170                                                         refreshThread.start();\r
 171                                                 }\r
 172                                         }\r
 173                                 }\r
 174                                 \r
 175                                 if(best<0) {\r
 176                                         throw new LocatorException("No Clients available");\r
 177                                 }\r
 178 \r
 179                                 \r
 180                                 return new HPItem(best);\r
 181                         }\r
 182                 }\r
 183                 \r
 184 \r
 185                 @Override\r
 186                 public CLIENT get(Item item) throws LocatorException {\r
 187                         HPItem hpi = (HPItem)item;\r
 188                         CLIENT c = clients[hpi.idx];\r
 189                         if(c==null) {\r
 190                                 if(failures[hpi.idx]>System.currentTimeMillis()) {\r
 191                                         throw new LocatorException("Client requested is invalid");      \r
 192                                 } else {\r
 193                                         synchronized(clients) {\r
 194                                                 c = _newClient(urlstrs[hpi.idx]);\r
 195                                                 failures[hpi.idx]=0L;\r
 196                                         }\r
 197                                 }\r
 198                         } else if(failures[hpi.idx]>0){\r
 199                                 throw new LocatorException("Client requested is invalid");\r
 200                         }\r
 201                         return c;\r
 202                 }\r
 203                 \r
 204                 public String info(Item item) {\r
 205                         HPItem hpi = (HPItem)item;\r
 206                         if(hpi!=null && hpi.idx<urlstrs.length) {\r
 207                                 return urlstrs[hpi.idx];\r
 208                         } else {\r
 209                                 return "Invalid Item";\r
 210                         }\r
 211                 }\r
 212 \r
 213                 @Override\r
 214                 public boolean hasItems() {\r
 215                         for(int i=0;i<clients.length;++i) {\r
 216                                 if(clients[i]!=null && failures[i]==0L) {\r
 217                                         return true;\r
 218                                 }\r
 219                         }\r
 220                         return false;\r
 221                 }\r
 222                 \r
 223                 @Override\r
 224                 public synchronized void invalidate(Item item) throws LocatorException {\r
 225                         HPItem hpi = (HPItem)item;\r
 226                         failures[hpi.idx] = System.currentTimeMillis() + invalidateTime;\r
 227                         CLIENT c = clients[hpi.idx];\r
 228                         clients[hpi.idx] = _invalidate(c);\r
 229                 }\r
 230                 \r
 231                 @Override\r
 232                 public Item first() throws LocatorException {\r
 233                         return new HPItem(0);\r
 234                 }\r
 235                 \r
 236                 @Override\r
 237                 public Item next(Item item) throws LocatorException {\r
 238                         HPItem hpi = (HPItem)item;\r
 239                         if(++hpi.idx>=clients.length) {\r
 240                                 return null;\r
 241                         }\r
 242                         return hpi;\r
 243                 }\r
 244                 \r
 245                 @Override\r
 246                 public boolean refresh() {\r
 247                         boolean force = !hasItems(); // If no Items at all, reset\r
 248                         boolean rv = true;\r
 249                         long now = System.currentTimeMillis();\r
 250                         for(int i=0;i<clients.length;++i) {\r
 251                                 if(failures[i]>0L && (failures[i]<now || force)) { // retry\r
 252                                         try {\r
 253                                                 synchronized(clients) {\r
 254                                                         if(clients[i]==null) {\r
 255                                                                 clients[i]=_newClient(urlstrs[i]);\r
 256                                                         }\r
 257                                                         failures[i]=0L;\r
 258                                                 }\r
 259                                         } catch (LocatorException e) {\r
 260                                                 failures[i]=now+invalidateTime;\r
 261                                                 rv = false;\r
 262                                         }\r
 263                                 }\r
 264                         }\r
 265                         return rv;\r
 266                 }\r
 267                 \r
 268                 @Override\r
 269                 public void destroy() {\r
 270                         for(int i=0;i<clients.length;++i) {\r
 271                                 if(clients[i]!=null) {\r
 272                                         _destroy(clients[i]);\r
 273                                         clients[i] = null;\r
 274                                 }\r
 275                         }\r
 276                 }\r
 277 \r
 278                 private static class HPItem implements Item {\r
 279                         private int idx;\r
 280 \r
 281                         public HPItem(int i) {\r
 282                                 idx = i;\r
 283                         }\r
 284                 }\r
 285                 \r
 286 \r
 287                 /*\r
 288                  * Convenience Functions\r
 289                  */\r
 290                 public CLIENT bestClient() throws LocatorException {\r
 291                         return get(best());\r
 292                 }\r
 293 \r
 294                 public boolean invalidate(CLIENT client) throws LocatorException {\r
 295                         for(int i=0;i<clients.length;++i) {\r
 296                                 if(clients[i]==client) { // yes, "==" is appropriate here.. Comparing Java Object Reference\r
 297                                         invalidate(new HPItem(i));\r
 298                                         return true;\r
 299                                 }\r
 300                         }\r
 301                         return false;\r
 302                 }\r
 303 \r
 304         }\r