openmedialibrary_platform/Linux/lib/python2.7/site-packages/alembic/autogenerate/compare.py

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2013-10-11 17:28:32 +00:00
from sqlalchemy.exc import NoSuchTableError
from sqlalchemy import schema as sa_schema, types as sqltypes
import logging
from .. import compat
from .render import _render_server_default
from sqlalchemy.util import OrderedSet
log = logging.getLogger(__name__)
def _run_filters(object_, name, type_, reflected, compare_to, object_filters):
for fn in object_filters:
if not fn(object_, name, type_, reflected, compare_to):
return False
else:
return True
def _compare_tables(conn_table_names, metadata_table_names,
object_filters,
inspector, metadata, diffs, 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 _run_filters(metadata_table, tname, "table", False, None, object_filters):
diffs.append(("add_table", metadata_table))
log.info("Detected added table %r", name)
_compare_indexes_and_uniques(s, tname, object_filters,
None,
metadata_table,
diffs, autogen_context, inspector)
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:
inspector.reflecttable(t, None)
if _run_filters(t, tname, "table", True, None, object_filters):
diffs.append(("remove_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:
inspector.reflecttable(t, None)
conn_column_info[(s, tname)] = t
for s, tname in sorted(existing_tables):
name = '%s.%s' % (s, tname) if s else tname
metadata_table = tname_to_table[(s, tname)]
conn_table = existing_metadata.tables[name]
if _run_filters(metadata_table, tname, "table", False, conn_table, object_filters):
_compare_columns(s, tname, object_filters,
conn_table,
metadata_table,
diffs, autogen_context, inspector)
_compare_indexes_and_uniques(s, tname, object_filters,
conn_table,
metadata_table,
diffs, autogen_context, inspector)
# TODO:
# table constraints
# sequences
def _make_index(params, conn_table):
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):
return sa_schema.UniqueConstraint(
*[conn_table.c[cname] for cname in params['column_names']],
name=params['name']
)
def _compare_columns(schema, tname, object_filters, conn_table, metadata_table,
diffs, 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 _run_filters(metadata_cols_by_name[cname], cname,
"column", False, None, object_filters):
diffs.append(
("add_column", schema, tname, metadata_cols_by_name[cname])
)
log.info("Detected added column '%s.%s'", name, cname)
for cname in set(conn_col_names).difference(metadata_col_names):
if _run_filters(conn_table.c[cname], cname,
"column", True, None, object_filters):
diffs.append(
("remove_column", schema, tname, conn_table.c[cname])
)
log.info("Detected removed 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 _run_filters(
metadata_col, colname, "column", False, conn_col, object_filters):
continue
col_diff = []
_compare_type(schema, tname, colname,
conn_col,
metadata_col,
col_diff, autogen_context
)
_compare_nullable(schema, tname, colname,
conn_col,
metadata_col.nullable,
col_diff, autogen_context
)
_compare_server_default(schema, tname, colname,
conn_col,
metadata_col,
col_diff, autogen_context
)
if col_diff:
diffs.append(col_diff)
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 _get_index_column_names(self.const)
def _get_index_column_names(idx):
if compat.sqla_08:
return [getattr(exp, "name", None) for exp in idx.expressions]
else:
return [getattr(col, "name", None) for col in idx.columns]
def _compare_indexes_and_uniques(schema, tname, object_filters, conn_table,
metadata_table, diffs, 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['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:
diffs.append(("add_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
diffs.append(("add_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
diffs.append(("remove_index", obj.const))
log.info("Detected removed index '%s' on '%s'", obj.name, tname)
else:
diffs.append(("remove_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:
log.info("Detected changed index '%s' on '%s':%s",
old.name, tname, ', '.join(msg)
)
diffs.append(("remove_index", old.const))
diffs.append(("add_index", new.const))
else:
log.info("Detected changed unique constraint '%s' on '%s':%s",
old.name, tname, ', '.join(msg)
)
diffs.append(("remove_constraint", old.const))
diffs.append(("add_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])
def _compare_nullable(schema, tname, cname, conn_col,
metadata_col_nullable, diffs,
autogen_context):
conn_col_nullable = conn_col.nullable
if conn_col_nullable is not metadata_col_nullable:
diffs.append(
("modify_nullable", schema, tname, cname,
{
"existing_type": conn_col.type,
"existing_server_default": conn_col.server_default,
},
conn_col_nullable,
metadata_col_nullable),
)
log.info("Detected %s on column '%s.%s'",
"NULL" if metadata_col_nullable else "NOT NULL",
tname,
cname
)
def _compare_type(schema, tname, cname, conn_col,
metadata_col, diffs,
autogen_context):
conn_type = conn_col.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['context']._compare_type(conn_col, metadata_col)
if isdiff:
diffs.append(
("modify_type", schema, tname, cname,
{
"existing_nullable": conn_col.nullable,
"existing_server_default": conn_col.server_default,
},
conn_type,
metadata_type),
)
log.info("Detected type change from %r to %r on '%s.%s'",
conn_type, metadata_type, tname, cname
)
def _compare_server_default(schema, tname, cname, conn_col, metadata_col,
diffs, autogen_context):
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(
metadata_default, autogen_context)
rendered_conn_default = conn_col.server_default.arg.text \
if conn_col.server_default else None
isdiff = autogen_context['context']._compare_server_default(
conn_col, metadata_col,
rendered_metadata_default,
rendered_conn_default
)
if isdiff:
conn_col_default = rendered_conn_default
diffs.append(
("modify_default", schema, tname, cname,
{
"existing_nullable": conn_col.nullable,
"existing_type": conn_col.type,
},
conn_col_default,
metadata_default),
)
log.info("Detected server default on column '%s.%s'",
tname,
cname
)