antoine-lizee
commented
7 years ago For you information, I ended up massively monkey-patching the flask version of the VersioningManager to issue the actual tooling & auditing statements on 'after_configured' instead of binding them to 'after_create' table listeners that never got fired. Here is how it goes:
import sqlalchemy as sa
from postgresql_audit import ImproperlyConfigured
from postgresql_audit.base import array, StatementExecutor
from postgresql_audit.flask import VersioningManager as BaseVersioningManager, context_available
from sqlalchemy.exc import ProgrammingError
from app import db
class MigratedVersioningManager(BaseVersioningManager):
def audit_table(self, table, exclude_columns=None):
""" Issues SQL to audit a table.
This is a near-complete copy of the corresponding super() function, but actually firing the events instead of
binding them to uncalled 'after_create' listeners.
This function is itself called when the 'after_configured' is fired, calling `configure_versioned_classes()` as
per the `postgresql_audit.VersionManager.listeners`
"""
args = [table.name]
if exclude_columns:
for column in exclude_columns:
if column not in table.c:
raise ImproperlyConfigured(
"Could not configure versioning. Table '{}'' does "
"not have a column named '{}'.".format(
table.name, column
)
)
args.append(array(exclude_columns))
if self.schema_name is None:
func = sa.func.audit_table
else:
func = getattr(getattr(sa.func, self.schema_name), 'audit_table')
query = sa.select([func(*args)])
executor = StatementExecutor(query)
self.fire_event(executor)
def fire_event(self, event):
with db.engine.begin() as connection:
if isinstance(event, sa.schema.DDL):
connection.execute(event)
else:
event('dummy_table_argument', connection)
def fire_table_listeners(self):
table_listener_events = [l[1] for l in self.table_listeners['activity']] + \
[l[1] for l in self.table_listeners['transaction']]
for event in table_listener_events:
self.fire_event(event)
def configure_versioned_classes(self):
""" Fire the tooling building requests + configures the audited classes
This is bound to the 'after_configured' listener.
"""
try:
self.fire_table_listeners()
super().configure_versioned_classes()
except ProgrammingError:
print("Aborting auditing setup because tables are inexistent yet. Try again after migrating the database to"
"create the missing tables.")
def attach_listeners(self):
""" Monkey-patched from super() to not attache the table listeners.
"""
for listener in self.listeners:
sa.event.listen(*listener)
karl-dv
zwerg44
If I understand well, the
table_listenersthat put the tooling in place as well as the individualaudit_tablelisteners that enable auditing for a single table are fired on an 'after_create' bound to a table instance.This seems to work only when directly using the mapper constructors like
create_all(), because it uses the objects as defined, whereas using alembic migrations will lose track of the objects to which the listener is bound when creating the tables, preventing it to be ever fired. (see http://stackoverflow.com/a/16907683/1877609)It would be amazing to have some kind of interface to either (i) easily generate migrations that would basically do the job of the listeners (ii) fire the listeners' content at will.
[This issue is related to #7]
Any thought on that?