Edit File: batch.py
from __future__ import annotations from typing import Any from typing import Dict from typing import List from typing import Optional from typing import Tuple from typing import TYPE_CHECKING from typing import Union from sqlalchemy import CheckConstraint from sqlalchemy import Column from sqlalchemy import ForeignKeyConstraint from sqlalchemy import Index from sqlalchemy import MetaData from sqlalchemy import PrimaryKeyConstraint from sqlalchemy import schema as sql_schema from sqlalchemy import Table from sqlalchemy import types as sqltypes from sqlalchemy.events import SchemaEventTarget from sqlalchemy.util import OrderedDict from sqlalchemy.util import topological from ..util import exc from ..util.sqla_compat import _columns_for_constraint from ..util.sqla_compat import _copy from ..util.sqla_compat import _copy_expression from ..util.sqla_compat import _ensure_scope_for_ddl from ..util.sqla_compat import _fk_is_self_referential from ..util.sqla_compat import _idx_table_bound_expressions from ..util.sqla_compat import _insert_inline from ..util.sqla_compat import _is_type_bound from ..util.sqla_compat import _remove_column_from_collection from ..util.sqla_compat import _resolve_for_variant from ..util.sqla_compat import _select from ..util.sqla_compat import constraint_name_defined from ..util.sqla_compat import constraint_name_string if TYPE_CHECKING: from typing import Literal from sqlalchemy.engine import Dialect from sqlalchemy.sql.elements import ColumnClause from sqlalchemy.sql.elements import quoted_name from sqlalchemy.sql.functions import Function from sqlalchemy.sql.schema import Constraint from sqlalchemy.sql.type_api import TypeEngine from ..ddl.impl import DefaultImpl class BatchOperationsImpl: def __init__( self, operations, table_name, schema, recreate, copy_from, table_args, table_kwargs, reflect_args, reflect_kwargs, naming_convention, partial_reordering, ): self.operations = operations self.table_name = table_name self.schema = schema if recreate not in ("auto", "always", "never"): raise ValueError( "recreate may be one of 'auto', 'always', or 'never'." ) self.recreate = recreate self.copy_from = copy_from self.table_args = table_args self.table_kwargs = dict(table_kwargs) self.reflect_args = reflect_args self.reflect_kwargs = dict(reflect_kwargs) self.reflect_kwargs.setdefault( "listeners", list(self.reflect_kwargs.get("listeners", ())) ) self.reflect_kwargs["listeners"].append( ("column_reflect", operations.impl.autogen_column_reflect) ) self.naming_convention = naming_convention self.partial_reordering = partial_reordering self.batch = [] @property def dialect(self) -> Dialect: return self.operations.impl.dialect @property def impl(self) -> DefaultImpl: return self.operations.impl def _should_recreate(self) -> bool: if self.recreate == "auto": return self.operations.impl.requires_recreate_in_batch(self) elif self.recreate == "always": return True else: return False def flush(self) -> None: should_recreate = self._should_recreate() with _ensure_scope_for_ddl(self.impl.connection): if not should_recreate: for opname, arg, kw in self.batch: fn = getattr(self.operations.impl, opname) fn(*arg, **kw) else: if self.naming_convention: m1 = MetaData(naming_convention=self.naming_convention) else: m1 = MetaData() if self.copy_from is not None: existing_table = self.copy_from reflected = False else: if self.operations.migration_context.as_sql: raise exc.CommandError( f"This operation cannot proceed in --sql mode; " f"batch mode with dialect " f"{self.operations.migration_context.dialect.name} " # noqa: E501 f"requires a live database connection with which " f'to reflect the table "{self.table_name}". ' f"To generate a batch SQL migration script using " "table " '"move and copy", a complete Table object ' f'should be passed to the "copy_from" argument ' "of the batch_alter_table() method so that table " "reflection can be skipped." ) existing_table = Table( self.table_name, m1, schema=self.schema, autoload_with=self.operations.get_bind(), *self.reflect_args, **self.reflect_kwargs, ) reflected = True batch_impl = ApplyBatchImpl( self.impl, existing_table, self.table_args, self.table_kwargs, reflected, partial_reordering=self.partial_reordering, ) for opname, arg, kw in self.batch: fn = getattr(batch_impl, opname) fn(*arg, **kw) batch_impl._create(self.impl) def alter_column(self, *arg, **kw) -> None: self.batch.append(("alter_column", arg, kw)) def add_column(self, *arg, **kw) -> None: if ( "insert_before" in kw or "insert_after" in kw ) and not self._should_recreate(): raise exc.CommandError( "Can't specify insert_before or insert_after when using " "ALTER; please specify recreate='always'" ) self.batch.append(("add_column", arg, kw)) def drop_column(self, *arg, **kw) -> None: self.batch.append(("drop_column", arg, kw)) def add_constraint(self, const: Constraint) -> None: self.batch.append(("add_constraint", (const,), {})) def drop_constraint(self, const: Constraint) -> None: self.batch.append(("drop_constraint", (const,), {})) def rename_table(self, *arg, **kw): self.batch.append(("rename_table", arg, kw)) def create_index(self, idx: Index) -> None: self.batch.append(("create_index", (idx,), {})) def drop_index(self, idx: Index) -> None: self.batch.append(("drop_index", (idx,), {})) def create_table_comment(self, table): self.batch.append(("create_table_comment", (table,), {})) def drop_table_comment(self, table): self.batch.append(("drop_table_comment", (table,), {})) def create_table(self, table): raise NotImplementedError("Can't create table in batch mode") def drop_table(self, table): raise NotImplementedError("Can't drop table in batch mode") def create_column_comment(self, column): self.batch.append(("create_column_comment", (column,), {})) class ApplyBatchImpl: def __init__( self, impl: DefaultImpl, table: Table, table_args: tuple, table_kwargs: Dict[str, Any], reflected: bool, partial_reordering: tuple = (), ) -> None: self.impl = impl self.table = table # this is a Table object self.table_args = table_args self.table_kwargs = table_kwargs self.temp_table_name = self._calc_temp_name(table.name) self.new_table: Optional[Table] = None self.partial_reordering = partial_reordering # tuple of tuples self.add_col_ordering: Tuple[ Tuple[str, str], ... ] = () # tuple of tuples self.column_transfers = OrderedDict( (c.name, {"expr": c}) for c in self.table.c ) self.existing_ordering = list(self.column_transfers) self.reflected = reflected self._grab_table_elements() @classmethod def _calc_temp_name(cls, tablename: Union[quoted_name, str]) -> str: return ("_alembic_tmp_%s" % tablename)[0:50] def _grab_table_elements(self) -> None: schema = self.table.schema self.columns: Dict[str, Column[Any]] = OrderedDict() for c in self.table.c: c_copy = _copy(c, schema=schema) c_copy.unique = c_copy.index = False # ensure that the type object was copied, # as we may need to modify it in-place if isinstance(c.type, SchemaEventTarget): assert c_copy.type is not c.type self.columns[c.name] = c_copy self.named_constraints: Dict[str, Constraint] = {} self.unnamed_constraints = [] self.col_named_constraints = {} self.indexes: Dict[str, Index] = {} self.new_indexes: Dict[str, Index] = {} for const in self.table.constraints: if _is_type_bound(const): continue elif ( self.reflected and isinstance(const, CheckConstraint) and not const.name ): # TODO: we are skipping unnamed reflected CheckConstraint # because # we have no way to determine _is_type_bound() for these. pass elif constraint_name_string(const.name): self.named_constraints[const.name] = const else: self.unnamed_constraints.append(const) if not self.reflected: for col in self.table.c: for const in col.constraints: if const.name: self.col_named_constraints[const.name] = (col, const) for idx in self.table.indexes: self.indexes[idx.name] = idx # type: ignore[index] for k in self.table.kwargs: self.table_kwargs.setdefault(k, self.table.kwargs[k]) def _adjust_self_columns_for_partial_reordering(self) -> None: pairs = set() col_by_idx = list(self.columns) if self.partial_reordering: for tuple_ in self.partial_reordering: for index, elem in enumerate(tuple_): if index > 0: pairs.add((tuple_[index - 1], elem)) else: for index, elem in enumerate(self.existing_ordering): if index > 0: pairs.add((col_by_idx[index - 1], elem)) pairs.update(self.add_col_ordering) # this can happen if some columns were dropped and not removed # from existing_ordering. this should be prevented already, but # conservatively making sure this didn't happen pairs_list = [p for p in pairs if p[0] != p[1]] sorted_ = list( topological.sort(pairs_list, col_by_idx, deterministic_order=True) ) self.columns = OrderedDict((k, self.columns[k]) for k in sorted_) self.column_transfers = OrderedDict( (k, self.column_transfers[k]) for k in sorted_ ) def _transfer_elements_to_new_table(self) -> None: assert self.new_table is None, "Can only create new table once" m = MetaData() schema = self.table.schema if self.partial_reordering or self.add_col_ordering: self._adjust_self_columns_for_partial_reordering() self.new_table = new_table = Table( self.temp_table_name, m, *(list(self.columns.values()) + list(self.table_args)), schema=schema, **self.table_kwargs, ) for const in ( list(self.named_constraints.values()) + self.unnamed_constraints ): const_columns = {c.key for c in _columns_for_constraint(const)} if not const_columns.issubset(self.column_transfers): continue const_copy: Constraint if isinstance(const, ForeignKeyConstraint): if _fk_is_self_referential(const): # for self-referential constraint, refer to the # *original* table name, and not _alembic_batch_temp. # This is consistent with how we're handling # FK constraints from other tables; we assume SQLite # no foreign keys just keeps the names unchanged, so # when we rename back, they match again. const_copy = _copy( const, schema=schema, target_table=self.table ) else: # "target_table" for ForeignKeyConstraint.copy() is # only used if the FK is detected as being # self-referential, which we are handling above. const_copy = _copy(const, schema=schema) else: const_copy = _copy( const, schema=schema, target_table=new_table ) if isinstance(const, ForeignKeyConstraint): self._setup_referent(m, const) new_table.append_constraint(const_copy) def _gather_indexes_from_both_tables(self) -> List[Index]: assert self.new_table is not None idx: List[Index] = [] for idx_existing in self.indexes.values(): # this is a lift-and-move from Table.to_metadata if idx_existing._column_flag: # type: ignore continue idx_copy = Index( idx_existing.name, unique=idx_existing.unique, *[ _copy_expression(expr, self.new_table) for expr in _idx_table_bound_expressions(idx_existing) ], _table=self.new_table, **idx_existing.kwargs, ) idx.append(idx_copy) for index in self.new_indexes.values(): idx.append( Index( index.name, unique=index.unique, *[self.new_table.c[col] for col in index.columns.keys()], **index.kwargs, ) ) return idx def _setup_referent( self, metadata: MetaData, constraint: ForeignKeyConstraint ) -> None: spec = constraint.elements[ 0 ]._get_colspec() # type:ignore[attr-defined] parts = spec.split(".") tname = parts[-2] if len(parts) == 3: referent_schema = parts[0] else: referent_schema = None if tname != self.temp_table_name: key = sql_schema._get_table_key(tname, referent_schema) def colspec(elem: Any): return elem._get_colspec() if key in metadata.tables: t = metadata.tables[key] for elem in constraint.elements: colname = colspec(elem).split(".")[-1] if colname not in t.c: t.append_column(Column(colname, sqltypes.NULLTYPE)) else: Table( tname, metadata, *[ Column(n, sqltypes.NULLTYPE) for n in [ colspec(elem).split(".")[-1] for elem in constraint.elements ] ], schema=referent_schema, ) def _create(self, op_impl: DefaultImpl) -> None: self._transfer_elements_to_new_table() op_impl.prep_table_for_batch(self, self.table) assert self.new_table is not None op_impl.create_table(self.new_table) try: op_impl._exec( _insert_inline(self.new_table).from_select( list( k for k, transfer in self.column_transfers.items() if "expr" in transfer ), _select( *[ transfer["expr"] for transfer in self.column_transfers.values() if "expr" in transfer ] ), ) ) op_impl.drop_table(self.table) except: op_impl.drop_table(self.new_table) raise else: op_impl.rename_table( self.temp_table_name, self.table.name, schema=self.table.schema ) self.new_table.name = self.table.name try: for idx in self._gather_indexes_from_both_tables(): op_impl.create_index(idx) finally: self.new_table.name = self.temp_table_name def alter_column( self, table_name: str, column_name: str, nullable: Optional[bool] = None, server_default: Optional[Union[Function[Any], str, bool]] = False, name: Optional[str] = None, type_: Optional[TypeEngine] = None, autoincrement: Optional[Union[bool, Literal["auto"]]] = None, comment: Union[str, Literal[False]] = False, **kw, ) -> None: existing = self.columns[column_name] existing_transfer: Dict[str, Any] = self.column_transfers[column_name] if name is not None and name != column_name: # note that we don't change '.key' - we keep referring # to the renamed column by its old key in _create(). neat! existing.name = name existing_transfer["name"] = name existing_type = kw.get("existing_type", None) if existing_type: resolved_existing_type = _resolve_for_variant( kw["existing_type"], self.impl.dialect ) # pop named constraints for Boolean/Enum for rename if ( isinstance(resolved_existing_type, SchemaEventTarget) and resolved_existing_type.name # type:ignore[attr-defined] # noqa E501 ): self.named_constraints.pop( resolved_existing_type.name, # type:ignore[attr-defined] # noqa E501 None, ) if type_ is not None: type_ = sqltypes.to_instance(type_) # old type is being discarded so turn off eventing # rules. Alternatively we can # erase the events set up by this type, but this is simpler. # we also ignore the drop_constraint that will come here from # Operations.implementation_for(alter_column) if isinstance(existing.type, SchemaEventTarget): existing.type._create_events = ( # type:ignore[attr-defined] existing.type.create_constraint # type:ignore[attr-defined] # noqa ) = False self.impl.cast_for_batch_migrate( existing, existing_transfer, type_ ) existing.type = type_ # we *dont* however set events for the new type, because # alter_column is invoked from # Operations.implementation_for(alter_column) which already # will emit an add_constraint() if nullable is not None: existing.nullable = nullable if server_default is not False: if server_default is None: existing.server_default = None else: sql_schema.DefaultClause( server_default # type: ignore[arg-type] )._set_parent( # type:ignore[attr-defined] existing ) if autoincrement is not None: existing.autoincrement = bool(autoincrement) if comment is not False: existing.comment = comment def _setup_dependencies_for_add_column( self, colname: str, insert_before: Optional[str], insert_after: Optional[str], ) -> None: index_cols = self.existing_ordering col_indexes = {name: i for i, name in enumerate(index_cols)} if not self.partial_reordering: if insert_after: if not insert_before: if insert_after in col_indexes: # insert after an existing column idx = col_indexes[insert_after] + 1 if idx < len(index_cols): insert_before = index_cols[idx] else: # insert after a column that is also new insert_before = dict(self.add_col_ordering)[ insert_after ] if insert_before: if not insert_after: if insert_before in col_indexes: # insert before an existing column idx = col_indexes[insert_before] - 1 if idx >= 0: insert_after = index_cols[idx] else: # insert before a column that is also new insert_after = { b: a for a, b in self.add_col_ordering }[insert_before] if insert_before: self.add_col_ordering += ((colname, insert_before),) if insert_after: self.add_col_ordering += ((insert_after, colname),) if ( not self.partial_reordering and not insert_before and not insert_after and col_indexes ): self.add_col_ordering += ((index_cols[-1], colname),) def add_column( self, table_name: str, column: Column[Any], insert_before: Optional[str] = None, insert_after: Optional[str] = None, **kw, ) -> None: self._setup_dependencies_for_add_column( column.name, insert_before, insert_after ) # we copy the column because operations.add_column() # gives us a Column that is part of a Table already. self.columns[column.name] = _copy(column, schema=self.table.schema) self.column_transfers[column.name] = {} def drop_column( self, table_name: str, column: Union[ColumnClause[Any], Column[Any]], **kw, ) -> None: if column.name in self.table.primary_key.columns: _remove_column_from_collection( self.table.primary_key.columns, column ) del self.columns[column.name] del self.column_transfers[column.name] self.existing_ordering.remove(column.name) # pop named constraints for Boolean/Enum for rename if ( "existing_type" in kw and isinstance(kw["existing_type"], SchemaEventTarget) and kw["existing_type"].name # type:ignore[attr-defined] ): self.named_constraints.pop( kw["existing_type"].name, None # type:ignore[attr-defined] ) def create_column_comment(self, column): """the batch table creation function will issue create_column_comment on the real "impl" as part of the create table process. That is, the Column object will have the comment on it already, so when it is received by add_column() it will be a normal part of the CREATE TABLE and doesn't need an extra step here. """ def create_table_comment(self, table): """the batch table creation function will issue create_table_comment on the real "impl" as part of the create table process. """ def drop_table_comment(self, table): """the batch table creation function will issue drop_table_comment on the real "impl" as part of the create table process. """ def add_constraint(self, const: Constraint) -> None: if not constraint_name_defined(const.name): raise ValueError("Constraint must have a name") if isinstance(const, sql_schema.PrimaryKeyConstraint): if self.table.primary_key in self.unnamed_constraints: self.unnamed_constraints.remove(self.table.primary_key) if constraint_name_string(const.name): self.named_constraints[const.name] = const else: self.unnamed_constraints.append(const) def drop_constraint(self, const: Constraint) -> None: if not const.name: raise ValueError("Constraint must have a name") try: if const.name in self.col_named_constraints: col, const = self.col_named_constraints.pop(const.name) for col_const in list(self.columns[col.name].constraints): if col_const.name == const.name: self.columns[col.name].constraints.remove(col_const) elif constraint_name_string(const.name): const = self.named_constraints.pop(const.name) elif const in self.unnamed_constraints: self.unnamed_constraints.remove(const) except KeyError: if _is_type_bound(const): # type-bound constraints are only included in the new # table via their type object in any case, so ignore the # drop_constraint() that comes here via the # Operations.implementation_for(alter_column) return raise ValueError("No such constraint: '%s'" % const.name) else: if isinstance(const, PrimaryKeyConstraint): for col in const.columns: self.columns[col.name].primary_key = False def create_index(self, idx: Index) -> None: self.new_indexes[idx.name] = idx # type: ignore[index] def drop_index(self, idx: Index) -> None: try: del self.indexes[idx.name] # type: ignore[arg-type] except KeyError: raise ValueError("No such index: '%s'" % idx.name) def rename_table(self, *arg, **kw): raise NotImplementedError("TODO")