Retry opening the Xapian database if another process still has the lock

This should help with situations where the new gdatastore process is already
starting up (on a new session bus) while the old one is still busy shutting
down (see also: SL#1257).

1 files changed, 12 insertions, 2 deletions

diff --git a/gdatastore/index.py b/gdatastore/index.py
index c93f5b3..35491bf 100644
--- a/gdatastore/index.py
+++ b/gdatastore/index.py
@@ -19,6 +19,7 @@ Gdatastore metadata index interface
 import logging
 import os
 import sys
+import time
 
 import xapian
 from xapian import Document, Enquire, Query, WritableDatabase
@@ -320,8 +321,17 @@ class Index(object):
         database.close()
 
     def _migrate(self):
-        self._database = WritableDatabase(self._base_dir,
-                                          xapian.DB_CREATE_OR_OPEN)
+        for try_count in range(10):
+            try:
+                self._database = WritableDatabase(self._base_dir,
+                                                  xapian.DB_CREATE_OR_OPEN)
+            except xapian.DatabaseLockError:
+                logging.error("Couldn't lock Xapian database (try #%d)",
+                              try_count)
+                time.sleep(1)
+            else:
+                break
+
         version = int(self._database.get_metadata('gdatastore_version'))
 
         if version > _CURRENT_VERSION: