pyramid transaction.manager doesn't update object - python-3.x

Question

How can I update a row in DB using transaction.manager in Pyramid? Here is what I have:
DBSession:
DBSession = scoped_session(sessionmaker(extension=ZopeTransactionExtension()))
View:
def create_update(request, post):
title = request.POST.get('title', None)
content = request.POST.get('content', None)
post.title = title
post.content = content
with transaction.manager:
if post.id is None:
DBSession.add(post)
transaction.commit()
This is how I get an existing post from DB:
def by_slug(slug):
return DBSession.query(BlogPost).filter(BlogPost.slug == slug).first()
where BlogPost is a sqlalchemy model.
When I create a new post, everything is fine, it is added and saved in DB, however, nothing happens when I edit an existing post. I've tried DBSession.flush(), result is the same - I can create a new post, but existing one is not updated. What am I missing?

Answer 1

Why your use transaction here?
The ZopeTransactionExtension on the DBSession in conjunction with the pyramid_tm being active on your project will handle all commits for you.
so just try this:
def create_update(request, post):
title = request.POST.get('title', None)
content = request.POST.get('content', None)
post.title = title
post.content = content
if post.id is None:
DBSession.add(post)

Answer 2

Apparently, the issue was, that I didn't have pyramid_tm under pyramid.includes in ini configuration:
[app:main]
use = egg:myproject
pyramid.includes =
pyramid_jinja2
pyramid_tm #this was missing
Weird, that I was not seeing any errors or anything, and it sort of worked, but was giving a lot of headaches.