Trying to replacing SQLAlchemy-Continuum

I’m trying to replace SQLAlchemy-Continuum in my project with postgresql-audit but must be missing something.

When I replace the call to make_versioned with versioning_manager.init(Base) and try and create the schema it tries to use the audit_table function before it’s defined.

Traceback (most recent call last):
  File "/Users/dereklambert/Development/audit-tools3/venv/lib/python3.6/site-packages/sqlalchemy/engine/base.py", line 1193, in _execute_context
    context)
  File "/Users/dereklambert/Development/audit-tools3/venv/lib/python3.6/site-packages/sqlalchemy/engine/default.py", line 507, in do_execute
    cursor.execute(statement, parameters)
psycopg2.ProgrammingError: function audit_table(unknown) does not exist
LINE 1: SELECT audit_table('company') AS audit_table_1
               ^
HINT:  No function matches the given name and argument types. You might need to add explicit type casts.


The above exception was the direct cause of the following exception:

Traceback (most recent call last):
  File "populate.py", line 30, in <module>
    database_manager.create_schema()
  File "/Users/dereklambert/Development/audit-tools3/audit_tools/manager/database_manager.py", line 88, in create_schema
    Base.metadata.create_all(self.engine)
  File "/Users/dereklambert/Development/audit-tools3/venv/lib/python3.6/site-packages/sqlalchemy/sql/schema.py", line 4004, in create_all
    tables=tables)
  File "/Users/dereklambert/Development/audit-tools3/venv/lib/python3.6/site-packages/sqlalchemy/engine/base.py", line 1940, in _run_visitor
    conn._run_visitor(visitorcallable, element, **kwargs)
  File "/Users/dereklambert/Development/audit-tools3/venv/lib/python3.6/site-packages/sqlalchemy/engine/base.py", line 1549, in _run_visitor
    **kwargs).traverse_single(element)
  File "/Users/dereklambert/Development/audit-tools3/venv/lib/python3.6/site-packages/sqlalchemy/sql/visitors.py", line 121, in traverse_single
    return meth(obj, **kw)
  File "/Users/dereklambert/Development/audit-tools3/venv/lib/python3.6/site-packages/sqlalchemy/sql/ddl.py", line 757, in visit_metadata
    _is_metadata_operation=True)
  File "/Users/dereklambert/Development/audit-tools3/venv/lib/python3.6/site-packages/sqlalchemy/sql/visitors.py", line 121, in traverse_single
    return meth(obj, **kw)
  File "/Users/dereklambert/Development/audit-tools3/venv/lib/python3.6/site-packages/sqlalchemy/sql/ddl.py", line 810, in visit_table
    _is_metadata_operation=_is_metadata_operation)
  File "/Users/dereklambert/Development/audit-tools3/venv/lib/python3.6/site-packages/sqlalchemy/event/attr.py", line 284, in __call__
    fn(*args, **kw)
  File "/Users/dereklambert/Development/audit-tools3/venv/lib/python3.6/site-packages/postgresql_audit/base.py", line 33, in __call__
    bind.execute(self.stmt)
  File "/Users/dereklambert/Development/audit-tools3/venv/lib/python3.6/site-packages/sqlalchemy/engine/base.py", line 948, in execute
    return meth(self, multiparams, params)
  File "/Users/dereklambert/Development/audit-tools3/venv/lib/python3.6/site-packages/sqlalchemy/sql/elements.py", line 269, in _execute_on_connection
    return connection._execute_clauseelement(self, multiparams, params)
  File "/Users/dereklambert/Development/audit-tools3/venv/lib/python3.6/site-packages/sqlalchemy/engine/base.py", line 1060, in _execute_clauseelement
    compiled_sql, distilled_params
  File "/Users/dereklambert/Development/audit-tools3/venv/lib/python3.6/site-packages/sqlalchemy/engine/base.py", line 1200, in _execute_context
    context)
  File "/Users/dereklambert/Development/audit-tools3/venv/lib/python3.6/site-packages/sqlalchemy/engine/base.py", line 1413, in _handle_dbapi_exception
    exc_info
  File "/Users/dereklambert/Development/audit-tools3/venv/lib/python3.6/site-packages/sqlalchemy/util/compat.py", line 203, in raise_from_cause
    reraise(type(exception), exception, tb=exc_tb, cause=cause)
  File "/Users/dereklambert/Development/audit-tools3/venv/lib/python3.6/site-packages/sqlalchemy/util/compat.py", line 186, in reraise
    raise value.with_traceback(tb)
  File "/Users/dereklambert/Development/audit-tools3/venv/lib/python3.6/site-packages/sqlalchemy/engine/base.py", line 1193, in _execute_context
    context)
  File "/Users/dereklambert/Development/audit-tools3/venv/lib/python3.6/site-packages/sqlalchemy/engine/default.py", line 507, in do_execute
    cursor.execute(statement, parameters)
sqlalchemy.exc.ProgrammingError: (psycopg2.ProgrammingError) function audit_table(unknown) does not exist
LINE 1: SELECT audit_table('company') AS audit_table_1
               ^
HINT:  No function matches the given name and argument types. You might need to add explicit type casts.
 [SQL: 'SELECT audit_table(%(audit_table_2)s) AS audit_table_1'] [parameters: {'audit_table_2': 'company'}] (Background on this error at: http://sqlalche.me/e/f405)

I decided to try something simple to test the functionality, but no activity records are saved (similar to #26)

import sqlalchemy as sa
import sqlalchemy.orm as orm
import sqlalchemy_utils as utils
from sqlalchemy.ext.declarative import declarative_base
from postgresql_audit import VersioningManager


Base = declarative_base()

versioning_manager = VersioningManager()
versioning_manager.init(Base)


class Role(Base):
    name        = sa.Column(sa.String, primary_key=True)
    description = sa.Column(sa.String)

    __tablename__ = 'role'
    __versioned__ = {}


engine_url = 'postgresql+psycopg2://postgres@localhost/pyaudit'

if utils.database_exists(engine_url):
    utils.drop_database(engine_url)

utils.create_database(engine_url)

engine = sa.create_engine(engine_url, echo=True)

Base.metadata.create_all(engine)

session = orm.sessionmaker(bind=engine)()

role = Role(name='test')
session.add(role)
session.commit()

Activity = versioning_manager.activity_cls

activity = session.query(Activity).first()
print(activity)

I’d really like to get this working so I can test the performance against SQLAlchemy-Continuum before putting my project into production. I presume it’ll be difficult to migrate after the fact.

[djlambert]

Did some digging through the tests and added the following code before creating all the tables:

orm.configure_mappers()

versioning_manager.transaction_cls.__table__.create(engine)
versioning_manager.activity_cls.__table__.create(engine)

This seems to have fixed the issue. Is this something missing from the documentation?

[k-dal]

It’s hard to be sure without more context, but I did notice one particularly important omission in the snippets above: versioning_manager.init(Base)

There’s more info on the SQLAlchemy integration here: https://postgresql-audit.readthedocs.io/en/stable/sqlalchemy.html - I found it pretty useful as a basic reference.