alembic_pg_autogen.diff

Diff logic for comparing canonical catalog snapshots.

Module Contents

Classes

Action	The kind of operation needed to reconcile current state with desired state.
FunctionOp	A single diff operation on a PostgreSQL function.
TriggerOp	A single diff operation on a PostgreSQL trigger.
ViewOp	A single diff operation on a PostgreSQL view.
DiffResult	Result of comparing two canonical catalog snapshots.

Functions

diff	Compare two canonical catalog snapshots and produce diff operations.
_diff_items	Diff two sequences of catalog items by identity key (all fields except the last definition field).

Data

log
_InfoT
_OpT

API

alembic_pg_autogen.diff.log = 'getLogger(...)'

class alembic_pg_autogen.diff.Action(*args, **kwds)

Bases: enum.Enum

The kind of operation needed to reconcile current state with desired state.

Initialization

CREATE = 'create'

REPLACE = 'replace'

DROP = 'drop'

class alembic_pg_autogen.diff.FunctionOp

Bases: typing.NamedTuple

A single diff operation on a PostgreSQL function.

action: alembic_pg_autogen.diff.Action = None

current: alembic_pg_autogen.inspect.FunctionInfo | None = None

desired: alembic_pg_autogen.inspect.FunctionInfo | None = None

class alembic_pg_autogen.diff.TriggerOp

Bases: typing.NamedTuple

A single diff operation on a PostgreSQL trigger.

action: alembic_pg_autogen.diff.Action = None

current: alembic_pg_autogen.inspect.TriggerInfo | None = None

desired: alembic_pg_autogen.inspect.TriggerInfo | None = None

class alembic_pg_autogen.diff.ViewOp

Bases: typing.NamedTuple

A single diff operation on a PostgreSQL view.

action: alembic_pg_autogen.diff.Action = None

current: alembic_pg_autogen.inspect.ViewInfo | None = None

desired: alembic_pg_autogen.inspect.ViewInfo | None = None

class alembic_pg_autogen.diff.DiffResult

Bases: typing.NamedTuple

Result of comparing two canonical catalog snapshots.

function_ops: collections.abc.Sequence[alembic_pg_autogen.diff.FunctionOp] = None

trigger_ops: collections.abc.Sequence[alembic_pg_autogen.diff.TriggerOp] = None

view_ops: collections.abc.Sequence[alembic_pg_autogen.diff.ViewOp] = ()

alembic_pg_autogen.diff._InfoT = 'TypeVar(...)'

alembic_pg_autogen.diff._OpT = 'TypeVar(...)'

alembic_pg_autogen.diff.diff(current: alembic_pg_autogen.canonicalize.CanonicalState, desired: alembic_pg_autogen.canonicalize.CanonicalState) → alembic_pg_autogen.diff.DiffResult

Compare two canonical catalog snapshots and produce diff operations.

Matches functions by (schema, name, identity_args), triggers by (schema, table_name, trigger_name), and views by (schema, name). Objects present only in desired produce CREATE ops, objects only in current produce DROP ops, and objects in both with differing definitions produce REPLACE ops.

Args:

current: The current database state (from inspection). desired: The desired state (from canonicalization).

Returns:

A DiffResult with sorted sequences of function, trigger, and view ops.

alembic_pg_autogen.diff._diff_items(current_items: collections.abc.Sequence[alembic_pg_autogen.diff._InfoT], desired_items: collections.abc.Sequence[alembic_pg_autogen.diff._InfoT], make_op: collections.abc.Callable[[alembic_pg_autogen.diff.Action, alembic_pg_autogen.diff._InfoT | None, alembic_pg_autogen.diff._InfoT | None], alembic_pg_autogen.diff._OpT]) → list[alembic_pg_autogen.diff._OpT]

Diff two sequences of catalog items by identity key (all fields except the last definition field).