beagled/RemoteIndexer.cs

   1 //
   2 // RemoteIndexer.cs
   3 //
   4 // Copyright (C) 2005 Novell, Inc.
   5 //
   6
   7 //
   8 // Permission is hereby granted, free of charge, to any person obtaining a
   9 // copy of this software and associated documentation files (the "Software"),
  10 // to deal in the Software without restriction, including without limitation
  11 // the rights to use, copy, modify, merge, publish, distribute, sublicense,
  12 // and/or sell copies of the Software, and to permit persons to whom the
  13 // Software is furnished to do so, subject to the following conditions:
  14 //
  15 // The above copyright notice and this permission notice shall be included in
  16 // all copies or substantial portions of the Software.
  17 //
  18 // THE SOFTWARE IS PROVIDED "AS IS", WITHOUT WARRANTY OF ANY KIND, EXPRESS OR
  19 // IMPLIED, INCLUDING BUT NOT LIMITED TO THE WARRANTIES OF MERCHANTABILITY,
  20 // FITNESS FOR A PARTICULAR PURPOSE AND NONINFRINGEMENT. IN NO EVENT SHALL THE
  21 // AUTHORS OR COPYRIGHT HOLDERS BE LIABLE FOR ANY CLAIM, DAMAGES OR OTHER
  22 // LIABILITY, WHETHER IN AN ACTION OF CONTRACT, TORT OR OTHERWISE, ARISING
  23 // FROM, OUT OF OR IN CONNECTION WITH THE SOFTWARE OR THE USE OR OTHER
  24 // DEALINGS IN THE SOFTWARE.
  25 //
  26
  27 using System;
  28 using System.Diagnostics;
  29 using System.IO;
  30 using System.Threading;
  31
  32 using Beagle;
  33 using Beagle.Util;
  34
  35 namespace Beagle.Daemon {
  36
  37         public class RemoteIndexer : IIndexer {
  38
  39                 static string helper_path;
  40
  41                 string remote_index_name;
  42                 int remote_index_minor_version = 0;
  43                 int last_item_count = -1;
  44
  45                 RemoteIndexerRequest pending_request = new RemoteIndexerRequest ();
  46                 object pending_request_lock = new object ();
  47
  48                 static RemoteIndexer ()
  49                 {
  50                         string bihp = Environment.GetEnvironmentVariable ("_BEAGLED_INDEX_HELPER_PATH");
  51                         if (bihp == null)
  52                                 throw new Exception ("_BEAGLED_INDEX_HELPER_PATH not set!");
  53
  54                         helper_path = Path.GetFullPath (Path.Combine (bihp, "beagled-index-helper"));
  55                         if (! File.Exists (helper_path))
  56                                 throw new Exception ("Could not find " + helper_path);
  57                         Logger.Log.Debug ("Found index helper at {0}", helper_path);
  58                 }
  59
  60                 static public IIndexer NewRemoteIndexer (string name, int minor_version)
  61                 {
  62                         return new RemoteIndexer (name, minor_version);
  63                 }
  64
  65                 public RemoteIndexer (string name, int minor_version)
  66                 {
  67                         this.remote_index_name = name;
  68                         this.remote_index_minor_version = minor_version;
  69                 }
  70
  71                 public void Add (Indexable indexable)
  72                 {
  73                         indexable.StoreStream ();
  74                         lock (pending_request_lock)
  75                                 pending_request.Add (indexable);
  76                 }
  77
  78                 public void Remove (Uri uri)
  79                 {
  80                         lock (pending_request_lock)
  81                                 pending_request.Remove (uri);
  82                 }
  83
  84                 public void Optimize ()
  85                 {
  86                         pending_request.OptimizeIndex = true;
  87                 }
  88
  89                 public IndexerReceipt [] FlushAndBlock ()
  90                 {
  91                         RemoteIndexerRequest flushed_request = null;
  92                         lock (pending_request) {
  93
  94                                 // If there isn't actually any work to do, just return
  95                                 // an empty array.
  96                                 if (pending_request.IsEmpty)
  97                                         return new IndexerReceipt [0];
  98
  99                                 flushed_request = pending_request;
 100                                 pending_request = new RemoteIndexerRequest ();
 101                         }
 102
 103                         RemoteIndexerResponse response;
 104                         response = SendRequest (flushed_request);
 105
 106                         if (response == null) {
 107                                 Logger.Log.Error ("Something terrible happened --- Flush failed");
 108                                 return null;
 109                         }
 110
 111                         last_item_count = response.ItemCount;
 112
 113                         if (response.Receipts != null && response.Receipts.Length > 0)
 114                                 return response.Receipts;
 115                         else
 116                                 return null;
 117                 }
 118
 119                 public event IIndexerFlushHandler FlushEvent;
 120
 121                 public void Flush ()
 122                 {
 123                         // FIXME: Right now we don't support a non-blocking flush,
 124                         // but it would be easy enough to do it in a thread.
 125
 126                         IndexerReceipt [] receipts;
 127
 128                         receipts = FlushAndBlock ();
 129
 130                         if (FlushEvent != null) {
 131                                 if (receipts != null)
 132                                         FlushEvent (this, receipts);
 133                                 FlushEvent (this, null); // all done
 134                         }
 135                 }
 136
 137                 public int GetItemCount ()
 138                 {
 139                         if (last_item_count == -1) {
 140                                 // Send an empty indexing request to cause the last item count to be
 141                                 // initialized.
 142                                 RemoteIndexerRequest request;
 143                                 request = new RemoteIndexerRequest ();
 144
 145                                 RemoteIndexerResponse response;
 146                                 response = SendRequest (request);
 147                                 if (response != null)
 148                                         last_item_count = response.ItemCount;
 149                                 else
 150                                         Logger.Log.Error ("Something terrible happened --- GetItemCount failed");
 151                         }
 152                         return last_item_count;
 153                 }
 154
 155                 /////////////////////////////////////////////////////////
 156
 157                 private RemoteIndexerResponse SendRequest (RemoteIndexerRequest request)
 158                 {
 159                         RemoteIndexerResponse response = null;
 160                         int exception_count = 0;
 161                         bool start_helper_by_hand = false;
 162
 163                         if (Environment.GetEnvironmentVariable ("BEAGLE_RUN_HELPER_BY_HAND") != null)
 164                                 start_helper_by_hand = true;
 165
 166                         request.RemoteIndexName = remote_index_name;
 167                         request.RemoteIndexMinorVersion = remote_index_minor_version;
 168
 169                         while (response == null
 170                                && exception_count < 5
 171                                 && ! Shutdown.ShutdownRequested) {
 172
 173                                 bool need_helper = false;
 174
 175                                 //Logger.Log.Debug ("Sending request!");
 176                                 try {
 177                                         response = request.Send () as RemoteIndexerResponse;
 178                                         Logger.Log.Debug ("Done sending request");
 179                                 } catch (ResponseMessageException ex) {
 180                                         Logger.Log.Debug ("Caught ResponseMessageException: {0}", ex.Message);
 181                                 } catch (System.Net.Sockets.SocketException ex) {
 182                                         Logger.Log.Debug ("Caught SocketException -- we probably need to launch a helper: {0}", ex.Message);
 183                                         need_helper = true;
 184                                 } catch (IOException ex) {
 185                                         Logger.Log.Debug ("Caught IOException --- we probably need to launch a helper: {0}", ex.Message);
 186                                         need_helper = true;
 187                                 }
 188
 189                                 // If we caught an exception...
 190                                 if (response == null) {
 191                                         if (! start_helper_by_hand || ! need_helper)
 192                                                 ++exception_count;
 193
 194                                         if (start_helper_by_hand) {
 195                                                 // Sleep briefly before trying again.
 196                                                 Thread.Sleep (1000);
 197                                         } else {
 198                                                 // Try to activate the helper.
 199                                                 LaunchHelper ();
 200                                         }
 201                                 }
 202                         }
 203
 204                         if (response == null && exception_count >= 5)
 205                                 Logger.Log.Error ("Exception limit exceeded trying to activate a helper.  Giving up on indexing!");
 206
 207                         return response;
 208                 }
 209
 210                 /////////////////////////////////////////////////////////
 211
 212                 static bool CheckHelper ()
 213                 {
 214                         string storage_dir = PathFinder.GetRemoteStorageDir (false);
 215
 216                         if (storage_dir == null)
 217                                 return false;
 218
 219                         // FIXME: We shouldn't need to know the path to the helper socket.
 220                         string socket_name = Path.Combine (storage_dir, "socket-helper");
 221
 222                         if (! File.Exists (socket_name))
 223                                 return false;
 224
 225                         // Open, and then immediately close, a connection to the helper's socket.
 226                         try {
 227                                 UnixClient test_client;
 228                                 test_client = new UnixClient (socket_name);
 229                                 test_client.Close ();
 230                                 return true;
 231                         } catch (Exception ex) {
 232                                 return false;
 233                         }
 234                 }
 235
 236                 static object helper_lock = new object ();
 237
 238                 static void LaunchHelper ()
 239                 {
 240                         // If we are in the process of shutting down, return immediately.
 241                         if (Shutdown.ShutdownRequested)
 242                                 return;
 243
 244                         lock (helper_lock) {
 245
 246                                 // If a helper appears to be running, return immediately.
 247                                 if (CheckHelper ())
 248                                         return;
 249
 250                                 Logger.Log.Debug ("Launching helper process");
 251
 252                                 Process p = new Process ();
 253                                 p.StartInfo.UseShellExecute = false;
 254                                 p.StartInfo.FileName = helper_path;
 255                                 p.Start ();
 256
 257                                 // Poll the helper's socket.  If the
 258                                 int poll_count = 0;
 259                                 bool found_helper;
 260                                 do {
 261                                         Thread.Sleep (200);
 262                                         ++poll_count;
 263                                         found_helper = CheckHelper ();
 264                                 } while (poll_count < 20
 265                                          && ! found_helper
 266                                          && ! Shutdown.ShutdownRequested);
 267
 268                                 if (! found_helper)
 269                                         throw new Exception ("Couldn't launch helper process");
 270                         }
 271                 }
 272         }
 273 }