def models(cls) -> Dict[str, Type[model.Model]]:
"""Constructs model classes from Spanner table schema."""
tables = cls.tables()
indexes = cls.indexes()
models = {}
for table_name, table_data in tables.items():
primary_index = indexes[table_name][index.Index.PRIMARY_INDEX]
primary_keys = set(primary_index.columns)
klass = model.ModelMetaclass(
cls._class_name_from_table(table_name), (model.Model,), {}
)
for model_field in table_data["fields"].values():
model_field._primary_key = (
model_field.name in primary_keys
) # pylint: disable=protected-access
klass.meta = metadata.ModelMetadata(
table=table_name,
fields=table_data["fields"],
interleaved=cls._class_name_from_table(table_data["parent_table"]),
indexes=indexes[table_name],
model_class=klass,
)
klass.meta.finalize(reregister_model=True)
models[table_name] = klass
return models
def __new__(mcs, name: str, bases: Any, attrs: Dict[str, Any],
**kwargs: Any):
parents = [base for base in bases if isinstance(base, ModelMetaclass)]
if not parents:
return super().__new__(mcs, name, bases, attrs, **kwargs)
model_metadata = metadata.ModelMetadata()
for parent in parents:
if 'meta' in vars(parent):
model_metadata.add_metadata(parent.meta)
non_model_attrs = {}
for key, value in attrs.items():
if key == '__table__':
model_metadata.table = value
elif key == '__interleaved__':
model_metadata.interleaved = value
if isinstance(value, field.Field):
model_metadata.add_field(key, value)
elif isinstance(value, index.Index):
model_metadata.add_index(key, value)
elif isinstance(value, relationship.Relationship):
model_metadata.add_relation(key, value)
else:
non_model_attrs[key] = value
cls = super().__new__(mcs, name, bases, non_model_attrs, **kwargs)
# If a table is set, this class represents a complete model, so finalize
# the metadata
if model_metadata.table:
model_metadata.model_class = cls
model_metadata.finalize()
cls.meta = model_metadata
return cls