Fixed #10459 -- Refactored the internals of database connection objects so that connections know their own settings and pass around settings as dictionaries instead of passing around the Django settings module itself. This will make it easier for multiple database support. Thanks to Alex Gaynor for the initial patch.

This is backwards-compatible but will likely break third-party database backends. Specific API changes are:

* BaseDatabaseWrapper.__init__() now takes a settings_dict instead of a settings module. It's called settings_dict to disambiguate, and for easy grepability. This should be a dictionary containing DATABASE_NAME, etc.

* BaseDatabaseWrapper has a settings_dict attribute instead of an options attribute. BaseDatabaseWrapper.options is now BaseDatabaseWrapper['DATABASE_OPTIONS']

* BaseDatabaseWrapper._cursor() no longer takes a settings argument.

* BaseDatabaseClient.__init__() now takes a connection argument (a DatabaseWrapper instance) instead of no arguments.


git-svn-id: http://code.djangoproject.com/svn/django/trunk@10026 bcc190cf-cafb-0310-a4f2-bffc1f526a37

django/db/__init__.py

@@ -36,8 +36,22 @@ except ImportError, e:
         else:
             raise # If there's some other error, this must be an error in Django itself.
 
-# Convenient aliases for backend bits.
-connection = backend.DatabaseWrapper(**settings.DATABASE_OPTIONS)
+# `connection`, `DatabaseError` and `IntegrityError` are convenient aliases
+# for backend bits.
+
+# DatabaseWrapper.__init__() takes a dictionary, not a settings module, so
+# we manually create the dictionary from the settings, passing only the
+# settings that the database backends care about. Note that TIME_ZONE is used
+# by the PostgreSQL backends.
+connection = backend.DatabaseWrapper({
+    'DATABASE_HOST': settings.DATABASE_HOST,
+    'DATABASE_NAME': settings.DATABASE_NAME,
+    'DATABASE_OPTIONS': settings.DATABASE_OPTIONS,
+    'DATABASE_PASSWORD': settings.DATABASE_PASSWORD,
+    'DATABASE_PORT': settings.DATABASE_PORT,
+    'DATABASE_USER': settings.DATABASE_USER,
+    'TIME_ZONE': settings.TIME_ZONE,
+})
 DatabaseError = backend.DatabaseError
 IntegrityError = backend.IntegrityError
 

django/db/backends/__init__.py

@@ -24,10 +24,14 @@ class BaseDatabaseWrapper(local):
     Represents a database connection.
     """
     ops = None
-    def __init__(self, **kwargs):
+    def __init__(self, settings_dict):
+        # `settings_dict` should be a dictionary containing keys such as
+        # DATABASE_NAME, DATABASE_USER, etc. It's called `settings_dict`
+        # instead of `settings` to disambiguate it from Django settings
+        # modules.
         self.connection = None
         self.queries = []
-        self.options = kwargs
+        self.settings_dict = settings_dict
 
     def _commit(self):
         if self.connection is not None:
@@ -59,7 +63,7 @@ class BaseDatabaseWrapper(local):
 
     def cursor(self):
         from django.conf import settings
-        cursor = self._cursor(settings)
+        cursor = self._cursor()
         if settings.DEBUG:
             return self.make_debug_cursor(cursor)
         return cursor
@@ -498,6 +502,10 @@ class BaseDatabaseClient(object):
     # (e.g., "psql"). Subclasses must override this.
     executable_name = None
 
+    def __init__(self, connection):
+        # connection is an instance of BaseDatabaseWrapper.
+        self.connection = connection
+
     def runshell(self):
         raise NotImplementedError()
 

django/db/backends/dummy/base.py

@@ -46,7 +46,7 @@ class DatabaseWrapper(object):
 
         self.features = BaseDatabaseFeatures()
         self.ops = DatabaseOperations()
-        self.client = DatabaseClient()
+        self.client = DatabaseClient(self)
         self.creation = BaseDatabaseCreation(self)
         self.introspection = DatabaseIntrospection(self)
         self.validation = BaseDatabaseValidation()

django/db/backends/mysql/base.py

@@ -234,11 +234,11 @@ class DatabaseWrapper(BaseDatabaseWrapper):
 
     def __init__(self, **kwargs):
         super(DatabaseWrapper, self).__init__(**kwargs)
-        self.server_version = None
 
+        self.server_version = None
         self.features = DatabaseFeatures()
         self.ops = DatabaseOperations()
-        self.client = DatabaseClient()
+        self.client = DatabaseClient(self)
         self.creation = DatabaseCreation(self)
         self.introspection = DatabaseIntrospection(self)
         self.validation = DatabaseValidation()
@@ -253,26 +253,27 @@ class DatabaseWrapper(BaseDatabaseWrapper):
                 self.connection = None
         return False
 
-    def _cursor(self, settings):
+    def _cursor(self):
         if not self._valid_connection():
             kwargs = {
                 'conv': django_conversions,
                 'charset': 'utf8',
                 'use_unicode': True,
             }
-            if settings.DATABASE_USER:
-                kwargs['user'] = settings.DATABASE_USER
-            if settings.DATABASE_NAME:
-                kwargs['db'] = settings.DATABASE_NAME
-            if settings.DATABASE_PASSWORD:
-                kwargs['passwd'] = settings.DATABASE_PASSWORD
-            if settings.DATABASE_HOST.startswith('/'):
-                kwargs['unix_socket'] = settings.DATABASE_HOST
-            elif settings.DATABASE_HOST:
-                kwargs['host'] = settings.DATABASE_HOST
-            if settings.DATABASE_PORT:
-                kwargs['port'] = int(settings.DATABASE_PORT)
-            kwargs.update(self.options)
+            settings_dict = self.settings_dict
+            if settings_dict['DATABASE_USER']:
+                kwargs['user'] = settings_dict['DATABASE_USER']
+            if settings_dict['DATABASE_NAME']:
+                kwargs['db'] = settings_dict['DATABASE_NAME']
+            if settings_dict['DATABASE_PASSWORD']:
+                kwargs['passwd'] = settings_dict['DATABASE_PASSWORD']
+            if settings_dict['DATABASE_HOST'].startswith('/'):
+                kwargs['unix_socket'] = settings_dict['DATABASE_HOST']
+            elif settings_dict['DATABASE_HOST']:
+                kwargs['host'] = settings_dict['DATABASE_HOST']
+            if settings_dict['DATABASE_PORT']:
+                kwargs['port'] = int(settings_dict['DATABASE_PORT'])
+            kwargs.update(settings_dict['DATABASE_OPTIONS'])
             self.connection = Database.connect(**kwargs)
             self.connection.encoders[SafeUnicode] = self.connection.encoders[unicode]
             self.connection.encoders[SafeString] = self.connection.encoders[str]

django/db/backends/mysql/client.py

@@ -1,18 +1,18 @@
 from django.db.backends import BaseDatabaseClient
-from django.conf import settings
 import os
 
 class DatabaseClient(BaseDatabaseClient):
     executable_name = 'mysql'
 
     def runshell(self):
+        settings_dict = self.connection.settings_dict
         args = ['']
-        db = settings.DATABASE_OPTIONS.get('db', settings.DATABASE_NAME)
-        user = settings.DATABASE_OPTIONS.get('user', settings.DATABASE_USER)
-        passwd = settings.DATABASE_OPTIONS.get('passwd', settings.DATABASE_PASSWORD)
-        host = settings.DATABASE_OPTIONS.get('host', settings.DATABASE_HOST)
-        port = settings.DATABASE_OPTIONS.get('port', settings.DATABASE_PORT)
-        defaults_file = settings.DATABASE_OPTIONS.get('read_default_file')
+        db = settings_dict['DATABASE_OPTIONS'].get('db', settings_dict['DATABASE_NAME'])
+        user = settings_dict['DATABASE_OPTIONS'].get('user', settings_dict['DATABASE_USER'])
+        passwd = settings_dict['DATABASE_OPTIONS'].get('passwd', settings_dict['DATABASE_PASSWORD'])
+        host = settings_dict['DATABASE_OPTIONS'].get('host', settings_dict['DATABASE_HOST'])
+        port = settings_dict['DATABASE_OPTIONS'].get('port', settings_dict['DATABASE_PORT'])
+        defaults_file = settings_dict['DATABASE_OPTIONS'].get('read_default_file')
         # Seems to be no good way to set sql_mode with CLI.
     
         if defaults_file:

django/db/backends/oracle/base.py

@@ -262,7 +262,7 @@ class DatabaseWrapper(BaseDatabaseWrapper):
 
         self.features = DatabaseFeatures()
         self.ops = DatabaseOperations()
-        self.client = DatabaseClient()
+        self.client = DatabaseClient(self)
         self.creation = DatabaseCreation(self)
         self.introspection = DatabaseIntrospection(self)
         self.validation = BaseDatabaseValidation()
@@ -270,23 +270,24 @@ class DatabaseWrapper(BaseDatabaseWrapper):
     def _valid_connection(self):
         return self.connection is not None
 
-    def _connect_string(self, settings):
-        if len(settings.DATABASE_HOST.strip()) == 0:
-            settings.DATABASE_HOST = 'localhost'
-        if len(settings.DATABASE_PORT.strip()) != 0:
-            dsn = Database.makedsn(settings.DATABASE_HOST,
-                                   int(settings.DATABASE_PORT),
-                                   settings.DATABASE_NAME)
+    def _connect_string(self):
+        settings_dict = self.settings_dict
+        if len(settings_dict['DATABASE_HOST'].strip()) == 0:
+            settings_dict['DATABASE_HOST'] = 'localhost'
+        if len(settings_dict['DATABASE_PORT'].strip()) != 0:
+            dsn = Database.makedsn(settings_dict['DATABASE_HOST'],
+                                   int(settings_dict['DATABASE_PORT']),
+                                   settings_dict['DATABASE_NAME'])
         else:
-            dsn = settings.DATABASE_NAME
-        return "%s/%s@%s" % (settings.DATABASE_USER,
-                             settings.DATABASE_PASSWORD, dsn)
+            dsn = settings_dict['DATABASE_NAME']
+        return "%s/%s@%s" % (settings_dict['DATABASE_USER'],
+                             settings_dict['DATABASE_PASSWORD'], dsn)
 
-    def _cursor(self, settings):
+    def _cursor(self):
         cursor = None
         if not self._valid_connection():
-            conn_string = self._connect_string(settings)
-            self.connection = Database.connect(conn_string, **self.options)
+            conn_string = self._connect_string()
+            self.connection = Database.connect(conn_string, **self.settings_dict['DATABASE_OPTIONS'])
             cursor = FormatStylePlaceholderCursor(self.connection)
             # Set oracle date to ansi date format.  This only needs to execute
             # once when we create a new connection. We also set the Territory

django/db/backends/oracle/client.py

@@ -1,12 +1,10 @@
 from django.db.backends import BaseDatabaseClient
-from django.conf import settings
 import os
 
 class DatabaseClient(BaseDatabaseClient):
     executable_name = 'sqlplus'
 
     def runshell(self):
-        from django.db import connection
-        conn_string = connection._connect_string(settings)
+        conn_string = self.connection._connect_string()
         args = [self.executable_name, "-L", conn_string]
         os.execvp(self.executable_name, args)

django/db/backends/postgresql/base.py

@@ -90,32 +90,33 @@ class DatabaseWrapper(BaseDatabaseWrapper):
 
         self.features = DatabaseFeatures()
         self.ops = DatabaseOperations()
-        self.client = DatabaseClient()
+        self.client = DatabaseClient(self)
         self.creation = DatabaseCreation(self)
         self.introspection = DatabaseIntrospection(self)
         self.validation = BaseDatabaseValidation()
 
-    def _cursor(self, settings):
+    def _cursor(self):
         set_tz = False
+        settings_dict = self.settings_dict
         if self.connection is None:
             set_tz = True
-            if settings.DATABASE_NAME == '':
+            if settings_dict['DATABASE_NAME'] == '':
                 from django.core.exceptions import ImproperlyConfigured
                 raise ImproperlyConfigured("You need to specify DATABASE_NAME in your Django settings file.")
-            conn_string = "dbname=%s" % settings.DATABASE_NAME
-            if settings.DATABASE_USER:
-                conn_string = "user=%s %s" % (settings.DATABASE_USER, conn_string)
-            if settings.DATABASE_PASSWORD:
-                conn_string += " password='%s'" % settings.DATABASE_PASSWORD
-            if settings.DATABASE_HOST:
-                conn_string += " host=%s" % settings.DATABASE_HOST
-            if settings.DATABASE_PORT:
-                conn_string += " port=%s" % settings.DATABASE_PORT
-            self.connection = Database.connect(conn_string, **self.options)
+            conn_string = "dbname=%s" % settings_dict['DATABASE_NAME']
+            if settings_dict['DATABASE_USER']:
+                conn_string = "user=%s %s" % (settings_dict['DATABASE_USER'], conn_string)
+            if settings_dict['DATABASE_PASSWORD']:
+                conn_string += " password='%s'" % settings_dict['DATABASE_PASSWORD']
+            if settings_dict['DATABASE_HOST']:
+                conn_string += " host=%s" % settings_dict['DATABASE_HOST']
+            if settings_dict['DATABASE_PORT']:
+                conn_string += " port=%s" % settings_dict['DATABASE_PORT']
+            self.connection = Database.connect(conn_string, **settings_dict['DATABASE_OPTIONS'])
             self.connection.set_isolation_level(1) # make transactions transparent to all cursors
         cursor = self.connection.cursor()
         if set_tz:
-            cursor.execute("SET TIME ZONE %s", [settings.TIME_ZONE])
+            cursor.execute("SET TIME ZONE %s", [settings_dict['TIME_ZONE']])
             if not hasattr(self, '_version'):
                 self.__class__._version = get_version(cursor)
             if self._version < (8, 0):

django/db/backends/postgresql/client.py

@@ -1,19 +1,19 @@
 from django.db.backends import BaseDatabaseClient
-from django.conf import settings
 import os
 
 class DatabaseClient(BaseDatabaseClient):
     executable_name = 'psql'
 
     def runshell(self):
+        settings_dict = self.connection.settings_dict
         args = [self.executable_name]
-        if settings.DATABASE_USER:
-            args += ["-U", settings.DATABASE_USER]
-        if settings.DATABASE_PASSWORD:
+        if settings_dict['DATABASE_USER']:
+            args += ["-U", settings_dict['DATABASE_USER']]
+        if settings_dict['DATABASE_PASSWORD']:
             args += ["-W"]
-        if settings.DATABASE_HOST:
-            args.extend(["-h", settings.DATABASE_HOST])
-        if settings.DATABASE_PORT:
-            args.extend(["-p", str(settings.DATABASE_PORT)])
-        args += [settings.DATABASE_NAME]
+        if settings_dict['DATABASE_HOST']:
+            args.extend(["-h", settings_dict['DATABASE_HOST']])
+        if settings_dict['DATABASE_PORT']:
+            args.extend(["-p", str(settings_dict['DATABASE_PORT'])])
+        args += [settings_dict['DATABASE_NAME']]
         os.execvp(self.executable_name, args)

django/db/backends/postgresql_psycopg2/base.py

@@ -60,37 +60,38 @@ class DatabaseWrapper(BaseDatabaseWrapper):
         
         self.features = DatabaseFeatures()
         self.ops = DatabaseOperations()
-        self.client = DatabaseClient()
+        self.client = DatabaseClient(self)
         self.creation = DatabaseCreation(self)
         self.introspection = DatabaseIntrospection(self)
         self.validation = BaseDatabaseValidation()
 
-    def _cursor(self, settings):
+    def _cursor(self):
         set_tz = False
+        settings_dict = self.settings_dict
         if self.connection is None:
             set_tz = True
-            if settings.DATABASE_NAME == '':
+            if settings_dict['DATABASE_NAME'] == '':
                 from django.core.exceptions import ImproperlyConfigured
                 raise ImproperlyConfigured("You need to specify DATABASE_NAME in your Django settings file.")
             conn_params = {
-                'database': settings.DATABASE_NAME,
+                'database': settings_dict['DATABASE_NAME'],
             }
-            conn_params.update(self.options)
-            if settings.DATABASE_USER:
-                conn_params['user'] = settings.DATABASE_USER
-            if settings.DATABASE_PASSWORD:
-                conn_params['password'] = settings.DATABASE_PASSWORD
-            if settings.DATABASE_HOST:
-                conn_params['host'] = settings.DATABASE_HOST
-            if settings.DATABASE_PORT:
-                conn_params['port'] = settings.DATABASE_PORT
+            conn_params.update(settings_dict['DATABASE_OPTIONS'])
+            if settings_dict['DATABASE_USER']:
+                conn_params['user'] = settings_dict['DATABASE_USER']
+            if settings_dict['DATABASE_PASSWORD']:
+                conn_params['password'] = settings_dict['DATABASE_PASSWORD']
+            if settings_dict['DATABASE_HOST']:
+                conn_params['host'] = settings_dict['DATABASE_HOST']
+            if settings_dict['DATABASE_PORT']:
+                conn_params['port'] = settings_dict['DATABASE_PORT']
             self.connection = Database.connect(**conn_params)
             self.connection.set_isolation_level(1) # make transactions transparent to all cursors
             self.connection.set_client_encoding('UTF8')
         cursor = self.connection.cursor()
         cursor.tzinfo_factory = None
         if set_tz:
-            cursor.execute("SET TIME ZONE %s", [settings.TIME_ZONE])
+            cursor.execute("SET TIME ZONE %s", [settings_dict['TIME_ZONE']])
             if not hasattr(self, '_version'):
                 self.__class__._version = get_version(cursor)
             if self._version < (8, 0):

django/db/backends/sqlite3/base.py

@@ -149,21 +149,22 @@ class DatabaseWrapper(BaseDatabaseWrapper):
 
         self.features = DatabaseFeatures()
         self.ops = DatabaseOperations()
-        self.client = DatabaseClient()
+        self.client = DatabaseClient(self)
         self.creation = DatabaseCreation(self)
         self.introspection = DatabaseIntrospection(self)
         self.validation = BaseDatabaseValidation()
 
-    def _cursor(self, settings):
+    def _cursor(self):
         if self.connection is None:
-            if not settings.DATABASE_NAME:
+            settings_dict = self.settings_dict
+            if not settings_dict['DATABASE_NAME']:
                 from django.core.exceptions import ImproperlyConfigured
                 raise ImproperlyConfigured, "Please fill out DATABASE_NAME in the settings module before using the database."
             kwargs = {
-                'database': settings.DATABASE_NAME,
+                'database': settings_dict['DATABASE_NAME'],
                 'detect_types': Database.PARSE_DECLTYPES | Database.PARSE_COLNAMES,
             }
-            kwargs.update(self.options)
+            kwargs.update(settings_dict['DATABASE_OPTIONS'])
             self.connection = Database.connect(**kwargs)
             # Register extract, date_trunc, and regexp functions.
             self.connection.create_function("django_extract", 2, _sqlite_extract)
@@ -172,11 +173,10 @@ class DatabaseWrapper(BaseDatabaseWrapper):
         return self.connection.cursor(factory=SQLiteCursorWrapper)
 
     def close(self):
-        from django.conf import settings
         # If database is in memory, closing the connection destroys the
         # database. To prevent accidental data loss, ignore close requests on
         # an in-memory db.
-        if settings.DATABASE_NAME != ":memory:":
+        if self.settings_dict['DATABASE_NAME'] != ":memory:":
             BaseDatabaseWrapper.close(self)
 
 class SQLiteCursorWrapper(Database.Cursor):

django/db/backends/sqlite3/client.py

@@ -1,10 +1,9 @@
 from django.db.backends import BaseDatabaseClient
-from django.conf import settings
 import os
 
 class DatabaseClient(BaseDatabaseClient):
     executable_name = 'sqlite3'
 
     def runshell(self):
-        args = ['', settings.DATABASE_NAME]
+        args = ['', self.connection.settings_dict['DATABASE_NAME']]
         os.execvp(self.executable_name, args)