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 using Mono.Unix;
  32
  33 using Beagle;
  34 using Beagle.Util;
  35
  36 namespace Beagle.Daemon {
  37
  38         public class RemoteIndexer : IIndexer {
  39
  40                 static string helper_path;
  41                 static int helper_pid = -1;
  42
  43                 string remote_index_name;
  44                 int remote_index_minor_version = 0;
  45                 int last_item_count = -1;
  46
  47                 static RemoteIndexer ()
  48                 {
  49                         string bihp = Environment.GetEnvironmentVariable ("_BEAGLED_INDEX_HELPER_PATH");
  50                         if (bihp == null)
  51                                 throw new Exception ("_BEAGLED_INDEX_HELPER_PATH not set!");
  52
  53                         helper_path = Path.GetFullPath (Path.Combine (bihp, "beagled-index-helper"));
  54                         if (! File.Exists (helper_path))
  55                                 throw new Exception ("Could not find " + helper_path);
  56                         Logger.Log.Debug ("Found index helper at {0}", helper_path);
  57                 }
  58
  59                 static public IIndexer NewRemoteIndexer (string name, int minor_version)
  60                 {
  61                         return new RemoteIndexer (name, minor_version);
  62                 }
  63
  64                 public RemoteIndexer (string name, int minor_version)
  65                 {
  66                         this.remote_index_name = name;
  67                         this.remote_index_minor_version = minor_version;
  68                 }
  69
  70                 public IndexerReceipt [] Flush (IndexerRequest request)
  71                 {
  72                         // If there isn't actually any work to do, just return
  73                         // an empty array.
  74                         if (request.IsEmpty)
  75                                 return new IndexerReceipt [0];
  76
  77                         // Iterate through the items in the IndexerRequest to
  78                         // store the streams before passing them to the helper.
  79                         foreach (Indexable indexable in request.Indexables) {
  80                                 if (indexable.Type == IndexableType.Add)
  81                                         indexable.StoreStream ();
  82                         }
  83
  84                         RemoteIndexerRequest remote_request;
  85                         remote_request = new RemoteIndexerRequest ();
  86                         remote_request.RemoteIndexName = this.remote_index_name;
  87                         remote_request.RemoteIndexMinorVersion = this.remote_index_minor_version;
  88                         remote_request.Request = request;
  89
  90                         RemoteIndexerResponse response;
  91                         response = SendRequest (remote_request);
  92
  93                         if (response == null) {
  94                                 Logger.Log.Error ("Something terrible happened --- Flush failed");
  95                                 request.Cleanup ();
  96                                 return null;
  97                         }
  98
  99                         last_item_count = response.ItemCount;
 100
 101                         return response.Receipts;
 102                 }
 103
 104                 public int GetItemCount ()
 105                 {
 106                         if (last_item_count == -1) {
 107                                 // Send an empty indexing request to cause the last item count to be
 108                                 // initialized.
 109                                 RemoteIndexerRequest request;
 110                                 request = new RemoteIndexerRequest ();
 111
 112                                 RemoteIndexerResponse response;
 113                                 response = SendRequest (request);
 114                                 if (response != null)
 115                                         last_item_count = response.ItemCount;
 116                                 else
 117                                         Logger.Log.Error ("Something terrible happened --- GetItemCount failed");
 118                         }
 119
 120                         return last_item_count;
 121                 }
 122
 123                 /////////////////////////////////////////////////////////
 124
 125                 private RemoteIndexerResponse SendRequest (RemoteIndexerRequest request)
 126                 {
 127                         RemoteIndexerResponse response = null;
 128                         int exception_count = 0;
 129                         bool start_helper_by_hand = false;
 130
 131                         if (Environment.GetEnvironmentVariable ("BEAGLE_RUN_HELPER_BY_HAND") != null)
 132                                 start_helper_by_hand = true;
 133
 134                         request.RemoteIndexName = remote_index_name;
 135                         request.RemoteIndexMinorVersion = remote_index_minor_version;
 136
 137                         while (response == null
 138                                && exception_count < 5
 139                                 && ! Shutdown.ShutdownRequested) {
 140
 141                                 bool need_helper = false;
 142
 143                                 //Logger.Log.Debug ("Sending request!");
 144                                 try {
 145                                         response = request.Send () as RemoteIndexerResponse;
 146                                         //Logger.Log.Debug ("Done sending request");
 147                                 } catch (ResponseMessageException ex) {
 148                                         Logger.Log.Debug ("Caught ResponseMessageException: {0}", ex.Message);
 149
 150                                         if (ex.InnerException is System.Net.Sockets.SocketException) {
 151                                                 Logger.Log.Debug ("InnerException is SocketException -- we probably need to launch a helper");
 152                                                 need_helper = true;
 153                                         } else if (ex.InnerException is IOException) {
 154                                                 Logger.Log.Debug ("InnerException is IOException -- we probably need to launch a helper");
 155                                                 need_helper = true;
 156                                         } else {
 157                                                 Logger.Log.Debug (ex, "Exception was unexpected.");
 158                                         }
 159                                 }
 160
 161                                 // If we caught an exception...
 162                                 if (response == null) {
 163                                         if (! start_helper_by_hand || ! need_helper)
 164                                                 ++exception_count;
 165
 166                                         if (start_helper_by_hand) {
 167                                                 // Sleep briefly before trying again.
 168                                                 Thread.Sleep (1000);
 169                                         } else {
 170                                                 // Try to activate the helper.
 171                                                 LaunchHelper ();
 172                                         }
 173                                 }
 174                         }
 175
 176                         if (response == null && exception_count >= 5)
 177                                 Logger.Log.Error ("Exception limit exceeded trying to activate a helper.  Giving up on indexing!");
 178
 179                         return response;
 180                 }
 181
 182                 /////////////////////////////////////////////////////////
 183
 184                 static bool CheckHelper ()
 185                 {
 186                         string storage_dir = PathFinder.GetRemoteStorageDir (false);
 187
 188                         if (storage_dir == null)
 189                                 return false;
 190
 191                         // FIXME: We shouldn't need to know the path to the helper socket.
 192                         string socket_name = Path.Combine (storage_dir, "socket-helper");
 193
 194                         if (! File.Exists (socket_name))
 195                                 return false;
 196
 197                         // Open, and then immediately close, a connection to the helper's socket.
 198                         try {
 199                                 UnixClient test_client;
 200                                 test_client = new UnixClient (socket_name);
 201                                 test_client.Close ();
 202                                 return true;
 203                         } catch (Exception ex) {
 204                                 return false;
 205                         }
 206                 }
 207
 208                 static object helper_lock = new object ();
 209
 210                 static void LaunchHelper ()
 211                 {
 212                         // If we are in the process of shutting down, return immediately.
 213                         if (Shutdown.ShutdownRequested)
 214                                 return;
 215
 216                         lock (helper_lock) {
 217
 218                                 // If a helper appears to be running, return immediately.
 219                                 if (CheckHelper ())
 220                                         return;
 221
 222                                 Logger.Log.Debug ("Launching helper process");
 223
 224                                 SafeProcess p = new SafeProcess ();
 225                                 p.Arguments = new string [] { helper_path };
 226                                 p.Start ();
 227
 228                                 Logger.Log.Debug ("IndexHelper PID is {0}", p.Id);
 229
 230                                 // Poll the helper's socket.  Wait up to a minute
 231                                 // (500 ms * 120 times) for the helper to be ready
 232                                 // to handle requests.
 233                                 Stopwatch watch = new Stopwatch ();
 234                                 watch.Start ();
 235                                 int poll_count = 0;
 236                                 bool found_helper;
 237                                 do {
 238                                         Thread.Sleep (500);
 239                                         ++poll_count;
 240                                         found_helper = CheckHelper ();
 241                                 } while (poll_count < 120
 242                                          && ! found_helper
 243                                          && ! Shutdown.ShutdownRequested);
 244                                 watch.Stop ();
 245
 246                                 if (! found_helper)
 247                                         throw new Exception (String.Format ("Couldn't launch helper process {0}", p.Id));
 248
 249                                 Logger.Log.Debug ("Found IndexHelper ({0}) in {1}", p.Id, watch);
 250                                 helper_pid = p.Id;
 251                         }
 252                 }
 253
 254                 static public void SignalRemoteIndexer ()
 255                 {
 256                         // No helper running right now
 257                         if (helper_pid == -1 || ! CheckHelper ()) {
 258                                 helper_pid = -1;
 259                                 return;
 260                         }
 261
 262                         Mono.Unix.Native.Syscall.kill (helper_pid, Mono.Unix.Native.Signum.SIGUSR1);
 263                 }
 264         }
 265 }