class MigrationPackage(object):
"""
A wrapper around the migration packages found in pulp.server.db.migrations. Has methods to
retrieve information about the migrations that are found there, and to apply the migrations.
"""
class DuplicateVersions(Exception):
"""
This is raised when a single migration package has two MigrationModules in it that have the
same version.
"""
pass
class MissingVersion(Exception):
"""
This is raised when a migration package has a gap in the MigrationModule versions.
"""
pass
def __init__(self, python_package):
"""
Initialize the MigrationPackage to represent the Python migration package passed in.
:param python_package: The Python package this object should represent
:type python_package: package
"""
self._package = python_package
# This is an object representation of the DB object that keeps track of the migration
# version that has been applied
try:
self._migration_tracker = MigrationTracker.objects().get(name=self.name)
except DoesNotExist:
self._migration_tracker = MigrationTracker(name=self.name)
self._migration_tracker.save()
# Calculate the latest available version
available_versions = self.available_versions
if available_versions:
self.latest_available_version = available_versions[-1]
else:
self.latest_available_version = 0
def apply_migration(self, migration, update_current_version=True):
"""
Apply the migration that is passed in, and update the DB to note the new version that this
migration represents.
:param migration: The migration to apply
:type migration: pulp.server.db.migrate.utils.MigrationModule
:param update_current_version: If True, update the package's current version after
successful application and enforce migration version order.
If False, don't enforce and don't update.
:type update_current_version: bool
"""
if update_current_version and migration.version != self.current_version + 1:
msg = _('Cannot apply migration %(name)s, because the next migration version is '
'%(version)s.')
msg = msg % {'name': migration.name, 'version': self.current_version + 1}
raise Exception(msg)
migration.migrate()
if update_current_version:
self._migration_tracker.version = migration.version
self._migration_tracker.save()
@property
def available_versions(self):
"""
Return a list of the migration versions that are available in this migration package.
:rtype: list
"""
migrations = self.migrations
versions = [migration.version for migration in migrations]
return versions
@property
def current_version(self):
"""
An integer that represents the migration version that the database is currently at.
None means that the migration package has never been run before.
:rtype: int
"""
return self._migration_tracker.version
@property
def migrations(self):
"""
Finds all available migration modules for the MigrationPackage,
and then sorts by the version. Return a list of MigrationModules.
:rtype: list
"""
# Generate a list of the names of the modules found inside this package
module_names = [name for module_loader, name, ispkg in
iter_modules([os.path.dirname(self._package.__file__)])]
migration_modules = []
for module_name in module_names:
try:
module_name = '%s.%s' % (self.name, module_name)
migration_modules.append(MigrationModule(module_name))
except MigrationModule.MissingMigrate:
msg = _("The module %(m)s doesn't have a migrate function. It will be ignored.")
msg = msg % {'m': module_name}
_logger.debug(msg)
except MigrationModule.MissingVersion:
msg = _("The module %(m)s doesn't conform to the migration package naming "
"conventions. It will be ignored.")
msg = msg % {'m': module_name}
_logger.debug(msg)
migration_modules.sort()
# We should have migrations starting at version 1, which each module version being exactly
# one larger than the migration preceeding it.
last_version = 0
for module in migration_modules:
if module.version == 0:
error_message = _('0 is a reserved migration version number, but the '
'module %(n)s has been assigned that version.')
error_message = error_message % {'n': module.name}
raise self.__class__.DuplicateVersions(error_message)
if module.version == last_version:
error_message = _('There are two migration modules that share version %(v)s in '
'%(n)s.')
error_message = error_message % {'v': module.version, 'n': self.name}
raise self.__class__.DuplicateVersions(error_message)
if module.version != last_version + 1:
msg = _('Migration version %(v)s is missing in %(n)s.')
msg = msg % ({'v': last_version + 1, 'n': self.name})
raise self.__class__.MissingVersion(msg)
last_version = module.version
return migration_modules
@property
def name(self):
"""
Returns the name of the Python package that this MigrationPackage represents.
:rtype: str
"""
return self._package.__name__
@property
def unapplied_migrations(self):
"""
Return a list of MigrationModules in this package that have not been applied yet.
:rtype: list
"""
return [migration for migration in self.migrations
if migration.version > self.current_version]
def __cmp__(self, other_package):
"""
This method returns a negative value if self.name < other_package.name, 0 if they are
equal, and a positive value if self.name > other_package.name. There is an exception to this
sorting rule, in that if self._package is pulp.server.db.migrations, this method will always
return -1, and if other_package is pulp.server.db.migrations, it will always return 1.
:rtype: int
"""
if self._package is pulp.server.db.migrations:
return -1
if other_package._package is pulp.server.db.migrations:
return 1
return cmp(self.name, other_package.name)
def __str__(self):
return self.name
def __repr__(self):
return str(self)
class MigrationPackage(object):
"""
A wrapper around the migration packages found in pulp.server.db.migrations. Has methods to
retrieve information about the migrations that are found there, and to apply the migrations.
"""
class DuplicateVersions(Exception):
"""
This is raised when a single migration package has two MigrationModules in it that have the
same version.
"""
pass
class MissingVersion(Exception):
"""
This is raised when a migration package has a gap in the MigrationModule versions.
"""
pass
def __init__(self, python_package):
"""
Initialize the MigrationPackage to represent the Python migration package passed in.
:param python_package: The Python package this object should represent
:type python_package: package
"""
self._package = python_package
# This is an object representation of the DB object that keeps track of the migration
# version that has been applied
try:
self._migration_tracker = MigrationTracker.objects().get(name=self.name)
except DoesNotExist:
self._migration_tracker = MigrationTracker(name=self.name)
self._migration_tracker.save()
# Calculate the latest available version
available_versions = self.available_versions
if available_versions:
self.latest_available_version = available_versions[-1]
else:
self.latest_available_version = 0
def apply_migration(self, migration, update_current_version=True):
"""
Apply the migration that is passed in, and update the DB to note the new version that this
migration represents.
:param migration: The migration to apply
:type migration: pulp.server.db.migrate.utils.MigrationModule
:param update_current_version: If True, update the package's current version after
successful application and enforce migration version order.
If False, don't enforce and don't update.
:type update_current_version: bool
"""
if update_current_version and migration.version != self.current_version + 1:
msg = _("Cannot apply migration %(name)s, because the next migration version is " "%(version)s.")
msg = msg % {"name": migration.name, "version": self.current_version + 1}
raise Exception(msg)
migration.migrate()
if update_current_version:
self._migration_tracker.version = migration.version
self._migration_tracker.save()
@property
def available_versions(self):
"""
Return a list of the migration versions that are available in this migration package.
:rtype: list
"""
migrations = self.migrations
versions = [migration.version for migration in migrations]
return versions
@property
def current_version(self):
"""
An integer that represents the migration version that the database is currently at.
None means that the migration package has never been run before.
:rtype: int
"""
return self._migration_tracker.version
@property
def migrations(self):
"""
Finds all available migration modules for the MigrationPackage,
and then sorts by the version. Return a list of MigrationModules.
:rtype: list
"""
# Generate a list of the names of the modules found inside this package
module_names = [name for module_loader, name, ispkg in iter_modules([os.path.dirname(self._package.__file__)])]
migration_modules = []
for module_name in module_names:
try:
module_name = "%s.%s" % (self.name, module_name)
migration_modules.append(MigrationModule(module_name))
except MigrationModule.MissingMigrate:
msg = _("The module %(m)s doesn't have a migrate function. It will be ignored.")
msg = msg % {"m": module_name}
_logger.debug(msg)
except MigrationModule.MissingVersion:
msg = _(
"The module %(m)s doesn't conform to the migration package naming "
"conventions. It will be ignored."
)
msg = msg % {"m": module_name}
_logger.debug(msg)
migration_modules.sort()
# We should have migrations starting at version 1, which each module version being exactly
# one larger than the migration preceeding it.
last_version = 0
for module in migration_modules:
if module.version == 0:
error_message = _(
"0 is a reserved migration version number, but the " "module %(n)s has been assigned that version."
)
error_message = error_message % {"n": module.name}
raise self.__class__.DuplicateVersions(error_message)
if module.version == last_version:
error_message = _("There are two migration modules that share version %(v)s in " "%(n)s.")
error_message = error_message % {"v": module.version, "n": self.name}
raise self.__class__.DuplicateVersions(error_message)
if module.version != last_version + 1:
msg = _("Migration version %(v)s is missing in %(n)s.")
msg = msg % ({"v": last_version + 1, "n": self.name})
raise self.__class__.MissingVersion(msg)
last_version = module.version
return migration_modules
@property
def name(self):
"""
Returns the name of the Python package that this MigrationPackage represents.
:rtype: str
"""
return self._package.__name__
@property
def unapplied_migrations(self):
"""
Return a list of MigrationModules in this package that have not been applied yet.
:rtype: list
"""
return [migration for migration in self.migrations if migration.version > self.current_version]
def __cmp__(self, other_package):
"""
This method returns a negative value if self.name < other_package.name, 0 if they are
equal, and a positive value if self.name > other_package.name. There is an exception to this
sorting rule, in that if self._package is pulp.server.db.migrations, this method will always
return -1, and if other_package is pulp.server.db.migrations, it will always return 1.
:rtype: int
"""
if self._package is pulp.server.db.migrations:
return -1
if other_package._package is pulp.server.db.migrations:
return 1
return cmp(self.name, other_package.name)
def __str__(self):
return self.name
def __repr__(self):
return str(self)
