Refactored database exceptions wrapping.

Squashed commit of the following:

commit 2181d833ed1a2e422494738dcef311164c4e097e
Author: Aymeric Augustin <aymeric.augustin@m4x.org>
Date:   Wed Feb 27 14:28:39 2013 +0100

    Fixed #15901 -- Wrapped all PEP-249 exceptions.

commit 5476a5d93c19aa2f928c497d39ce6e33f52694e2
Author: Aymeric Augustin <aymeric.augustin@m4x.org>
Date:   Tue Feb 26 17:26:52 2013 +0100

    Added PEP 3134 exception chaining.

    Thanks Jacob Kaplan-Moss for the suggestion.

commit 9365fad0a650328002fb424457d675a273c95802
Author: Aymeric Augustin <aymeric.augustin@m4x.org>
Date:   Tue Feb 26 17:13:49 2013 +0100

    Improved API for wrapping database errors.

    Thanks Alex Gaynor for the proposal.

commit 1b463b765f2826f73a8d9266795cd5da4f8d5e9e
Author: Aymeric Augustin <aymeric.augustin@m4x.org>
Date:   Tue Feb 26 15:00:39 2013 +0100

    Removed redundant exception wrapping.

    This is now taken care of by the cursor wrapper.

commit 524bc7345a724bf526bdd2dd1bcf5ede67d6bb5c
Author: Aymeric Augustin <aymeric.augustin@m4x.org>
Date:   Tue Feb 26 14:55:10 2013 +0100

    Wrapped database exceptions in the base backend.

    This covers the most common PEP-249 APIs:
    - Connection APIs: close(), commit(), rollback(), cursor()
    - Cursor APIs: callproc(), close(), execute(), executemany(),
      fetchone(), fetchmany(), fetchall(), nextset().

    Fixed #19920.

commit a66746bb5f0839f35543222787fce3b6a0d0a3ea
Author: Aymeric Augustin <aymeric.augustin@m4x.org>
Date:   Tue Feb 26 14:53:34 2013 +0100

    Added a wrap_database_exception context manager and decorator.

    It re-throws backend-specific exceptions using Django's common wrappers.
This commit is contained in:
Aymeric Augustin 2013-02-26 14:53:34 +01:00
parent 50328f0a61
commit 59a3520875
10 changed files with 147 additions and 100 deletions

View File

@ -1,8 +1,11 @@
from django.conf import settings
from django.core import signals
from django.core.exceptions import ImproperlyConfigured
from django.db.utils import (ConnectionHandler, ConnectionRouter,
load_backend, DEFAULT_DB_ALIAS, DatabaseError, IntegrityError)
from django.db.utils import (DEFAULT_DB_ALIAS,
DataError, OperationalError, IntegrityError, InternalError,
ProgrammingError, NotSupportedError, DatabaseError,
InterfaceError, Error,
load_backend, ConnectionHandler, ConnectionRouter)
__all__ = ('backend', 'connection', 'connections', 'router', 'DatabaseError',
'IntegrityError', 'DEFAULT_DB_ALIAS')

View File

@ -14,6 +14,7 @@ from django.db import DEFAULT_DB_ALIAS
from django.db.backends.signals import connection_created
from django.db.backends import util
from django.db.transaction import TransactionManagementError
from django.db.utils import DatabaseErrorWrapper
from django.utils.functional import cached_property
from django.utils.importlib import import_module
from django.utils import six
@ -57,6 +58,9 @@ class BaseDatabaseWrapper(object):
def __hash__(self):
return hash(self.alias)
def wrap_database_errors(self):
return DatabaseErrorWrapper(self.Database)
def get_connection_params(self):
raise NotImplementedError
@ -70,6 +74,7 @@ class BaseDatabaseWrapper(object):
raise NotImplementedError
def _cursor(self):
with self.wrap_database_errors():
if self.connection is None:
conn_params = self.get_connection_params()
self.connection = self.get_new_connection(conn_params)
@ -79,12 +84,19 @@ class BaseDatabaseWrapper(object):
def _commit(self):
if self.connection is not None:
with self.wrap_database_errors():
return self.connection.commit()
def _rollback(self):
if self.connection is not None:
with self.wrap_database_errors():
return self.connection.rollback()
def _close(self):
if self.connection is not None:
with self.wrap_database_errors():
return self.connection.close()
def _enter_transaction_management(self, managed):
"""
A hook for backend-specific changes required when entering manual
@ -333,8 +345,9 @@ class BaseDatabaseWrapper(object):
def close(self):
self.validate_thread_sharing()
if self.connection is not None:
self.connection.close()
try:
self._close()
finally:
self.connection = None
self.set_clean()

View File

@ -116,30 +116,22 @@ class CursorWrapper(object):
def execute(self, query, args=None):
try:
return self.cursor.execute(query, args)
except Database.IntegrityError as e:
six.reraise(utils.IntegrityError, utils.IntegrityError(*tuple(e.args)), sys.exc_info()[2])
except Database.OperationalError as e:
# Map some error codes to IntegrityError, since they seem to be
# misclassified and Django would prefer the more logical place.
if e[0] in self.codes_for_integrityerror:
six.reraise(utils.IntegrityError, utils.IntegrityError(*tuple(e.args)), sys.exc_info()[2])
six.reraise(utils.DatabaseError, utils.DatabaseError(*tuple(e.args)), sys.exc_info()[2])
except Database.DatabaseError as e:
six.reraise(utils.DatabaseError, utils.DatabaseError(*tuple(e.args)), sys.exc_info()[2])
raise
def executemany(self, query, args):
try:
return self.cursor.executemany(query, args)
except Database.IntegrityError as e:
six.reraise(utils.IntegrityError, utils.IntegrityError(*tuple(e.args)), sys.exc_info()[2])
except Database.OperationalError as e:
# Map some error codes to IntegrityError, since they seem to be
# misclassified and Django would prefer the more logical place.
if e[0] in self.codes_for_integrityerror:
six.reraise(utils.IntegrityError, utils.IntegrityError(*tuple(e.args)), sys.exc_info()[2])
six.reraise(utils.DatabaseError, utils.DatabaseError(*tuple(e.args)), sys.exc_info()[2])
except Database.DatabaseError as e:
six.reraise(utils.DatabaseError, utils.DatabaseError(*tuple(e.args)), sys.exc_info()[2])
raise
def __getattr__(self, attr):
if attr in self.__dict__:
@ -391,6 +383,8 @@ class DatabaseWrapper(BaseDatabaseWrapper):
'iendswith': 'LIKE %s',
}
Database = Database
def __init__(self, *args, **kwargs):
super(DatabaseWrapper, self).__init__(*args, **kwargs)

View File

@ -501,6 +501,8 @@ class DatabaseWrapper(BaseDatabaseWrapper):
'iendswith': "LIKEC UPPER(%s) ESCAPE '\\'",
})
Database = Database
def __init__(self, *args, **kwargs):
super(DatabaseWrapper, self).__init__(*args, **kwargs)
@ -604,10 +606,6 @@ class DatabaseWrapper(BaseDatabaseWrapper):
if self.connection is not None:
try:
return self.connection.commit()
except Database.IntegrityError as e:
# In case cx_Oracle implements (now or in a future version)
# raising this specific exception
six.reraise(utils.IntegrityError, utils.IntegrityError(*tuple(e.args)), sys.exc_info()[2])
except Database.DatabaseError as e:
# cx_Oracle 5.0.4 raises a cx_Oracle.DatabaseError exception
# with the following attributes and values:
@ -620,7 +618,7 @@ class DatabaseWrapper(BaseDatabaseWrapper):
if hasattr(x, 'code') and hasattr(x, 'message') \
and x.code == 2091 and 'ORA-02291' in x.message:
six.reraise(utils.IntegrityError, utils.IntegrityError(*tuple(e.args)), sys.exc_info()[2])
six.reraise(utils.DatabaseError, utils.DatabaseError(*tuple(e.args)), sys.exc_info()[2])
raise
@cached_property
def oracle_version(self):
@ -760,13 +758,11 @@ class FormatStylePlaceholderCursor(object):
self._guess_input_sizes([params])
try:
return self.cursor.execute(query, self._param_generator(params))
except Database.IntegrityError as e:
six.reraise(utils.IntegrityError, utils.IntegrityError(*tuple(e.args)), sys.exc_info()[2])
except Database.DatabaseError as e:
# cx_Oracle <= 4.4.0 wrongly raises a DatabaseError for ORA-01400.
if hasattr(e.args[0], 'code') and e.args[0].code == 1400 and not isinstance(e, IntegrityError):
six.reraise(utils.IntegrityError, utils.IntegrityError(*tuple(e.args)), sys.exc_info()[2])
six.reraise(utils.DatabaseError, utils.DatabaseError(*tuple(e.args)), sys.exc_info()[2])
raise
def executemany(self, query, params=None):
# cx_Oracle doesn't support iterators, convert them to lists
@ -789,13 +785,11 @@ class FormatStylePlaceholderCursor(object):
try:
return self.cursor.executemany(query,
[self._param_generator(p) for p in formatted])
except Database.IntegrityError as e:
six.reraise(utils.IntegrityError, utils.IntegrityError(*tuple(e.args)), sys.exc_info()[2])
except Database.DatabaseError as e:
# cx_Oracle <= 4.4.0 wrongly raises a DatabaseError for ORA-01400.
if hasattr(e.args[0], 'code') and e.args[0].code == 1400 and not isinstance(e, IntegrityError):
six.reraise(utils.IntegrityError, utils.IntegrityError(*tuple(e.args)), sys.exc_info()[2])
six.reraise(utils.DatabaseError, utils.DatabaseError(*tuple(e.args)), sys.exc_info()[2])
raise
def fetchone(self):
row = self.cursor.fetchone()

View File

@ -40,40 +40,6 @@ def utc_tzinfo_factory(offset):
raise AssertionError("database connection isn't set to UTC")
return utc
class CursorWrapper(object):
"""
A thin wrapper around psycopg2's normal cursor class so that we can catch
particular exception instances and reraise them with the right types.
"""
def __init__(self, cursor):
self.cursor = cursor
def execute(self, query, args=None):
try:
return self.cursor.execute(query, args)
except Database.IntegrityError as e:
six.reraise(utils.IntegrityError, utils.IntegrityError(*tuple(e.args)), sys.exc_info()[2])
except Database.DatabaseError as e:
six.reraise(utils.DatabaseError, utils.DatabaseError(*tuple(e.args)), sys.exc_info()[2])
def executemany(self, query, args):
try:
return self.cursor.executemany(query, args)
except Database.IntegrityError as e:
six.reraise(utils.IntegrityError, utils.IntegrityError(*tuple(e.args)), sys.exc_info()[2])
except Database.DatabaseError as e:
six.reraise(utils.DatabaseError, utils.DatabaseError(*tuple(e.args)), sys.exc_info()[2])
def __getattr__(self, attr):
if attr in self.__dict__:
return self.__dict__[attr]
else:
return getattr(self.cursor, attr)
def __iter__(self):
return iter(self.cursor)
class DatabaseFeatures(BaseDatabaseFeatures):
needs_datetime_string_cast = False
can_return_id_from_insert = True
@ -106,6 +72,8 @@ class DatabaseWrapper(BaseDatabaseWrapper):
'iendswith': 'LIKE UPPER(%s)',
}
Database = Database
def __init__(self, *args, **kwargs):
super(DatabaseWrapper, self).__init__(*args, **kwargs)
@ -207,7 +175,7 @@ class DatabaseWrapper(BaseDatabaseWrapper):
def create_cursor(self):
cursor = self.connection.cursor()
cursor.tzinfo_factory = utc_tzinfo_factory if settings.USE_TZ else None
return CursorWrapper(cursor)
return cursor
def _enter_transaction_management(self, managed):
"""
@ -245,10 +213,3 @@ class DatabaseWrapper(BaseDatabaseWrapper):
if ((self.transaction_state and self.transaction_state[-1]) or
not self.features.uses_autocommit):
super(DatabaseWrapper, self).set_dirty()
def _commit(self):
if self.connection is not None:
try:
return self.connection.commit()
except Database.IntegrityError as e:
six.reraise(utils.IntegrityError, utils.IntegrityError(*tuple(e.args)), sys.exc_info()[2])

View File

@ -10,7 +10,6 @@ import datetime
import decimal
import warnings
import re
import sys
from django.db import utils
from django.db.backends import *
@ -291,6 +290,8 @@ class DatabaseWrapper(BaseDatabaseWrapper):
'iendswith': "LIKE %s ESCAPE '\\'",
}
Database = Database
def __init__(self, *args, **kwargs):
super(DatabaseWrapper, self).__init__(*args, **kwargs)
@ -398,21 +399,11 @@ class SQLiteCursorWrapper(Database.Cursor):
"""
def execute(self, query, params=()):
query = self.convert_query(query)
try:
return Database.Cursor.execute(self, query, params)
except Database.IntegrityError as e:
six.reraise(utils.IntegrityError, utils.IntegrityError(*tuple(e.args)), sys.exc_info()[2])
except Database.DatabaseError as e:
six.reraise(utils.DatabaseError, utils.DatabaseError(*tuple(e.args)), sys.exc_info()[2])
def executemany(self, query, param_list):
query = self.convert_query(query)
try:
return Database.Cursor.executemany(self, query, param_list)
except Database.IntegrityError as e:
six.reraise(utils.IntegrityError, utils.IntegrityError(*tuple(e.args)), sys.exc_info()[2])
except Database.DatabaseError as e:
six.reraise(utils.DatabaseError, utils.DatabaseError(*tuple(e.args)), sys.exc_info()[2])
def convert_query(self, query):
return FORMAT_QMARK_REGEX.sub('?', query).replace('%%', '%')

View File

@ -22,7 +22,12 @@ class CursorWrapper(object):
def __getattr__(self, attr):
if attr in ('execute', 'executemany', 'callproc'):
self.db.set_dirty()
return getattr(self.cursor, attr)
cursor_attr = getattr(self.cursor, attr)
if attr in ('callproc', 'close', 'execute', 'executemany',
'fetchone', 'fetchmany', 'fetchall', 'nextset'):
return self.db.wrap_database_errors()(cursor_attr)
else:
return cursor_attr
def __iter__(self):
return iter(self.cursor)
@ -34,6 +39,7 @@ class CursorDebugWrapper(CursorWrapper):
self.db.set_dirty()
start = time()
try:
with self.db.wrap_database_errors():
return self.cursor.execute(sql, params)
finally:
stop = time()
@ -51,6 +57,7 @@ class CursorDebugWrapper(CursorWrapper):
self.db.set_dirty()
start = time()
try:
with self.db.wrap_database_errors():
return self.cursor.executemany(sql, param_list)
finally:
stop = time()

View File

@ -1,3 +1,4 @@
from functools import wraps
import os
import pkgutil
from threading import local
@ -12,16 +13,87 @@ from django.utils import six
DEFAULT_DB_ALIAS = 'default'
# Define some exceptions that mirror the PEP249 interface.
# We will rethrow any backend-specific errors using these
# common wrappers
class DatabaseError(Exception):
class Error(StandardError):
pass
class InterfaceError(Error):
pass
class DatabaseError(Error):
pass
class DataError(DatabaseError):
pass
class OperationalError(DatabaseError):
pass
class IntegrityError(DatabaseError):
pass
class InternalError(DatabaseError):
pass
class ProgrammingError(DatabaseError):
pass
class NotSupportedError(DatabaseError):
pass
class DatabaseErrorWrapper(object):
"""
Context manager and decorator that re-throws backend-specific database
exceptions using Django's common wrappers.
"""
def __init__(self, database):
"""
database is a module defining PEP-249 exceptions.
"""
self.database = database
def __enter__(self):
pass
def __exit__(self, exc_type, exc_value, traceback):
if exc_type is None:
return
for dj_exc_type in (
DataError,
OperationalError,
IntegrityError,
InternalError,
ProgrammingError,
NotSupportedError,
DatabaseError,
InterfaceError,
Error,
):
db_exc_type = getattr(self.database, dj_exc_type.__name__)
if issubclass(exc_type, db_exc_type):
dj_exc_value = dj_exc_type(*tuple(exc_value.args))
if six.PY3:
dj_exc_value.__cause__ = exc_value
six.reraise(dj_exc_type, dj_exc_value, traceback)
def __call__(self, func):
@wraps(func)
def inner(*args, **kwargs):
with self:
return func(*args, **kwargs)
return inner
def load_backend(backend_name):
# Look for a fully qualified database backend name
try:

View File

@ -119,18 +119,28 @@ NoReverseMatch
Database Exceptions
===================
Django wraps the standard database exceptions :exc:`DatabaseError` and
:exc:`IntegrityError` so that your Django code has a guaranteed common
implementation of these classes. These database exceptions are
provided in :mod:`django.db`.
Django wraps the standard database exceptions so that your Django code has a
guaranteed common implementation of these classes. These database exceptions
are provided in :mod:`django.db`.
.. exception:: Error
.. exception:: InterfaceError
.. exception:: DatabaseError
.. exception:: DataError
.. exception:: OperationalError
.. exception:: IntegrityError
.. exception:: InternalError
.. exception:: ProgrammingError
.. exception:: NotSupportedError
The Django wrappers for database exceptions behave exactly the same as
the underlying database exceptions. See :pep:`249`, the Python Database API
Specification v2.0, for further information.
.. versionchanged:: 1.6
Previous version of Django only wrapped ``DatabaseError`` and
``IntegrityError``.
.. exception:: models.ProtectedError
Raised to prevent deletion of referenced objects when using

View File

@ -60,6 +60,8 @@ Minor features
* In addition to :lookup:`year`, :lookup:`month` and :lookup:`day`, the ORM
now supports :lookup:`hour`, :lookup:`minute` and :lookup:`second` lookups.
* Django now wraps all PEP-249 exceptions.
* The default widgets for :class:`~django.forms.EmailField`,
:class:`~django.forms.URLField`, :class:`~django.forms.IntegerField`,
:class:`~django.forms.FloatField` and :class:`~django.forms.DecimalField` use