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from django.db import connection, DatabaseError
from django.core.exceptions import ImproperlyConfigured
import django.core.management
import logging
import re
import sys
import traceback
from Bcfg2.Compat import CmpMixin, walk_packages
from Bcfg2.Server.models import InternalDatabaseVersion
from Bcfg2.Server.SchemaUpdater.Routines import UpdaterRoutineException, \
UpdaterRoutine
from Bcfg2.Server.SchemaUpdater import Changes
logger = logging.getLogger(__name__)
class UpdaterError(Exception):
pass
class SchemaTooOldError(UpdaterError):
pass
def _release_to_version(release):
"""
Build a release base for a version
Expects a string of the form 00.00
returns an integer of the form MMmm00
"""
regex = re.compile("^(\d+)\.(\d+)$")
m = regex.match(release)
if not m:
logger.error("Invalid release string: %s" % release)
raise TypeError
return int("%02d%02d00" % (int(m.group(1)), int(m.group(2))))
class Updater(CmpMixin):
"""Database updater to standardize updates"""
def __init__(self, release):
CmpMixin.__init__(self)
self._cursor = None
self._release = release
try:
self._base_version = _release_to_version(release)
except:
err = "Invalid release string: %s" % release
logger.error(err)
raise UpdaterError(err)
self._fixes = []
self._version = -1
def __cmp__(self, other):
return self._base_version - other._base_version
@property
def release(self):
return self._release
@property
def version(self):
if self._version < 0:
try:
iv = InternalDatabaseVersion.objects.latest()
self._version = iv.version
except InternalDatabaseVersion.DoesNotExist:
raise UpdaterError("No database version stored internally")
return self._version
@property
def cursor(self):
if not self._cursor:
self._cursor = connection.cursor()
return self._cursor
@property
def target_version(self):
if(len(self._fixes) == 0):
return self._base_version
else:
return self._base_version + len(self._fixes) - 1
def add(self, update):
if type(update) == str or isinstance(update, UpdaterRoutine):
self._fixes.append(update)
else:
raise TypeError
def override_base_version(self, version):
"""Override our starting point for old releases. New code should
not use this method"""
self._base_version = int(version)
@staticmethod
def get_current_version():
"""Queries the db for the latest version. Returns 0 for a
fresh install"""
if "call_command" in dir(django.core.management):
django.core.management.call_command("syncdb", interactive=False,
verbosity=0)
else:
msg = "Unable to call syndb routine"
logger.warning(msg)
raise UpdaterError(msg)
try:
iv = InternalDatabaseVersion.objects.latest()
version = iv.version
except InternalDatabaseVersion.DoesNotExist:
version = 0
return version
def syncdb(self):
"""Function to do the syncronisation for the models"""
self._version = Updater.get_current_version()
self._cursor = None
def increment(self):
"""Increment schema version in the database"""
if self._version < self._base_version:
self._version = self._base_version
else:
self._version += 1
InternalDatabaseVersion.objects.create(version=self._version)
def apply(self):
"""Apply pending schema changes"""
if self.version >= self.target_version:
logger.debug("No updates for release %s" % self._release)
return
logger.debug("Applying updates for release %s" % self._release)
if self.version < self._base_version:
start = 0
else:
start = self.version - self._base_version + 1
try:
for fix in self._fixes[start:]:
if type(fix) == str:
self.cursor.execute(fix)
elif isinstance(fix, UpdaterRoutine):
fix.run()
else:
logger.error("Invalid schema change at %s" % \
self._version + 1)
self.increment()
logger.debug("Applied schema change number %s: %s" % \
(self.version, fix))
logger.info("Applied schema changes for release %s" % self._release)
except:
msg = "Failed to perform db update %s (%s): %s" % \
(self._version + 1, fix,
traceback.format_exc().splitlines()[-1])
logger.error(msg)
raise UpdaterError(msg)
class UnsupportedUpdate(Updater):
"""Handle an unsupported update"""
def __init__(self, release, version):
super(UnsupportedUpdate, self).__init__(release)
self._base_version = version
def apply(self):
"""Raise an exception if we're too old"""
if self.version < self.target_version:
logger.error("Upgrade from release %s unsupported" % self._release)
raise SchemaTooOldError
def update_database():
"""method to search where we are in the revision
of the database models and update them"""
try:
logger.debug("Verifying database schema")
updaters = []
for loader, submodule, ispkg in walk_packages(path=Changes.__path__):
if ispkg:
continue
try:
updates = getattr(
__import__("%s.%s" % (Changes.__name__, submodule),
globals(), locals(), ['*']),
"updates")
updaters.append(updates())
except ImportError:
logger.error("Failed to import %s" % submodule)
except AttributeError:
logger.warning("Module %s does not have an updates function" %
submodule)
except:
msg = "Failed to build updater for %s" % submodule
logger.error(msg, exc_info=1)
raise UpdaterError(msg)
current_version = Updater.get_current_version()
logger.debug("Database version at %s" % current_version)
updaters.sort()
if current_version > 0:
[u.apply() for u in updaters]
logger.debug("Database version at %s" %
Updater.get_current_version())
else:
target = updaters[-1].target_version
InternalDatabaseVersion.objects.create(version=target)
logger.info("A new database was created")
except UpdaterError:
raise
except ImproperlyConfigured:
logger.error("Django is not properly configured: %s" %
traceback.format_exc().splitlines()[-1])
raise UpdaterError
except:
logger.error("Error while updating the database")
for x in traceback.format_exc().splitlines():
logger.error(x)
raise UpdaterError
|
