py3: remove usage of basestring
py3: remove usage of basestring

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schema.py
666 lines | 22.6 KiB | text/x-python | PythonLexer
"""
Schema module providing common schema operations.
"""
import warnings
from UserDict import DictMixin
import sqlalchemy
from sqlalchemy.schema import ForeignKeyConstraint
from sqlalchemy.schema import UniqueConstraint
from pyramid import compat
from rhodecode.lib.dbmigrate.migrate.exceptions import *
from rhodecode.lib.dbmigrate.migrate.changeset import SQLA_07, SQLA_08
from rhodecode.lib.dbmigrate.migrate.changeset import util
from rhodecode.lib.dbmigrate.migrate.changeset.databases.visitor import (
get_engine_visitor, run_single_visitor)
__all__ = [
'create_column',
'drop_column',
'alter_column',
'rename_table',
'rename_index',
'ChangesetTable',
'ChangesetColumn',
'ChangesetIndex',
'ChangesetDefaultClause',
'ColumnDelta',
]
def create_column(column, table=None, *p, **kw):
"""Create a column, given the table.
API to :meth:`ChangesetColumn.create`.
"""
if table is not None:
return table.create_column(column, *p, **kw)
return column.create(*p, **kw)
def drop_column(column, table=None, *p, **kw):
"""Drop a column, given the table.
API to :meth:`ChangesetColumn.drop`.
"""
if table is not None:
return table.drop_column(column, *p, **kw)
return column.drop(*p, **kw)
def rename_table(table, name, engine=None, **kw):
"""Rename a table.
If Table instance is given, engine is not used.
API to :meth:`ChangesetTable.rename`.
:param table: Table to be renamed.
:param name: New name for Table.
:param engine: Engine instance.
:type table: string or Table instance
:type name: string
:type engine: obj
"""
table = _to_table(table, engine)
table.rename(name, **kw)
def rename_index(index, name, table=None, engine=None, **kw):
"""Rename an index.
If Index instance is given,
table and engine are not used.
API to :meth:`ChangesetIndex.rename`.
:param index: Index to be renamed.
:param name: New name for index.
:param table: Table to which Index is reffered.
:param engine: Engine instance.
:type index: string or Index instance
:type name: string
:type table: string or Table instance
:type engine: obj
"""
index = _to_index(index, table, engine)
index.rename(name, **kw)
def alter_column(*p, **k):
"""Alter a column.
This is a helper function that creates a :class:`ColumnDelta` and
runs it.
:argument column:
The name of the column to be altered or a
:class:`ChangesetColumn` column representing it.
:param table:
A :class:`~sqlalchemy.schema.Table` or table name to
for the table where the column will be changed.
:param engine:
The :class:`~sqlalchemy.engine.base.Engine` to use for table
reflection and schema alterations.
:returns: A :class:`ColumnDelta` instance representing the change.
"""
if 'table' not in k and isinstance(p[0], sqlalchemy.Column):
k['table'] = p[0].table
if 'engine' not in k:
k['engine'] = k['table'].bind
# deprecation
if len(p) >= 2 and isinstance(p[1], sqlalchemy.Column):
warnings.warn(
"Passing a Column object to alter_column is deprecated."
" Just pass in keyword parameters instead.",
MigrateDeprecationWarning
)
engine = k['engine']
# enough tests seem to break when metadata is always altered
# that this crutch has to be left in until they can be sorted
# out
k['alter_metadata']=True
delta = ColumnDelta(*p, **k)
visitorcallable = get_engine_visitor(engine, 'schemachanger')
engine._run_visitor(visitorcallable, delta)
return delta
def _to_table(table, engine=None):
"""Return if instance of Table, else construct new with metadata"""
if isinstance(table, sqlalchemy.Table):
return table
# Given: table name, maybe an engine
meta = sqlalchemy.MetaData()
if engine is not None:
meta.bind = engine
return sqlalchemy.Table(table, meta)
def _to_index(index, table=None, engine=None):
"""Return if instance of Index, else construct new with metadata"""
if isinstance(index, sqlalchemy.Index):
return index
# Given: index name; table name required
table = _to_table(table, engine)
ret = sqlalchemy.Index(index)
ret.table = table
return ret
class ColumnDelta(DictMixin, sqlalchemy.schema.SchemaItem):
"""Extracts the differences between two columns/column-parameters
May receive parameters arranged in several different ways:
* **current_column, new_column, \*p, \*\*kw**
Additional parameters can be specified to override column
differences.
* **current_column, \*p, \*\*kw**
Additional parameters alter current_column. Table name is extracted
from current_column object.
Name is changed to current_column.name from current_name,
if current_name is specified.
* **current_col_name, \*p, \*\*kw**
Table kw must specified.
:param table: Table at which current Column should be bound to.\
If table name is given, reflection will be used.
:type table: string or Table instance
:param metadata: A :class:`MetaData` instance to store
reflected table names
:param engine: When reflecting tables, either engine or metadata must \
be specified to acquire engine object.
:type engine: :class:`Engine` instance
:returns: :class:`ColumnDelta` instance provides interface for altered attributes to \
`result_column` through :func:`dict` alike object.
* :class:`ColumnDelta`.result_column is altered column with new attributes
* :class:`ColumnDelta`.current_name is current name of column in db
"""
# Column attributes that can be altered
diff_keys = ('name', 'type', 'primary_key', 'nullable',
'server_onupdate', 'server_default', 'autoincrement')
diffs = dict()
__visit_name__ = 'column'
def __init__(self, *p, **kw):
# 'alter_metadata' is not a public api. It exists purely
# as a crutch until the tests that fail when 'alter_metadata'
# behaviour always happens can be sorted out
self.alter_metadata = kw.pop("alter_metadata", False)
self.meta = kw.pop("metadata", None)
self.engine = kw.pop("engine", None)
# Things are initialized differently depending on how many column
# parameters are given. Figure out how many and call the appropriate
# method.
if len(p) >= 1 and isinstance(p[0], sqlalchemy.Column):
# At least one column specified
if len(p) >= 2 and isinstance(p[1], sqlalchemy.Column):
# Two columns specified
diffs = self.compare_2_columns(*p, **kw)
else:
# Exactly one column specified
diffs = self.compare_1_column(*p, **kw)
else:
# Zero columns specified
if not len(p) or not isinstance(p[0], compat.string_types):
raise ValueError("First argument must be column name")
diffs = self.compare_parameters(*p, **kw)
self.apply_diffs(diffs)
def __repr__(self):
return '<ColumnDelta altermetadata=%r, %s>' % (
self.alter_metadata,
super(ColumnDelta, self).__repr__()
)
def __getitem__(self, key):
if key not in self.keys():
raise KeyError("No such diff key, available: %s" % self.diffs )
return getattr(self.result_column, key)
def __setitem__(self, key, value):
if key not in self.keys():
raise KeyError("No such diff key, available: %s" % self.diffs )
setattr(self.result_column, key, value)
def __delitem__(self, key):
raise NotImplementedError
def __len__(self):
raise NotImplementedError
def __iter__(self):
raise NotImplementedError
def keys(self):
return self.diffs.keys()
def compare_parameters(self, current_name, *p, **k):
"""Compares Column objects with reflection"""
self.table = k.pop('table')
self.result_column = self._table.c.get(current_name)
if len(p):
k = self._extract_parameters(p, k, self.result_column)
return k
def compare_1_column(self, col, *p, **k):
"""Compares one Column object"""
self.table = k.pop('table', None)
if self.table is None:
self.table = col.table
self.result_column = col
if len(p):
k = self._extract_parameters(p, k, self.result_column)
return k
def compare_2_columns(self, old_col, new_col, *p, **k):
"""Compares two Column objects"""
self.process_column(new_col)
self.table = k.pop('table', None)
# we cannot use bool() on table in SA06
if self.table is None:
self.table = old_col.table
if self.table is None:
new_col.table
self.result_column = old_col
# set differences
# leave out some stuff for later comp
for key in (set(self.diff_keys) - set(('type',))):
val = getattr(new_col, key, None)
if getattr(self.result_column, key, None) != val:
k.setdefault(key, val)
# inspect types
if not self.are_column_types_eq(self.result_column.type, new_col.type):
k.setdefault('type', new_col.type)
if len(p):
k = self._extract_parameters(p, k, self.result_column)
return k
def apply_diffs(self, diffs):
"""Populate dict and column object with new values"""
self.diffs = diffs
for key in self.diff_keys:
if key in diffs:
setattr(self.result_column, key, diffs[key])
self.process_column(self.result_column)
# create an instance of class type if not yet
if 'type' in diffs and callable(self.result_column.type):
self.result_column.type = self.result_column.type()
# add column to the table
if self.table is not None and self.alter_metadata:
self.result_column.add_to_table(self.table)
def are_column_types_eq(self, old_type, new_type):
"""Compares two types to be equal"""
ret = old_type.__class__ == new_type.__class__
# String length is a special case
if ret and isinstance(new_type, sqlalchemy.types.String):
ret = (getattr(old_type, 'length', None) == \
getattr(new_type, 'length', None))
return ret
def _extract_parameters(self, p, k, column):
"""Extracts data from p and modifies diffs"""
p = list(p)
while len(p):
if isinstance(p[0], compat.string_types):
k.setdefault('name', p.pop(0))
elif isinstance(p[0], sqlalchemy.types.TypeEngine):
k.setdefault('type', p.pop(0))
elif callable(p[0]):
p[0] = p[0]()
else:
break
if len(p):
new_col = column.copy_fixed()
new_col._init_items(*p)
k = self.compare_2_columns(column, new_col, **k)
return k
def process_column(self, column):
"""Processes default values for column"""
# XXX: this is a snippet from SA processing of positional parameters
toinit = list()
if column.server_default is not None:
if isinstance(column.server_default, sqlalchemy.FetchedValue):
toinit.append(column.server_default)
else:
toinit.append(sqlalchemy.DefaultClause(column.server_default))
if column.server_onupdate is not None:
if isinstance(column.server_onupdate, FetchedValue):
toinit.append(column.server_default)
else:
toinit.append(sqlalchemy.DefaultClause(column.server_onupdate,
for_update=True))
if toinit:
column._init_items(*toinit)
def _get_table(self):
return getattr(self, '_table', None)
def _set_table(self, table):
if isinstance(table, compat.string_types):
if self.alter_metadata:
if not self.meta:
raise ValueError("metadata must be specified for table"
" reflection when using alter_metadata")
meta = self.meta
if self.engine:
meta.bind = self.engine
else:
if not self.engine and not self.meta:
raise ValueError("engine or metadata must be specified"
" to reflect tables")
if not self.engine:
self.engine = self.meta.bind
meta = sqlalchemy.MetaData(bind=self.engine)
self._table = sqlalchemy.Table(table, meta, autoload=True)
elif isinstance(table, sqlalchemy.Table):
self._table = table
if not self.alter_metadata:
self._table.meta = sqlalchemy.MetaData(bind=self._table.bind)
def _get_result_column(self):
return getattr(self, '_result_column', None)
def _set_result_column(self, column):
"""Set Column to Table based on alter_metadata evaluation."""
self.process_column(column)
if not hasattr(self, 'current_name'):
self.current_name = column.name
if self.alter_metadata:
self._result_column = column
else:
self._result_column = column.copy_fixed()
table = property(_get_table, _set_table)
result_column = property(_get_result_column, _set_result_column)
class ChangesetTable(object):
"""Changeset extensions to SQLAlchemy tables."""
def create_column(self, column, *p, **kw):
"""Creates a column.
The column parameter may be a column definition or the name of
a column in this table.
API to :meth:`ChangesetColumn.create`
:param column: Column to be created
:type column: Column instance or string
"""
if not isinstance(column, sqlalchemy.Column):
# It's a column name
column = getattr(self.c, str(column))
column.create(table=self, *p, **kw)
def drop_column(self, column, *p, **kw):
"""Drop a column, given its name or definition.
API to :meth:`ChangesetColumn.drop`
:param column: Column to be droped
:type column: Column instance or string
"""
if not isinstance(column, sqlalchemy.Column):
# It's a column name
try:
column = getattr(self.c, str(column))
except AttributeError:
# That column isn't part of the table. We don't need
# its entire definition to drop the column, just its
# name, so create a dummy column with the same name.
column = sqlalchemy.Column(str(column), sqlalchemy.Integer())
column.drop(table=self, *p, **kw)
def rename(self, name, connection=None, **kwargs):
"""Rename this table.
:param name: New name of the table.
:type name: string
:param connection: reuse connection istead of creating new one.
:type connection: :class:`sqlalchemy.engine.base.Connection` instance
"""
engine = self.bind
self.new_name = name
visitorcallable = get_engine_visitor(engine, 'schemachanger')
run_single_visitor(engine, visitorcallable, self, connection, **kwargs)
# Fix metadata registration
self.name = name
self.deregister()
self._set_parent(self.metadata)
def _meta_key(self):
"""Get the meta key for this table."""
return sqlalchemy.schema._get_table_key(self.name, self.schema)
def deregister(self):
"""Remove this table from its metadata"""
if SQLA_07:
self.metadata._remove_table(self.name, self.schema)
else:
key = self._meta_key()
meta = self.metadata
if key in meta.tables:
del meta.tables[key]
class ChangesetColumn(object):
"""Changeset extensions to SQLAlchemy columns."""
def alter(self, *p, **k):
"""Makes a call to :func:`alter_column` for the column this
method is called on.
"""
if 'table' not in k:
k['table'] = self.table
if 'engine' not in k:
k['engine'] = k['table'].bind
return alter_column(self, *p, **k)
def create(self, table=None, index_name=None, unique_name=None,
primary_key_name=None, populate_default=True, connection=None, **kwargs):
"""Create this column in the database.
Assumes the given table exists. ``ALTER TABLE ADD COLUMN``,
for most databases.
:param table: Table instance to create on.
:param index_name: Creates :class:`ChangesetIndex` on this column.
:param unique_name: Creates :class:\
`~migrate.changeset.constraint.UniqueConstraint` on this column.
:param primary_key_name: Creates :class:\
`~migrate.changeset.constraint.PrimaryKeyConstraint` on this column.
:param populate_default: If True, created column will be \
populated with defaults
:param connection: reuse connection istead of creating new one.
:type table: Table instance
:type index_name: string
:type unique_name: string
:type primary_key_name: string
:type populate_default: bool
:type connection: :class:`sqlalchemy.engine.base.Connection` instance
:returns: self
"""
self.populate_default = populate_default
self.index_name = index_name
self.unique_name = unique_name
self.primary_key_name = primary_key_name
for cons in ('index_name', 'unique_name', 'primary_key_name'):
self._check_sanity_constraints(cons)
self.add_to_table(table)
engine = self.table.bind
visitorcallable = get_engine_visitor(engine, 'columngenerator')
engine._run_visitor(visitorcallable, self, connection, **kwargs)
# TODO: reuse existing connection
if self.populate_default and self.default is not None:
stmt = table.update().values({self: engine._execute_default(self.default)})
engine.execute(stmt)
return self
def drop(self, table=None, connection=None, **kwargs):
"""Drop this column from the database, leaving its table intact.
``ALTER TABLE DROP COLUMN``, for most databases.
:param connection: reuse connection istead of creating new one.
:type connection: :class:`sqlalchemy.engine.base.Connection` instance
"""
if table is not None:
self.table = table
engine = self.table.bind
visitorcallable = get_engine_visitor(engine, 'columndropper')
engine._run_visitor(visitorcallable, self, connection, **kwargs)
self.remove_from_table(self.table, unset_table=False)
self.table = None
return self
def add_to_table(self, table):
if table is not None and self.table is None:
if SQLA_07:
table.append_column(self)
else:
self._set_parent(table)
def _col_name_in_constraint(self,cons,name):
return False
def remove_from_table(self, table, unset_table=True):
# TODO: remove primary keys, constraints, etc
if unset_table:
self.table = None
to_drop = set()
for index in table.indexes:
columns = []
for col in index.columns:
if col.name!=self.name:
columns.append(col)
if columns:
index.columns = columns
if SQLA_08:
index.expressions = columns
else:
to_drop.add(index)
table.indexes = table.indexes - to_drop
to_drop = set()
for cons in table.constraints:
# TODO: deal with other types of constraint
if isinstance(cons,(ForeignKeyConstraint,
UniqueConstraint)):
for col_name in cons.columns:
if not isinstance(col_name, compat.string_types):
col_name = col_name.name
if self.name==col_name:
to_drop.add(cons)
table.constraints = table.constraints - to_drop
if table.c.contains_column(self):
if SQLA_07:
table._columns.remove(self)
else:
table.c.remove(self)
# TODO: this is fixed in 0.6
def copy_fixed(self, **kw):
"""Create a copy of this ``Column``, with all attributes."""
q = util.safe_quote(self)
return sqlalchemy.Column(self.name, self.type, self.default,
key=self.key,
primary_key=self.primary_key,
nullable=self.nullable,
quote=q,
index=self.index,
unique=self.unique,
onupdate=self.onupdate,
autoincrement=self.autoincrement,
server_default=self.server_default,
server_onupdate=self.server_onupdate,
*[c.copy(**kw) for c in self.constraints])
def _check_sanity_constraints(self, name):
"""Check if constraints names are correct"""
obj = getattr(self, name)
if (getattr(self, name[:-5]) and not obj):
raise InvalidConstraintError("Column.create() accepts index_name,"
" primary_key_name and unique_name to generate constraints")
if not isinstance(obj, compat.string_types) and obj is not None:
raise InvalidConstraintError(
"%s argument for column must be constraint name" % name)
class ChangesetIndex(object):
"""Changeset extensions to SQLAlchemy Indexes."""
__visit_name__ = 'index'
def rename(self, name, connection=None, **kwargs):
"""Change the name of an index.
:param name: New name of the Index.
:type name: string
:param connection: reuse connection istead of creating new one.
:type connection: :class:`sqlalchemy.engine.base.Connection` instance
"""
engine = self.table.bind
self.new_name = name
visitorcallable = get_engine_visitor(engine, 'schemachanger')
engine._run_visitor(visitorcallable, self, connection, **kwargs)
self.name = name
class ChangesetDefaultClause(object):
"""Implements comparison between :class:`DefaultClause` instances"""
def __eq__(self, other):
if isinstance(other, self.__class__):
if self.arg == other.arg:
return True
def __ne__(self, other):
return not self.__eq__(other)