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
  42                 string remote_index_name;
  43                 int remote_index_minor_version = 0;
  44                 int last_item_count = -1;
  45
  46                 static RemoteIndexer ()
  47                 {
  48                         string bihp = Environment.GetEnvironmentVariable ("_BEAGLED_INDEX_HELPER_PATH");
  49                         if (bihp == null)
  50                                 throw new Exception ("_BEAGLED_INDEX_HELPER_PATH not set!");
  51
  52                         helper_path = Path.GetFullPath (Path.Combine (bihp, "beagled-index-helper"));
  53                         if (! File.Exists (helper_path))
  54                                 throw new Exception ("Could not find " + helper_path);
  55                         Logger.Log.Debug ("Found index helper at {0}", helper_path);
  56                 }
  57
  58                 static public IIndexer NewRemoteIndexer (string name, int minor_version)
  59                 {
  60                         return new RemoteIndexer (name, minor_version);
  61                 }
  62
  63                 public RemoteIndexer (string name, int minor_version)
  64                 {
  65                         this.remote_index_name = name;
  66                         this.remote_index_minor_version = minor_version;
  67                 }
  68
  69                 public IndexerReceipt [] Flush (IndexerRequest request)
  70                 {
  71                         // If there isn't actually any work to do, just return
  72                         // an empty array.
  73                         if (request.IsEmpty)
  74                                 return new IndexerReceipt [0];
  75
  76                         // Iterate through the items in the IndexerRequest to
  77                         // store the streams before passing them to the helper.
  78                         foreach (Indexable indexable in request.Indexables) {
  79                                 if (indexable.Type == IndexableType.Add)
  80                                         indexable.StoreStream ();
  81                         }
  82
  83                         RemoteIndexerRequest remote_request;
  84                         remote_request = new RemoteIndexerRequest ();
  85                         remote_request.RemoteIndexName = this.remote_index_name;
  86                         remote_request.RemoteIndexMinorVersion = this.remote_index_minor_version;
  87                         remote_request.Request = request;
  88
  89                         RemoteIndexerResponse response;
  90                         response = SendRequest (remote_request);
  91
  92                         if (response == null) {
  93                                 Logger.Log.Error ("Something terrible happened --- Flush failed");
  94                                 request.Cleanup ();
  95                                 return null;
  96                         }
  97
  98                         last_item_count = response.ItemCount;
  99
 100                         return response.Receipts;
 101                 }
 102
 103                 public int GetItemCount ()
 104                 {
 105                         if (last_item_count == -1) {
 106                                 // Send an empty indexing request to cause the last item count to be
 107                                 // initialized.
 108                                 RemoteIndexerRequest request;
 109                                 request = new RemoteIndexerRequest ();
 110
 111                                 RemoteIndexerResponse response;
 112                                 response = SendRequest (request);
 113                                 if (response != null)
 114                                         last_item_count = response.ItemCount;
 115                                 else
 116                                         Logger.Log.Error ("Something terrible happened --- GetItemCount failed");
 117                         }
 118
 119                         return last_item_count;
 120                 }
 121
 122                 /////////////////////////////////////////////////////////
 123
 124                 private RemoteIndexerResponse SendRequest (RemoteIndexerRequest request)
 125                 {
 126                         RemoteIndexerResponse response = null;
 127                         int exception_count = 0;
 128                         bool start_helper_by_hand = false;
 129
 130                         if (Environment.GetEnvironmentVariable ("BEAGLE_RUN_HELPER_BY_HAND") != null)
 131                                 start_helper_by_hand = true;
 132
 133                         request.RemoteIndexName = remote_index_name;
 134                         request.RemoteIndexMinorVersion = remote_index_minor_version;
 135
 136                         while (response == null
 137                                && exception_count < 5
 138                                 && ! Shutdown.ShutdownRequested) {
 139
 140                                 bool need_helper = false;
 141
 142                                 //Logger.Log.Debug ("Sending request!");
 143                                 try {
 144                                         response = request.Send () as RemoteIndexerResponse;
 145                                         //Logger.Log.Debug ("Done sending request");
 146                                 } catch (ResponseMessageException ex) {
 147                                         Logger.Log.Debug ("Caught ResponseMessageException: {0}", ex.Message);
 148
 149                                         if (ex.InnerException is System.Net.Sockets.SocketException) {
 150                                                 Logger.Log.Debug ("InnerException is SocketException -- we probably need to launch a helper");
 151                                                 need_helper = true;
 152                                         } else if (ex.InnerException is IOException) {
 153                                                 Logger.Log.Debug ("InnerException is IOException -- we probably need to launch a helper");
 154                                                 need_helper = true;
 155                                         } else {
 156                                                 Logger.Log.Debug ("Exception was unexpected.  Details: {0}", ex);
 157                                         }
 158                                 }
 159
 160                                 // If we caught an exception...
 161                                 if (response == null) {
 162                                         if (! start_helper_by_hand || ! need_helper)
 163                                                 ++exception_count;
 164
 165                                         if (start_helper_by_hand) {
 166                                                 // Sleep briefly before trying again.
 167                                                 Thread.Sleep (1000);
 168                                         } else {
 169                                                 // Try to activate the helper.
 170                                                 LaunchHelper ();
 171                                         }
 172                                 }
 173                         }
 174
 175                         if (response == null && exception_count >= 5)
 176                                 Logger.Log.Error ("Exception limit exceeded trying to activate a helper.  Giving up on indexing!");
 177
 178                         return response;
 179                 }
 180
 181                 /////////////////////////////////////////////////////////
 182
 183                 static bool CheckHelper ()
 184                 {
 185                         string storage_dir = PathFinder.GetRemoteStorageDir (false);
 186
 187                         if (storage_dir == null)
 188                                 return false;
 189
 190                         // FIXME: We shouldn't need to know the path to the helper socket.
 191                         string socket_name = Path.Combine (storage_dir, "socket-helper");
 192
 193                         if (! File.Exists (socket_name))
 194                                 return false;
 195
 196                         // Open, and then immediately close, a connection to the helper's socket.
 197                         try {
 198                                 UnixClient test_client;
 199                                 test_client = new UnixClient (socket_name);
 200                                 test_client.Close ();
 201                                 return true;
 202                         } catch (Exception ex) {
 203                                 return false;
 204                         }
 205                 }
 206
 207                 static object helper_lock = new object ();
 208
 209                 static void LaunchHelper ()
 210                 {
 211                         // If we are in the process of shutting down, return immediately.
 212                         if (Shutdown.ShutdownRequested)
 213                                 return;
 214
 215                         lock (helper_lock) {
 216
 217                                 // If a helper appears to be running, return immediately.
 218                                 if (CheckHelper ())
 219                                         return;
 220
 221                                 Logger.Log.Debug ("Launching helper process");
 222
 223                                 Process p = new Process ();
 224                                 p.StartInfo.UseShellExecute = false;
 225                                 p.StartInfo.FileName = 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                         }
 251                 }
 252         }
 253 }