Mike:
Thanks for your reply.
This is a stock pyramid app built with their SQLA "scaffold." As expected,
any attempt to directly use commit on the session results in:
File
"/home/richard/vp36/lib/python3.6/site-packages/zope.sqlalchemy-0.7.7-py3.6.egg/zope/sqlalchemy/datamanager.py",
line 254, in before_commit
"Transaction must be committed using the transaction manager"
AssertionError: Transaction must be committed using the transaction manager
The SQLA piece seems to be working great, as in the generated SQL is
exactly what I expect. It's a bit frustrating that SQLA is telling me that
everything is cool with the generated SQL, but then ROLLBACK sort of
whimsically appears in the log output.
I'm sure it is not arbitrary, it just looks that way.
I'll give a nested transaction a try, and then see about getting rid of the
zope stuff, so back to "pure" SQLA if I can manage it.
The dbsession is created in the following:
in models.__init__
from sqlalchemy import engine_from_config
from sqlalchemy.orm import sessionmaker
from sqlalchemy.orm import configure_mappers
import zope.sqlalchemy
# import or define all models here to ensure they are attached to the
# Base.metadata prior to any initialization routines
from .stemqmodel import (EdgeNode, Tile, TileStat, TileSub, TileUpd) #
flake8: noqa
# run configure_mappers after defining all of the models to ensure
# all relationships can be setup
configure_mappers()
def get_engine(settings, prefix='sqlalchemy.'):
return engine_from_config(settings, prefix)
def get_session_factory(engine):
factory = sessionmaker()
factory.configure(bind=engine)
return factory
def get_tm_session(session_factory, transaction_manager):
"""
Get a ``sqlalchemy.orm.Session`` instance backed by a transaction.
This function will hook the session to the transaction manager which
will take care of committing any changes.
- When using pyramid_tm it will automatically be committed or aborted
depending on whether an exception is raised.
- When using scripts you should wrap the session in a manager yourself.
For example::
import transaction
engine = get_engine(settings)
session_factory = get_session_factory(engine)
with transaction.manager:
dbsession = get_tm_session(session_factory,
transaction.manager)
"""
dbsession = session_factory()
zope.sqlalchemy.register(
dbsession, transaction_manager=transaction_manager)
return dbsession
def includeme(config):
"""
Initialize the model for a Pyramid app.
Activate this setup using ``config.include('testsqla.models')``.
"""
settings = config.get_settings()
# use pyramid_tm to hook the transaction lifecycle to the request
config.include('pyramid_tm')
session_factory = get_session_factory(get_engine(settings))
config.registry['dbsession_factory'] = session_factory
# make request.dbsession available for use in Pyramid
config.add_request_method(
# r.tm is the transaction manager used by pyramid_tm
lambda r: get_tm_session(session_factory, r.tm),
'dbsession',
reify=True
)
And in the pyramid app __init__ like so:
from pyramid.config import Configurator
from sqlalchemy import engine_from_config
import logging
import time
import socket
#
log = logging.getLogger(__name__)
def main(global_config, **settings):
""" This function returns a Pyramid WSGI application.
"""
### This hack must come before the call to Configurator
config = Configurator(settings=settings)
config.include('pyramid_mako')
config.include('.models')
config.add_static_view('static', 'static', cache_max_age=3600)
config.add_route('home', '/')
config.add_route('register', '/register')
config.add_route('loader', '/loader')
config.add_route('register_edgenode_view', '/registeredgeview')
config.add_route('register_edgenode_action', '/registeredge')
config.add_route('view_edgenode_status', '/viewedgestatus')
config.add_route('test_lineup', '/testlineup')
config.scan()
config.registry['last_request'] = time.time()
return config.make_wsgi_app()
Mostly just generated code, via cookiecutter. The relevant line is:
config.include(.models)
At this point, I miss the old "stock" SQLA integration that made me manage
my own transactions. Ahhhh. . .The good old days.
On Wednesday, June 28, 2017 at 2:28:32 PM UTC-6, Mike Bayer wrote:
>
> I'm not 100% sure that zope.sqlalchemy unconditionally emits COMMIT
> for the session that's associated. Though overall would need to see
> where you're getting request.session from and all that; if it's not
> associated with zope.sqlalchemy then you'd need to call
> session.commit() explicitly.
>
> On Wed, Jun 28, 2017 at 3:43 PM, Jonathan Vanasco <[email protected]
> <javascript:>> wrote:
> >
> >>
> >> On Wednesday, June 28, 2017 at 3:16:52 PM UTC-4, Richard Rosenberg
> wrote:
> >
> >
> > On Wednesday, June 28, 2017 at 3:16:52 PM UTC-4, Richard Rosenberg
> wrote:
> >>
> >>
> >> I am absolutely puzzled, but it seems likely that pyramid_tm is in the
> way
> >> somehow. It always wants to do its own thing, and calling commit
> explicitly
> >> is something it seems to abhor. My next step is to wrap this in:
> >>
> >> with transaction.manager as tx:
> >>
> >> But this is really not what I want. I'm tempted to rip out all of the
> >> zopish stuff and go with SQLA's session, but before I try that, I
> thought it
> >> might be worthwhile to get some further information.
> >>
> >
> > For a quick-fix, i'd try to run this bit within a nested
> > transaction/savepoint:
> >
> > http://docs.sqlalchemy.org/en/latest/orm/session_transaction.html
> >
> >
> > I doubt the problem is in `pyramid_tm`. that package just wraps the
> request
> > in some logic to hook into the transaction package; all the real work is
> > done by `zope.sqlalchemy`. The issue is possibly linked to your version
> of
> > `zope.sqlalchemy` or `pyscopg2` (or other driver). I'd try to update
> > those... but from what I see here, you could probably just dump this
> into a
> > nested transaction, which will limit the scope of the rollback.
> >
> >
> > --
> > SQLAlchemy -
> > The Python SQL Toolkit and Object Relational Mapper
> >
> > http://www.sqlalchemy.org/
> >
> > To post example code, please provide an MCVE: Minimal, Complete, and
> > Verifiable Example. See http://stackoverflow.com/help/mcve for a full
> > description.
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--
SQLAlchemy -
The Python SQL Toolkit and Object Relational Mapper
http://www.sqlalchemy.org/
To post example code, please provide an MCVE: Minimal, Complete, and Verifiable
Example. See http://stackoverflow.com/help/mcve for a full description.
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