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Viewing changes to lib/canonical/database/sqlbase.py

  • Committer: Jelmer Vernooij
  • Date: 2011-09-21 14:28:02 UTC
  • mfrom: (14006 devel)
  • mto: This revision was merged to the branch mainline in revision 14010.
  • Revision ID: jelmer@canonical.com-20110921142802-7ggkc204igsy532w
Merge lp:launchpad

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lib/canonical/database/sqlbase.py
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__metaclass__ = type
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__all__ = [
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    'alreadyInstalledMsg',
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    'begin',
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    'block_implicit_flushes',
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    'clear_current_connection_cache',
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    'commit',
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    'ConflictingTransactionManagerError',
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    'connect',
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    'convert_storm_clause_to_string',
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    'cursor',
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    'expire_from_cache',
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    'flush_database_caches',
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    'flush_database_updates',
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    'get_transaction_timestamp',
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    'quoteIdentifier',
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    'quote_identifier',
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    'reset_store',
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    'rollback',
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    'session_store',
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    'SQLBase',
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    'sqlvalues',
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from datetime import datetime
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from textwrap import dedent
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import warnings
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from lazr.restful.interfaces import IRepresentationCache
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import psycopg2
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from zope.interface import implements
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from zope.security.proxy import removeSecurityProxy
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from canonical.config import (
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    config,
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    dbconfig,
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    )
 
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from canonical.config import dbconfig
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from canonical.database.interfaces import ISQLBase
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from lp.services.propertycache import clear_property_cache
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        clear_property_cache(self)
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alreadyInstalledMsg = ("A ZopelessTransactionManager with these settings is "
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"already installed.  This is probably caused by calling initZopeless twice.")
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class ConflictingTransactionManagerError(Exception):
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    pass
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class ZopelessTransactionManager(object):
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    """Compatibility shim for initZopeless()"""
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    _installed = None
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    _CONFIG_OVERLAY_NAME = 'initZopeless config overlay'
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    def __init__(self):
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        raise AssertionError("ZopelessTransactionManager should not be "
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            ISOLATION_LEVEL_READ_COMMITTED: 'read_committed',
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            ISOLATION_LEVEL_SERIALIZABLE: 'serializable'}[isolation]
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        # Construct a config fragment:
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        overlay = dedent("""\
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            [database]
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            isolation_level: %(isolation_level)s
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            [launchpad]
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            dbuser: %(dbuser)s
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            """ % dict(
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                isolation_level=isolation_level,
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                dbuser=dbuser))
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        if cls._installed is not None:
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            if cls._config_overlay != overlay:
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                raise ConflictingTransactionManagerError(
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                        "A ZopelessTransactionManager with different "
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                        "settings is already installed")
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            # There's an identical ZopelessTransactionManager already
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            # installed, so return that one, but also emit a warning.
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            warnings.warn(alreadyInstalledMsg, stacklevel=3)
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        else:
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            config.push(cls._CONFIG_OVERLAY_NAME, overlay)
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            cls._config_overlay = overlay
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            cls._dbuser = dbuser
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            cls._isolation = isolation
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            cls._reset_stores()
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            cls._installed = cls
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        return cls._installed
 
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        dbconfig.override(dbuser=dbuser, isolation_level=isolation_level)
 
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        cls._dbuser = dbuser
 
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        cls._isolation = isolation
 
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        cls._reset_stores()
 
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        cls._installed = cls
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    @staticmethod
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    def _reset_stores():
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        """
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        assert cls._installed is not None, (
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            "ZopelessTransactionManager not installed")
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        config.pop(cls._CONFIG_OVERLAY_NAME)
 
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        dbconfig.override(dbuser=None, isolation_level=None)
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        cls._reset_stores()
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        cls._installed = None
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    @classmethod
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    def set_isolation_level(cls, isolation):
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        """Set the transaction isolation level.
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        Level can be one of ISOLATION_LEVEL_AUTOCOMMIT,
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        ISOLATION_LEVEL_READ_COMMITTED or
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        ISOLATION_LEVEL_SERIALIZABLE. As changing the isolation level
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        must be done before any other queries are issued in the
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        current transaction, this method automatically issues a
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        rollback to ensure this is the case.
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        """
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        assert cls._installed is not None, (
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            "ZopelessTransactionManager not installed")
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        cls.uninstall()
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        cls.initZopeless(cls._dbuser, isolation)
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    @staticmethod
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    def conn():
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        store = _get_sqlobject_store()
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        # Use of the raw connection will not be coherent with Storm's
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        # cache.
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        connection = store._connection
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        connection._ensure_connected()
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        return connection._raw_connection
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    @staticmethod
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    def begin():
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        """Begin a transaction."""
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        transaction.begin()
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    @staticmethod
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    def commit():
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        """Commit the current transaction."""
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        transaction.commit()
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    @staticmethod
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    def abort():
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        """Abort the current transaction."""
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        transaction.abort()
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    @staticmethod
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    def registerSynch(synch):
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        """Register an ISynchronizer."""
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        transaction.manager.registerSynch(synch)
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    @staticmethod
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    def unregisterSynch(synch):
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        """Unregister an ISynchronizer."""
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        transaction.manager.unregisterSynch(synch)
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def clear_current_connection_cache():
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    """Clear SQLObject's object cache. SQLObject compatibility - DEPRECATED.
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    _get_sqlobject_store().invalidate()
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def expire_from_cache(obj):
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    """Expires a single object from the SQLObject cache.
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    SQLObject compatibility - DEPRECATED."""
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    _get_sqlobject_store().invalidate(obj)
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def get_transaction_timestamp():
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    """Get the timestamp for the current transaction on the MAIN DEFAULT
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    store. DEPRECATED - if needed it should become a method on the store.
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    return mergeFunctionMetadata(func, reset_store_decorator)
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# Some helpers intended for use with initZopeless.  These allow you to avoid
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# passing the transaction manager all through your code.
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def begin():
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    """Begins a transaction."""
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    transaction.begin()
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def rollback():
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    transaction.abort()
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# DEPRECATED -- use transaction.commit() directly.
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def commit():
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    transaction.commit()
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