Add PEP-249 dbapi module (#160)

Implemented dbapi2 interface in dbapi module. See [1] for details.
The main motivation for the module creation was the integration Django with
Tarantool database through django-tarantool database backend [2] which
requires dbapi connector to the database.

All the optional extensions and methods were ignored because Django does not
require them. Anyway, fell free to suggest its implementation as needed.

Unit tests were taken from dbapi-compliance [3] package.

Interactive transactions are not currently supported by Tarantool and
theirs implementation will be added in the connector when the feature is stable
it Tarantool itself.

[1] https://www.python.org/dev/peps/pep-0249/
[2] https://github.com/artembo/django-tarantool
[3] https://github.com/baztian/dbapi-compliance/

Co-authored-by: Denis Ignatenko <[email protected]>

Author: artembo

tarantool/__init__.py

@@ -75,4 +75,4 @@ def connectmesh(addrs=({'host': 'localhost', 'port': 3301},), user=None,
 
 __all__ = ['connect', 'Connection', 'connectmesh', 'MeshConnection', 'Schema',
            'Error', 'DatabaseError', 'NetworkError', 'NetworkWarning',
-           'SchemaError']
+           'SchemaError', 'dbapi']

tarantool/connection.py

@@ -18,7 +18,6 @@
 
 import msgpack
 
-import tarantool.error
 from tarantool.response import Response
 from tarantool.request import (
     Request,
@@ -50,12 +49,20 @@
     ITERATOR_ALL
 )
 from tarantool.error import (
+    Error,
     NetworkError,
     DatabaseError,
     InterfaceError,
     SchemaError,
     NetworkWarning,
+    OperationalError,
+    DataError,
+    IntegrityError,
+    InternalError,
+    ProgrammingError,
+    NotSupportedError,
     SchemaReloadException,
+    Warning,
     warn
 )
 from tarantool.schema import Schema
@@ -77,11 +84,20 @@ class Connection(object):
     Also this class provides low-level interface to data manipulation
     (insert/delete/update/select).
     '''
-    Error = tarantool.error
+    # DBAPI Extension: supply exceptions as attributes on the connection
+    Error = Error
     DatabaseError = DatabaseError
     InterfaceError = InterfaceError
     SchemaError = SchemaError
     NetworkError = NetworkError
+    Warning = Warning
+    DataError = DataError
+    OperationalError = OperationalError
+    IntegrityError = IntegrityError
+    InternalError = InternalError
+    ProgrammingError = ProgrammingError
+    NotSupportedError = NotSupportedError
+    ImproperlyConfigured = Exception
 
     def __init__(self, host, port,
                  user=None,
@@ -92,6 +108,7 @@ def __init__(self, host, port,
                  connect_now=True,
                  encoding=ENCODING_DEFAULT,
                  call_16=False,
+                 use_list=True,
                  connection_timeout=CONNECTION_TIMEOUT):
         '''
         Initialize a connection to the server.
@@ -124,6 +141,7 @@ def __init__(self, host, port,
         self._socket = None
         self.connected = False
         self.error = True
+        self.use_list = use_list
         self.encoding = encoding
         self.call_16 = call_16
         self.connection_timeout = connection_timeout
@@ -261,7 +279,7 @@ def _send_request_wo_reconnect(self, request):
         while True:
             try:
                 self._socket.sendall(bytes(request))
-                response = Response(self, self._read_response())
+                response = Response(self, self._read_response(), self.use_list)
                 break
             except SchemaReloadException as e:
                 self.update_schema(e.schema_version)
@@ -299,7 +317,6 @@ def check():  # Check that connection is alive
                     err = ctypes.get_last_error()
                     self._socket.setblocking(True)
 
-
                 WWSAEWOULDBLOCK = 10035
                 if (retbytes < 0) and (err == errno.EAGAIN or
                                        err == errno.EWOULDBLOCK or
@@ -446,7 +463,7 @@ def _join_v16(self, server_uuid):
         self._socket.sendall(bytes(request))
 
         while True:
-            resp = Response(self, self._read_response())
+            resp = Response(self, self._read_response(), self.use_list)
             yield resp
             if resp.code == REQUEST_TYPE_OK or resp.code >= REQUEST_TYPE_ERROR:
                 return
@@ -460,7 +477,7 @@ class JoinState:
         self._socket.sendall(bytes(request))
         state = JoinState.Handshake
         while True:
-            resp = Response(self, self._read_response())
+            resp = Response(self, self._read_response(), self.use_list)
             yield resp
             if resp.code >= REQUEST_TYPE_ERROR:
                 return
@@ -489,7 +506,7 @@ def subscribe(self, cluster_uuid, server_uuid, vclock=None):
         request = RequestSubscribe(self, cluster_uuid, server_uuid, vclock)
         self._socket.sendall(bytes(request))
         while True:
-            resp = Response(self, self._read_response())
+            resp = Response(self, self._read_response(), self.use_list)
             yield resp
             if resp.code >= REQUEST_TYPE_ERROR:
                 return
@@ -805,4 +822,4 @@ def execute(self, query, params=None):
             params = []
         request = RequestExecute(self, query, params)
         response = self._send_request(request)
-        return response
+        return response