Current File : //opt/alt/python37/lib/python3.7/site-packages/alembic/autogenerate/compare.py
from sqlalchemy import schema as sa_schema, types as sqltypes
from sqlalchemy.engine.reflection import Inspector
from sqlalchemy import event
from ..operations import ops
import logging
from .. import util
from ..util import compat
from ..util import sqla_compat
from sqlalchemy.util import OrderedSet
import re
from .render import _user_defined_render
import contextlib
from alembic.ddl.base import _fk_spec
log = logging.getLogger(__name__)
def _populate_migration_script(autogen_context, migration_script):
upgrade_ops = migration_script.upgrade_ops_list[-1]
downgrade_ops = migration_script.downgrade_ops_list[-1]
_produce_net_changes(autogen_context, upgrade_ops)
upgrade_ops.reverse_into(downgrade_ops)
comparators = util.Dispatcher(uselist=True)
def _produce_net_changes(autogen_context, upgrade_ops):
connection = autogen_context.connection
include_schemas = autogen_context.opts.get('include_schemas', False)
inspector = Inspector.from_engine(connection)
default_schema = connection.dialect.default_schema_name
if include_schemas:
schemas = set(inspector.get_schema_names())
# replace default schema name with None
schemas.discard("information_schema")
# replace the "default" schema with None
schemas.add(None)
schemas.discard(default_schema)
else:
schemas = [None]
comparators.dispatch("schema", autogen_context.dialect.name)(
autogen_context, upgrade_ops, schemas
)
@comparators.dispatch_for("schema")
def _autogen_for_tables(autogen_context, upgrade_ops, schemas):
inspector = autogen_context.inspector
metadata = autogen_context.metadata
conn_table_names = set()
version_table_schema = \
autogen_context.migration_context.version_table_schema
version_table = autogen_context.migration_context.version_table
for s in schemas:
tables = set(inspector.get_table_names(schema=s))
if s == version_table_schema:
tables = tables.difference(
[autogen_context.migration_context.version_table]
)
conn_table_names.update(zip([s] * len(tables), tables))
metadata_table_names = OrderedSet(
[(table.schema, table.name) for table in metadata.sorted_tables]
).difference([(version_table_schema, version_table)])
_compare_tables(conn_table_names, metadata_table_names,
inspector, metadata, upgrade_ops, autogen_context)
def _compare_tables(conn_table_names, metadata_table_names,
inspector, metadata, upgrade_ops, autogen_context):
default_schema = inspector.bind.dialect.default_schema_name
# tables coming from the connection will not have "schema"
# set if it matches default_schema_name; so we need a list
# of table names from local metadata that also have "None" if schema
# == default_schema_name. Most setups will be like this anyway but
# some are not (see #170)
metadata_table_names_no_dflt_schema = OrderedSet([
(schema if schema != default_schema else None, tname)
for schema, tname in metadata_table_names
])
# to adjust for the MetaData collection storing the tables either
# as "schemaname.tablename" or just "tablename", create a new lookup
# which will match the "non-default-schema" keys to the Table object.
tname_to_table = dict(
(
no_dflt_schema,
metadata.tables[sa_schema._get_table_key(tname, schema)]
)
for no_dflt_schema, (schema, tname) in zip(
metadata_table_names_no_dflt_schema,
metadata_table_names)
)
metadata_table_names = metadata_table_names_no_dflt_schema
for s, tname in metadata_table_names.difference(conn_table_names):
name = '%s.%s' % (s, tname) if s else tname
metadata_table = tname_to_table[(s, tname)]
if autogen_context.run_filters(
metadata_table, tname, "table", False, None):
upgrade_ops.ops.append(
ops.CreateTableOp.from_table(metadata_table))
log.info("Detected added table %r", name)
modify_table_ops = ops.ModifyTableOps(tname, [], schema=s)
comparators.dispatch("table")(
autogen_context, modify_table_ops,
s, tname, None, metadata_table
)
if not modify_table_ops.is_empty():
upgrade_ops.ops.append(modify_table_ops)
removal_metadata = sa_schema.MetaData()
for s, tname in conn_table_names.difference(metadata_table_names):
name = sa_schema._get_table_key(tname, s)
exists = name in removal_metadata.tables
t = sa_schema.Table(tname, removal_metadata, schema=s)
if not exists:
event.listen(
t,
"column_reflect",
autogen_context.migration_context.impl.
_compat_autogen_column_reflect(inspector))
inspector.reflecttable(t, None)
if autogen_context.run_filters(t, tname, "table", True, None):
upgrade_ops.ops.append(
ops.DropTableOp.from_table(t)
)
log.info("Detected removed table %r", name)
existing_tables = conn_table_names.intersection(metadata_table_names)
existing_metadata = sa_schema.MetaData()
conn_column_info = {}
for s, tname in existing_tables:
name = sa_schema._get_table_key(tname, s)
exists = name in existing_metadata.tables
t = sa_schema.Table(tname, existing_metadata, schema=s)
if not exists:
event.listen(
t,
"column_reflect",
autogen_context.migration_context.impl.
_compat_autogen_column_reflect(inspector))
inspector.reflecttable(t, None)
conn_column_info[(s, tname)] = t
for s, tname in sorted(existing_tables, key=lambda x: (x[0] or '', x[1])):
s = s or None
name = '%s.%s' % (s, tname) if s else tname
metadata_table = tname_to_table[(s, tname)]
conn_table = existing_metadata.tables[name]
if autogen_context.run_filters(
metadata_table, tname, "table", False,
conn_table):
modify_table_ops = ops.ModifyTableOps(tname, [], schema=s)
with _compare_columns(
s, tname,
conn_table,
metadata_table,
modify_table_ops, autogen_context, inspector):
comparators.dispatch("table")(
autogen_context, modify_table_ops,
s, tname, conn_table, metadata_table
)
if not modify_table_ops.is_empty():
upgrade_ops.ops.append(modify_table_ops)
def _make_index(params, conn_table):
# TODO: add .info such as 'duplicates_constraint'
return sa_schema.Index(
params['name'],
*[conn_table.c[cname] for cname in params['column_names']],
unique=params['unique']
)
def _make_unique_constraint(params, conn_table):
# TODO: add .info such as 'duplicates_index'
return sa_schema.UniqueConstraint(
*[conn_table.c[cname] for cname in params['column_names']],
name=params['name']
)
def _make_foreign_key(params, conn_table):
tname = params['referred_table']
if params['referred_schema']:
tname = "%s.%s" % (params['referred_schema'], tname)
options = params.get('options', {})
const = sa_schema.ForeignKeyConstraint(
[conn_table.c[cname] for cname in params['constrained_columns']],
["%s.%s" % (tname, n) for n in params['referred_columns']],
onupdate=options.get('onupdate'),
ondelete=options.get('ondelete'),
deferrable=options.get('deferrable'),
initially=options.get('initially'),
name=params['name']
)
# needed by 0.7
conn_table.append_constraint(const)
return const
@contextlib.contextmanager
def _compare_columns(schema, tname, conn_table, metadata_table,
modify_table_ops, autogen_context, inspector):
name = '%s.%s' % (schema, tname) if schema else tname
metadata_cols_by_name = dict((c.name, c) for c in metadata_table.c)
conn_col_names = dict((c.name, c) for c in conn_table.c)
metadata_col_names = OrderedSet(sorted(metadata_cols_by_name))
for cname in metadata_col_names.difference(conn_col_names):
if autogen_context.run_filters(
metadata_cols_by_name[cname], cname,
"column", False, None):
modify_table_ops.ops.append(
ops.AddColumnOp.from_column_and_tablename(
schema, tname, metadata_cols_by_name[cname])
)
log.info("Detected added column '%s.%s'", name, cname)
for colname in metadata_col_names.intersection(conn_col_names):
metadata_col = metadata_cols_by_name[colname]
conn_col = conn_table.c[colname]
if not autogen_context.run_filters(
metadata_col, colname, "column", False,
conn_col):
continue
alter_column_op = ops.AlterColumnOp(
tname, colname, schema=schema)
comparators.dispatch("column")(
autogen_context, alter_column_op,
schema, tname, colname, conn_col, metadata_col
)
if alter_column_op.has_changes():
modify_table_ops.ops.append(alter_column_op)
yield
for cname in set(conn_col_names).difference(metadata_col_names):
if autogen_context.run_filters(
conn_table.c[cname], cname,
"column", True, None):
modify_table_ops.ops.append(
ops.DropColumnOp.from_column_and_tablename(
schema, tname, conn_table.c[cname]
)
)
log.info("Detected removed column '%s.%s'", name, cname)
class _constraint_sig(object):
def __eq__(self, other):
return self.const == other.const
def __ne__(self, other):
return self.const != other.const
def __hash__(self):
return hash(self.const)
class _uq_constraint_sig(_constraint_sig):
is_index = False
is_unique = True
def __init__(self, const):
self.const = const
self.name = const.name
self.sig = tuple(sorted([col.name for col in const.columns]))
@property
def column_names(self):
return [col.name for col in self.const.columns]
class _ix_constraint_sig(_constraint_sig):
is_index = True
def __init__(self, const):
self.const = const
self.name = const.name
self.sig = tuple(sorted([col.name for col in const.columns]))
self.is_unique = bool(const.unique)
@property
def column_names(self):
return sqla_compat._get_index_column_names(self.const)
class _fk_constraint_sig(_constraint_sig):
def __init__(self, const, include_options=False):
self.const = const
self.name = const.name
(
self.source_schema, self.source_table,
self.source_columns, self.target_schema, self.target_table,
self.target_columns,
onupdate, ondelete,
deferrable, initially) = _fk_spec(const)
self.sig = (
self.source_schema, self.source_table, tuple(self.source_columns),
self.target_schema, self.target_table, tuple(self.target_columns)
)
if include_options:
self.sig += (
(None if onupdate.lower() == 'no action'
else onupdate.lower())
if onupdate else None,
(None if ondelete.lower() == 'no action'
else ondelete.lower())
if ondelete else None,
# convert initially + deferrable into one three-state value
"initially_deferrable"
if initially and initially.lower() == "deferred"
else "deferrable" if deferrable
else "not deferrable"
)
@comparators.dispatch_for("table")
def _compare_indexes_and_uniques(
autogen_context, modify_ops, schema, tname, conn_table,
metadata_table):
inspector = autogen_context.inspector
is_create_table = conn_table is None
# 1a. get raw indexes and unique constraints from metadata ...
metadata_unique_constraints = set(
uq for uq in metadata_table.constraints
if isinstance(uq, sa_schema.UniqueConstraint)
)
metadata_indexes = set(metadata_table.indexes)
conn_uniques = conn_indexes = frozenset()
supports_unique_constraints = False
if conn_table is not None:
# 1b. ... and from connection, if the table exists
if hasattr(inspector, "get_unique_constraints"):
try:
conn_uniques = inspector.get_unique_constraints(
tname, schema=schema)
supports_unique_constraints = True
except NotImplementedError:
pass
try:
conn_indexes = inspector.get_indexes(tname, schema=schema)
except NotImplementedError:
pass
# 2. convert conn-level objects from raw inspector records
# into schema objects
conn_uniques = set(_make_unique_constraint(uq_def, conn_table)
for uq_def in conn_uniques)
conn_indexes = set(_make_index(ix, conn_table) for ix in conn_indexes)
# 3. give the dialect a chance to omit indexes and constraints that
# we know are either added implicitly by the DB or that the DB
# can't accurately report on
autogen_context.migration_context.impl.\
correct_for_autogen_constraints(
conn_uniques, conn_indexes,
metadata_unique_constraints,
metadata_indexes)
# 4. organize the constraints into "signature" collections, the
# _constraint_sig() objects provide a consistent facade over both
# Index and UniqueConstraint so we can easily work with them
# interchangeably
metadata_unique_constraints = set(_uq_constraint_sig(uq)
for uq in metadata_unique_constraints
)
metadata_indexes = set(_ix_constraint_sig(ix) for ix in metadata_indexes)
conn_unique_constraints = set(
_uq_constraint_sig(uq) for uq in conn_uniques)
conn_indexes = set(_ix_constraint_sig(ix) for ix in conn_indexes)
# 5. index things by name, for those objects that have names
metadata_names = dict(
(c.name, c) for c in
metadata_unique_constraints.union(metadata_indexes)
if c.name is not None)
conn_uniques_by_name = dict((c.name, c) for c in conn_unique_constraints)
conn_indexes_by_name = dict((c.name, c) for c in conn_indexes)
conn_names = dict((c.name, c) for c in
conn_unique_constraints.union(conn_indexes)
if c.name is not None)
doubled_constraints = dict(
(name, (conn_uniques_by_name[name], conn_indexes_by_name[name]))
for name in set(
conn_uniques_by_name).intersection(conn_indexes_by_name)
)
# 6. index things by "column signature", to help with unnamed unique
# constraints.
conn_uniques_by_sig = dict((uq.sig, uq) for uq in conn_unique_constraints)
metadata_uniques_by_sig = dict(
(uq.sig, uq) for uq in metadata_unique_constraints)
metadata_indexes_by_sig = dict(
(ix.sig, ix) for ix in metadata_indexes)
unnamed_metadata_uniques = dict(
(uq.sig, uq) for uq in
metadata_unique_constraints if uq.name is None)
# assumptions:
# 1. a unique constraint or an index from the connection *always*
# has a name.
# 2. an index on the metadata side *always* has a name.
# 3. a unique constraint on the metadata side *might* have a name.
# 4. The backend may double up indexes as unique constraints and
# vice versa (e.g. MySQL, Postgresql)
def obj_added(obj):
if obj.is_index:
if autogen_context.run_filters(
obj.const, obj.name, "index", False, None):
modify_ops.ops.append(
ops.CreateIndexOp.from_index(obj.const)
)
log.info("Detected added index '%s' on %s",
obj.name, ', '.join([
"'%s'" % obj.column_names
]))
else:
if not supports_unique_constraints:
# can't report unique indexes as added if we don't
# detect them
return
if is_create_table:
# unique constraints are created inline with table defs
return
if autogen_context.run_filters(
obj.const, obj.name,
"unique_constraint", False, None):
modify_ops.ops.append(
ops.AddConstraintOp.from_constraint(obj.const)
)
log.info("Detected added unique constraint '%s' on %s",
obj.name, ', '.join([
"'%s'" % obj.column_names
]))
def obj_removed(obj):
if obj.is_index:
if obj.is_unique and not supports_unique_constraints:
# many databases double up unique constraints
# as unique indexes. without that list we can't
# be sure what we're doing here
return
if autogen_context.run_filters(
obj.const, obj.name, "index", True, None):
modify_ops.ops.append(
ops.DropIndexOp.from_index(obj.const)
)
log.info(
"Detected removed index '%s' on '%s'", obj.name, tname)
else:
if autogen_context.run_filters(
obj.const, obj.name,
"unique_constraint", True, None):
modify_ops.ops.append(
ops.DropConstraintOp.from_constraint(obj.const)
)
log.info("Detected removed unique constraint '%s' on '%s'",
obj.name, tname
)
def obj_changed(old, new, msg):
if old.is_index:
if autogen_context.run_filters(
new.const, new.name, "index",
False, old.const):
log.info("Detected changed index '%s' on '%s':%s",
old.name, tname, ', '.join(msg)
)
modify_ops.ops.append(
ops.DropIndexOp.from_index(old.const)
)
modify_ops.ops.append(
ops.CreateIndexOp.from_index(new.const)
)
else:
if autogen_context.run_filters(
new.const, new.name,
"unique_constraint", False, old.const):
log.info("Detected changed unique constraint '%s' on '%s':%s",
old.name, tname, ', '.join(msg)
)
modify_ops.ops.append(
ops.DropConstraintOp.from_constraint(old.const)
)
modify_ops.ops.append(
ops.AddConstraintOp.from_constraint(new.const)
)
for added_name in sorted(set(metadata_names).difference(conn_names)):
obj = metadata_names[added_name]
obj_added(obj)
for existing_name in sorted(set(metadata_names).intersection(conn_names)):
metadata_obj = metadata_names[existing_name]
if existing_name in doubled_constraints:
conn_uq, conn_idx = doubled_constraints[existing_name]
if metadata_obj.is_index:
conn_obj = conn_idx
else:
conn_obj = conn_uq
else:
conn_obj = conn_names[existing_name]
if conn_obj.is_index != metadata_obj.is_index:
obj_removed(conn_obj)
obj_added(metadata_obj)
else:
msg = []
if conn_obj.is_unique != metadata_obj.is_unique:
msg.append(' unique=%r to unique=%r' % (
conn_obj.is_unique, metadata_obj.is_unique
))
if conn_obj.sig != metadata_obj.sig:
msg.append(' columns %r to %r' % (
conn_obj.sig, metadata_obj.sig
))
if msg:
obj_changed(conn_obj, metadata_obj, msg)
for removed_name in sorted(set(conn_names).difference(metadata_names)):
conn_obj = conn_names[removed_name]
if not conn_obj.is_index and conn_obj.sig in unnamed_metadata_uniques:
continue
elif removed_name in doubled_constraints:
if conn_obj.sig not in metadata_indexes_by_sig and \
conn_obj.sig not in metadata_uniques_by_sig:
conn_uq, conn_idx = doubled_constraints[removed_name]
obj_removed(conn_uq)
obj_removed(conn_idx)
else:
obj_removed(conn_obj)
for uq_sig in unnamed_metadata_uniques:
if uq_sig not in conn_uniques_by_sig:
obj_added(unnamed_metadata_uniques[uq_sig])
@comparators.dispatch_for("column")
def _compare_nullable(
autogen_context, alter_column_op, schema, tname, cname, conn_col,
metadata_col):
# work around SQLAlchemy issue #3023
if metadata_col.primary_key:
return
metadata_col_nullable = metadata_col.nullable
conn_col_nullable = conn_col.nullable
alter_column_op.existing_nullable = conn_col_nullable
if conn_col_nullable is not metadata_col_nullable:
alter_column_op.modify_nullable = metadata_col_nullable
log.info("Detected %s on column '%s.%s'",
"NULL" if metadata_col_nullable else "NOT NULL",
tname,
cname
)
@comparators.dispatch_for("column")
def _compare_type(
autogen_context, alter_column_op, schema, tname, cname, conn_col,
metadata_col):
conn_type = conn_col.type
alter_column_op.existing_type = conn_type
metadata_type = metadata_col.type
if conn_type._type_affinity is sqltypes.NullType:
log.info("Couldn't determine database type "
"for column '%s.%s'", tname, cname)
return
if metadata_type._type_affinity is sqltypes.NullType:
log.info("Column '%s.%s' has no type within "
"the model; can't compare", tname, cname)
return
isdiff = autogen_context.migration_context._compare_type(
conn_col, metadata_col)
if isdiff:
alter_column_op.modify_type = metadata_type
log.info("Detected type change from %r to %r on '%s.%s'",
conn_type, metadata_type, tname, cname
)
def _render_server_default_for_compare(metadata_default,
metadata_col, autogen_context):
rendered = _user_defined_render(
"server_default", metadata_default, autogen_context)
if rendered is not False:
return rendered
if isinstance(metadata_default, sa_schema.DefaultClause):
if isinstance(metadata_default.arg, compat.string_types):
metadata_default = metadata_default.arg
else:
metadata_default = str(metadata_default.arg.compile(
dialect=autogen_context.dialect))
if isinstance(metadata_default, compat.string_types):
if metadata_col.type._type_affinity is sqltypes.String:
metadata_default = re.sub(r"^'|'$", "", metadata_default)
return repr(metadata_default)
else:
return metadata_default
else:
return None
@comparators.dispatch_for("column")
def _compare_server_default(
autogen_context, alter_column_op, schema, tname, cname,
conn_col, metadata_col):
metadata_default = metadata_col.server_default
conn_col_default = conn_col.server_default
if conn_col_default is None and metadata_default is None:
return False
rendered_metadata_default = _render_server_default_for_compare(
metadata_default, metadata_col, autogen_context)
rendered_conn_default = conn_col.server_default.arg.text \
if conn_col.server_default else None
alter_column_op.existing_server_default = conn_col_default
isdiff = autogen_context.migration_context._compare_server_default(
conn_col, metadata_col,
rendered_metadata_default,
rendered_conn_default
)
if isdiff:
alter_column_op.modify_server_default = metadata_default
log.info(
"Detected server default on column '%s.%s'",
tname, cname)
@comparators.dispatch_for("table")
def _compare_foreign_keys(
autogen_context, modify_table_ops, schema, tname, conn_table,
metadata_table):
# if we're doing CREATE TABLE, all FKs are created
# inline within the table def
if conn_table is None:
return
inspector = autogen_context.inspector
metadata_fks = set(
fk for fk in metadata_table.constraints
if isinstance(fk, sa_schema.ForeignKeyConstraint)
)
conn_fks = inspector.get_foreign_keys(tname, schema=schema)
backend_reflects_fk_options = conn_fks and 'options' in conn_fks[0]
conn_fks = set(_make_foreign_key(const, conn_table) for const in conn_fks)
# give the dialect a chance to correct the FKs to match more
# closely
autogen_context.migration_context.impl.\
correct_for_autogen_foreignkeys(
conn_fks, metadata_fks,
)
metadata_fks = set(
_fk_constraint_sig(fk, include_options=backend_reflects_fk_options)
for fk in metadata_fks
)
conn_fks = set(
_fk_constraint_sig(fk, include_options=backend_reflects_fk_options)
for fk in conn_fks
)
conn_fks_by_sig = dict(
(c.sig, c) for c in conn_fks
)
metadata_fks_by_sig = dict(
(c.sig, c) for c in metadata_fks
)
metadata_fks_by_name = dict(
(c.name, c) for c in metadata_fks if c.name is not None
)
conn_fks_by_name = dict(
(c.name, c) for c in conn_fks if c.name is not None
)
def _add_fk(obj, compare_to):
if autogen_context.run_filters(
obj.const, obj.name, "foreign_key_constraint", False,
compare_to):
modify_table_ops.ops.append(
ops.CreateForeignKeyOp.from_constraint(const.const)
)
log.info(
"Detected added foreign key (%s)(%s) on table %s%s",
", ".join(obj.source_columns),
", ".join(obj.target_columns),
"%s." % obj.source_schema if obj.source_schema else "",
obj.source_table)
def _remove_fk(obj, compare_to):
if autogen_context.run_filters(
obj.const, obj.name, "foreign_key_constraint", True,
compare_to):
modify_table_ops.ops.append(
ops.DropConstraintOp.from_constraint(obj.const)
)
log.info(
"Detected removed foreign key (%s)(%s) on table %s%s",
", ".join(obj.source_columns),
", ".join(obj.target_columns),
"%s." % obj.source_schema if obj.source_schema else "",
obj.source_table)
# so far it appears we don't need to do this by name at all.
# SQLite doesn't preserve constraint names anyway
for removed_sig in set(conn_fks_by_sig).difference(metadata_fks_by_sig):
const = conn_fks_by_sig[removed_sig]
if removed_sig not in metadata_fks_by_sig:
compare_to = metadata_fks_by_name[const.name].const \
if const.name in metadata_fks_by_name else None
_remove_fk(const, compare_to)
for added_sig in set(metadata_fks_by_sig).difference(conn_fks_by_sig):
const = metadata_fks_by_sig[added_sig]
if added_sig not in conn_fks_by_sig:
compare_to = conn_fks_by_name[const.name].const \
if const.name in conn_fks_by_name else None
_add_fk(const, compare_to)
Mini Shell