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from __future__ import annotations
import logging
import re
from typing import Any
from typing import cast
from typing import List
from typing import Optional
from typing import Sequence
from typing import Tuple
from typing import TYPE_CHECKING
from typing import Union
from sqlalchemy import Column
from sqlalchemy import Index
from sqlalchemy import literal_column
from sqlalchemy import Numeric
from sqlalchemy import text
from sqlalchemy import types as sqltypes
from sqlalchemy.dialects.postgresql import BIGINT
from sqlalchemy.dialects.postgresql import ExcludeConstraint
from sqlalchemy.dialects.postgresql import INTEGER
from sqlalchemy.schema import CreateIndex
from sqlalchemy.sql import operators
from sqlalchemy.sql.elements import ColumnClause
from sqlalchemy.sql.elements import TextClause
from sqlalchemy.sql.elements import UnaryExpression
from sqlalchemy.sql.functions import FunctionElement
from sqlalchemy.types import NULLTYPE
from .base import alter_column
from .base import alter_table
from .base import AlterColumn
from .base import ColumnComment
from .base import compiles
from .base import format_column_name
from .base import format_table_name
from .base import format_type
from .base import IdentityColumnDefault
from .base import RenameTable
from .impl import DefaultImpl
from .. import util
from ..autogenerate import render
from ..operations import ops
from ..operations import schemaobj
from ..operations.base import BatchOperations
from ..operations.base import Operations
from ..util import sqla_compat
if TYPE_CHECKING:
from typing import Literal
from sqlalchemy.dialects.postgresql.array import ARRAY
from sqlalchemy.dialects.postgresql.base import PGDDLCompiler
from sqlalchemy.dialects.postgresql.hstore import HSTORE
from sqlalchemy.dialects.postgresql.json import JSON
from sqlalchemy.dialects.postgresql.json import JSONB
from sqlalchemy.sql.elements import BinaryExpression
from sqlalchemy.sql.elements import ClauseElement
from sqlalchemy.sql.elements import quoted_name
from sqlalchemy.sql.schema import MetaData
from sqlalchemy.sql.schema import Table
from sqlalchemy.sql.type_api import TypeEngine
from .base import _ServerDefault
from ..autogenerate.api import AutogenContext
from ..autogenerate.render import _f_name
from ..runtime.migration import MigrationContext
log = logging.getLogger(__name__)
class PostgresqlImpl(DefaultImpl):
__dialect__ = "postgresql"
transactional_ddl = True
type_synonyms = DefaultImpl.type_synonyms + (
{"FLOAT", "DOUBLE PRECISION"},
)
identity_attrs_ignore = ("on_null", "order")
def create_index(self, index):
# this likely defaults to None if not present, so get()
# should normally not return the default value. being
# defensive in any case
postgresql_include = index.kwargs.get("postgresql_include", None) or ()
for col in postgresql_include:
if col not in index.table.c:
index.table.append_column(Column(col, sqltypes.NullType))
self._exec(CreateIndex(index))
def prep_table_for_batch(self, batch_impl, table):
for constraint in table.constraints:
if (
constraint.name is not None
and constraint.name in batch_impl.named_constraints
):
self.drop_constraint(constraint)
def compare_server_default(
self,
inspector_column,
metadata_column,
rendered_metadata_default,
rendered_inspector_default,
):
# don't do defaults for SERIAL columns
if (
metadata_column.primary_key
and metadata_column is metadata_column.table._autoincrement_column
):
return False
conn_col_default = rendered_inspector_default
defaults_equal = conn_col_default == rendered_metadata_default
if defaults_equal:
return False
if None in (
conn_col_default,
rendered_metadata_default,
metadata_column.server_default,
):
return not defaults_equal
metadata_default = metadata_column.server_default.arg
if isinstance(metadata_default, str):
if not isinstance(inspector_column.type, Numeric):
metadata_default = re.sub(r"^'|'$", "", metadata_default)
metadata_default = f"'{metadata_default}'"
metadata_default = literal_column(metadata_default)
# run a real compare against the server
return not self.connection.scalar(
sqla_compat._select(
literal_column(conn_col_default) == metadata_default
)
)
def alter_column( # type:ignore[override]
self,
table_name: str,
column_name: str,
nullable: Optional[bool] = None,
server_default: Union[_ServerDefault, Literal[False]] = False,
name: Optional[str] = None,
type_: Optional[TypeEngine] = None,
schema: Optional[str] = None,
autoincrement: Optional[bool] = None,
existing_type: Optional[TypeEngine] = None,
existing_server_default: Optional[_ServerDefault] = None,
existing_nullable: Optional[bool] = None,
existing_autoincrement: Optional[bool] = None,
**kw: Any,
) -> None:
using = kw.pop("postgresql_using", None)
if using is not None and type_ is None:
raise util.CommandError(
"postgresql_using must be used with the type_ parameter"
)
if type_ is not None:
self._exec(
PostgresqlColumnType(
table_name,
column_name,
type_,
schema=schema,
using=using,
existing_type=existing_type,
existing_server_default=existing_server_default,
existing_nullable=existing_nullable,
)
)
super().alter_column(
table_name,
column_name,
nullable=nullable,
server_default=server_default,
name=name,
schema=schema,
autoincrement=autoincrement,
existing_type=existing_type,
existing_server_default=existing_server_default,
existing_nullable=existing_nullable,
existing_autoincrement=existing_autoincrement,
**kw,
)
def autogen_column_reflect(self, inspector, table, column_info):
if column_info.get("default") and isinstance(
column_info["type"], (INTEGER, BIGINT)
):
seq_match = re.match(
r"nextval\('(.+?)'::regclass\)", column_info["default"]
)
if seq_match:
info = sqla_compat._exec_on_inspector(
inspector,
text(
"select c.relname, a.attname "
"from pg_class as c join "
"pg_depend d on d.objid=c.oid and "
"d.classid='pg_class'::regclass and "
"d.refclassid='pg_class'::regclass "
"join pg_class t on t.oid=d.refobjid "
"join pg_attribute a on a.attrelid=t.oid and "
"a.attnum=d.refobjsubid "
"where c.relkind='S' and c.relname=:seqname"
),
seqname=seq_match.group(1),
).first()
if info:
seqname, colname = info
if colname == column_info["name"]:
log.info(
"Detected sequence named '%s' as "
"owned by integer column '%s(%s)', "
"assuming SERIAL and omitting",
seqname,
table.name,
colname,
)
# sequence, and the owner is this column,
# its a SERIAL - whack it!
del column_info["default"]
def correct_for_autogen_constraints(
self,
conn_unique_constraints,
conn_indexes,
metadata_unique_constraints,
metadata_indexes,
):
doubled_constraints = {
index
for index in conn_indexes
if index.info.get("duplicates_constraint")
}
for ix in doubled_constraints:
conn_indexes.remove(ix)
if not sqla_compat.sqla_2:
self._skip_functional_indexes(metadata_indexes, conn_indexes)
def _cleanup_index_expr(
self, index: Index, expr: str, remove_suffix: str
) -> str:
# start = expr
expr = expr.lower()
expr = expr.replace('"', "")
if index.table is not None:
# should not be needed, since include_table=False is in compile
expr = expr.replace(f"{index.table.name.lower()}.", "")
while expr and expr[0] == "(" and expr[-1] == ")":
expr = expr[1:-1]
if "::" in expr:
# strip :: cast. types can have spaces in them
expr = re.sub(r"(::[\w ]+\w)", "", expr)
if remove_suffix and expr.endswith(remove_suffix):
expr = expr[: -len(remove_suffix)]
# print(f"START: {start} END: {expr}")
return expr
def _default_modifiers(self, exp: ClauseElement) -> str:
to_remove = ""
while isinstance(exp, UnaryExpression):
if exp.modifier is None:
exp = exp.element
else:
op = exp.modifier
if isinstance(exp.element, UnaryExpression):
inner_op = exp.element.modifier
else:
inner_op = None
if inner_op is None:
if op == operators.asc_op:
# default is asc
to_remove = " asc"
elif op == operators.nullslast_op:
# default is nulls last
to_remove = " nulls last"
else:
if (
inner_op == operators.asc_op
and op == operators.nullslast_op
):
# default is asc nulls last
to_remove = " asc nulls last"
elif (
inner_op == operators.desc_op
and op == operators.nullsfirst_op
):
# default for desc is nulls first
to_remove = " nulls first"
break
return to_remove
def create_index_sig(self, index: Index) -> Tuple[Any, ...]:
return tuple(
self._cleanup_index_expr(
index,
*(
(e, "")
if isinstance(e, str)
else (self._compile_element(e), self._default_modifiers(e))
),
)
for e in index.expressions
)
def _compile_element(self, element: ClauseElement) -> str:
return element.compile(
dialect=self.dialect,
compile_kwargs={"literal_binds": True, "include_table": False},
).string
def render_type(
self, type_: TypeEngine, autogen_context: AutogenContext
) -> Union[str, Literal[False]]:
mod = type(type_).__module__
if not mod.startswith("sqlalchemy.dialects.postgresql"):
return False
if hasattr(self, "_render_%s_type" % type_.__visit_name__):
meth = getattr(self, "_render_%s_type" % type_.__visit_name__)
return meth(type_, autogen_context)
return False
def _render_HSTORE_type(
self, type_: HSTORE, autogen_context: AutogenContext
) -> str:
return cast(
str,
render._render_type_w_subtype(
type_, autogen_context, "text_type", r"(.+?\(.*text_type=)"
),
)
def _render_ARRAY_type(
self, type_: ARRAY, autogen_context: AutogenContext
) -> str:
return cast(
str,
render._render_type_w_subtype(
type_, autogen_context, "item_type", r"(.+?\()"
),
)
def _render_JSON_type(
self, type_: JSON, autogen_context: AutogenContext
) -> str:
return cast(
str,
render._render_type_w_subtype(
type_, autogen_context, "astext_type", r"(.+?\(.*astext_type=)"
),
)
def _render_JSONB_type(
self, type_: JSONB, autogen_context: AutogenContext
) -> str:
return cast(
str,
render._render_type_w_subtype(
type_, autogen_context, "astext_type", r"(.+?\(.*astext_type=)"
),
)
class PostgresqlColumnType(AlterColumn):
def __init__(
self, name: str, column_name: str, type_: TypeEngine, **kw
) -> None:
using = kw.pop("using", None)
super().__init__(name, column_name, **kw)
self.type_ = sqltypes.to_instance(type_)
self.using = using
@compiles(RenameTable, "postgresql")
def visit_rename_table(
element: RenameTable, compiler: PGDDLCompiler, **kw
) -> str:
return "%s RENAME TO %s" % (
alter_table(compiler, element.table_name, element.schema),
format_table_name(compiler, element.new_table_name, None),
)
@compiles(PostgresqlColumnType, "postgresql")
def visit_column_type(
element: PostgresqlColumnType, compiler: PGDDLCompiler, **kw
) -> str:
return "%s %s %s %s" % (
alter_table(compiler, element.table_name, element.schema),
alter_column(compiler, element.column_name),
"TYPE %s" % format_type(compiler, element.type_),
"USING %s" % element.using if element.using else "",
)
@compiles(ColumnComment, "postgresql")
def visit_column_comment(
element: ColumnComment, compiler: PGDDLCompiler, **kw
) -> str:
ddl = "COMMENT ON COLUMN {table_name}.{column_name} IS {comment}"
comment = (
compiler.sql_compiler.render_literal_value(
element.comment, sqltypes.String()
)
if element.comment is not None
else "NULL"
)
return ddl.format(
table_name=format_table_name(
compiler, element.table_name, element.schema
),
column_name=format_column_name(compiler, element.column_name),
comment=comment,
)
@compiles(IdentityColumnDefault, "postgresql")
def visit_identity_column(
element: IdentityColumnDefault, compiler: PGDDLCompiler, **kw
):
text = "%s %s " % (
alter_table(compiler, element.table_name, element.schema),
alter_column(compiler, element.column_name),
)
if element.default is None:
# drop identity
text += "DROP IDENTITY"
return text
elif element.existing_server_default is None:
# add identity options
text += "ADD "
text += compiler.visit_identity_column(element.default)
return text
else:
# alter identity
diff, _, _ = element.impl._compare_identity_default(
element.default, element.existing_server_default
)
identity = element.default
for attr in sorted(diff):
if attr == "always":
text += "SET GENERATED %s " % (
"ALWAYS" if identity.always else "BY DEFAULT"
)
else:
text += "SET %s " % compiler.get_identity_options(
sqla_compat.Identity(**{attr: getattr(identity, attr)})
)
return text
@Operations.register_operation("create_exclude_constraint")
@BatchOperations.register_operation(
"create_exclude_constraint", "batch_create_exclude_constraint"
)
@ops.AddConstraintOp.register_add_constraint("exclude_constraint")
class CreateExcludeConstraintOp(ops.AddConstraintOp):
"""Represent a create exclude constraint operation."""
constraint_type = "exclude"
def __init__(
self,
constraint_name: sqla_compat._ConstraintName,
table_name: Union[str, quoted_name],
elements: Union[
Sequence[Tuple[str, str]],
Sequence[Tuple[ColumnClause[Any], str]],
],
where: Optional[Union[BinaryExpression, str]] = None,
schema: Optional[str] = None,
_orig_constraint: Optional[ExcludeConstraint] = None,
**kw,
) -> None:
self.constraint_name = constraint_name
self.table_name = table_name
self.elements = elements
self.where = where
self.schema = schema
self._orig_constraint = _orig_constraint
self.kw = kw
@classmethod
def from_constraint( # type:ignore[override]
cls, constraint: ExcludeConstraint
) -> CreateExcludeConstraintOp:
constraint_table = sqla_compat._table_for_constraint(constraint)
return cls(
constraint.name,
constraint_table.name,
[
(expr, op)
for expr, name, op in constraint._render_exprs # type:ignore[attr-defined] # noqa
],
where=cast(
"Optional[Union[BinaryExpression, str]]", constraint.where
),
schema=constraint_table.schema,
_orig_constraint=constraint,
deferrable=constraint.deferrable,
initially=constraint.initially,
using=constraint.using,
)
def to_constraint(
self, migration_context: Optional[MigrationContext] = None
) -> ExcludeConstraint:
if self._orig_constraint is not None:
return self._orig_constraint
schema_obj = schemaobj.SchemaObjects(migration_context)
t = schema_obj.table(self.table_name, schema=self.schema)
excl = ExcludeConstraint(
*self.elements,
name=self.constraint_name,
where=self.where,
**self.kw,
)
for (
expr,
name,
oper,
) in excl._render_exprs: # type:ignore[attr-defined]
t.append_column(Column(name, NULLTYPE))
t.append_constraint(excl)
return excl
@classmethod
def create_exclude_constraint(
cls,
operations: Operations,
constraint_name: str,
table_name: str,
*elements: Any,
**kw: Any,
) -> Optional[Table]:
"""Issue an alter to create an EXCLUDE constraint using the
current migration context.
.. note:: This method is Postgresql specific, and additionally
requires at least SQLAlchemy 1.0.
e.g.::
from alembic import op
op.create_exclude_constraint(
"user_excl",
"user",
("period", "&&"),
("group", "="),
where=("group != 'some group'"),
)
Note that the expressions work the same way as that of
the ``ExcludeConstraint`` object itself; if plain strings are
passed, quoting rules must be applied manually.
:param name: Name of the constraint.
:param table_name: String name of the source table.
:param elements: exclude conditions.
:param where: SQL expression or SQL string with optional WHERE
clause.
:param deferrable: optional bool. If set, emit DEFERRABLE or
NOT DEFERRABLE when issuing DDL for this constraint.
:param initially: optional string. If set, emit INITIALLY <value>
when issuing DDL for this constraint.
:param schema: Optional schema name to operate within.
"""
op = cls(constraint_name, table_name, elements, **kw)
return operations.invoke(op)
@classmethod
def batch_create_exclude_constraint(
cls,
operations: BatchOperations,
constraint_name: str,
*elements: Any,
**kw: Any,
):
"""Issue a "create exclude constraint" instruction using the
current batch migration context.
.. note:: This method is Postgresql specific, and additionally
requires at least SQLAlchemy 1.0.
.. seealso::
:meth:`.Operations.create_exclude_constraint`
"""
kw["schema"] = operations.impl.schema
op = cls(constraint_name, operations.impl.table_name, elements, **kw)
return operations.invoke(op)
@render.renderers.dispatch_for(CreateExcludeConstraintOp)
def _add_exclude_constraint(
autogen_context: AutogenContext, op: CreateExcludeConstraintOp
) -> str:
return _exclude_constraint(op.to_constraint(), autogen_context, alter=True)
@render._constraint_renderers.dispatch_for(ExcludeConstraint)
def _render_inline_exclude_constraint(
constraint: ExcludeConstraint,
autogen_context: AutogenContext,
namespace_metadata: MetaData,
) -> str:
rendered = render._user_defined_render(
"exclude", constraint, autogen_context
)
if rendered is not False:
return rendered
return _exclude_constraint(constraint, autogen_context, False)
def _postgresql_autogenerate_prefix(autogen_context: AutogenContext) -> str:
imports = autogen_context.imports
if imports is not None:
imports.add("from sqlalchemy.dialects import postgresql")
return "postgresql."
def _exclude_constraint(
constraint: ExcludeConstraint,
autogen_context: AutogenContext,
alter: bool,
) -> str:
opts: List[Tuple[str, Union[quoted_name, str, _f_name, None]]] = []
has_batch = autogen_context._has_batch
if constraint.deferrable:
opts.append(("deferrable", str(constraint.deferrable)))
if constraint.initially:
opts.append(("initially", str(constraint.initially)))
if constraint.using:
opts.append(("using", str(constraint.using)))
if not has_batch and alter and constraint.table.schema:
opts.append(("schema", render._ident(constraint.table.schema)))
if not alter and constraint.name:
opts.append(
("name", render._render_gen_name(autogen_context, constraint.name))
)
def do_expr_where_opts():
args = [
"(%s, %r)"
% (
_render_potential_column(sqltext, autogen_context),
opstring,
)
for sqltext, name, opstring in constraint._render_exprs # type:ignore[attr-defined] # noqa
]
if constraint.where is not None:
args.append(
"where=%s"
% render._render_potential_expr(
constraint.where, autogen_context
)
)
args.extend(["%s=%r" % (k, v) for k, v in opts])
return args
if alter:
args = [
repr(render._render_gen_name(autogen_context, constraint.name))
]
if not has_batch:
args += [repr(render._ident(constraint.table.name))]
args.extend(do_expr_where_opts())
return "%(prefix)screate_exclude_constraint(%(args)s)" % {
"prefix": render._alembic_autogenerate_prefix(autogen_context),
"args": ", ".join(args),
}
else:
args = do_expr_where_opts()
return "%(prefix)sExcludeConstraint(%(args)s)" % {
"prefix": _postgresql_autogenerate_prefix(autogen_context),
"args": ", ".join(args),
}
def _render_potential_column(
value: Union[
ColumnClause[Any], Column[Any], TextClause, FunctionElement[Any]
],
autogen_context: AutogenContext,
) -> str:
if isinstance(value, ColumnClause):
if value.is_literal:
# like literal_column("int8range(from, to)") in ExcludeConstraint
template = "%(prefix)sliteral_column(%(name)r)"
else:
template = "%(prefix)scolumn(%(name)r)"
return template % {
"prefix": render._sqlalchemy_autogenerate_prefix(autogen_context),
"name": value.name,
}
else:
return render._render_potential_expr(
value,
autogen_context,
wrap_in_text=isinstance(value, (TextClause, FunctionElement)),
)
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