[bug] do not allow concurrent schema creation

Moved schema creation and migrations to the pragma locked call, so we
avoid it running concurrently on a thread pool.

-- Resolves: #8945

2 files changed, 19 insertions, 10 deletions

diff --git a/src/leap/soledad/client/_db/blobs.py b/src/leap/soledad/client/_db/blobs.py
index cfabda74..1447e3bb 100644
--- a/src/leap/soledad/client/_db/blobs.py
+++ b/src/leap/soledad/client/_db/blobs.py
@@ -73,6 +73,20 @@ class SyncStatus:
 
 class ConnectionPool(adbapi.ConnectionPool):
 
+    def blocking_create_schema(self, create_schema_function):
+        """
+        Grabs a connection and executes schema creation from current thread,
+        disconnecting right after it. This ensures that schema creation blocks
+        everything and doesn't run concurrently.
+
+        :param create_schema_function: A function that receives a connection
+            and executes schema criation and/or migrations.
+        :type create_schema_function: function
+        """
+        conn = self.connect()
+        create_schema_function(conn)
+        self.disconnect(conn)
+
     def insertAndGetLastRowid(self, *args, **kwargs):
         """
         Execute an SQL query and return the last rowid.
@@ -439,8 +453,8 @@ class SQLiteBlobBackend(object):
         opts = sqlcipher.SQLCipherOptions(
             '/tmp/ignored', binascii.b2a_hex(key),
             is_raw_key=True, create=True)
-        pragmafun = partial(pragmas.set_init_pragmas, opts=opts)
-        openfun = _sqlcipherInitFactory(pragmafun)
+        openfun = partial(pragmas.set_init_pragmas, opts=opts,
+                          schema_func=_init_blob_table)
 
         self.dbpool = ConnectionPool(
             backend, self.path, check_same_thread=False, timeout=5,
@@ -553,13 +567,6 @@ def _init_blob_table(conn):
         conn.execute('ALTER TABLE blobs ADD COLUMN retries INT default 0')
 
 
-def _sqlcipherInitFactory(fun):
-    def _initialize(conn):
-        fun(conn)
-        _init_blob_table(conn)
-    return _initialize
-
-
 #
 # testing facilities
 #
diff --git a/src/leap/soledad/client/_db/pragmas.py b/src/leap/soledad/client/_db/pragmas.py
index 870ed63e..76fea458 100644
--- a/src/leap/soledad/client/_db/pragmas.py
+++ b/src/leap/soledad/client/_db/pragmas.py
@@ -31,7 +31,7 @@ logger = getLogger(__name__)
 _db_init_lock = threading.Lock()
 
 
-def set_init_pragmas(conn, opts=None, extra_queries=None):
+def set_init_pragmas(conn, opts=None, extra_queries=None, schema_func=None):
     """
     Set the initialization pragmas.
 
@@ -43,6 +43,8 @@ def set_init_pragmas(conn, opts=None, extra_queries=None):
     with _db_init_lock:
         # only one execution path should initialize the db
         _set_init_pragmas(conn, opts, extra_queries)
+        if schema_func:
+            schema_func(conn)
 
 
 def _set_init_pragmas(conn, opts, extra_queries):