pshell raises NoTransaction exception in a project that has no database files (yet)

[pylons]

pshell raises NoTransaction exception in a project that has no database files (yet)

[WuShell]

As suggested in Pylons/pyramid#3137 removing this line:

settings['tm.manager_hook'] = 'pyramid_tm.explicit_manager'
from the main function in init.py in the root of the app makes pshell to work as expected before the database files are created.

Another workaround, change the root_factory method in init.py to be something like this:

def root_factory(request):
    conn = get_connection(request)
    return appmaker(conn.root(), request.tm)

and appmaker:

def appmaker(zodb_root, tm):
    if 'app_root' not in zodb_root:
        app_root = MyModel()
        zodb_root['app_root'] = app_root
        tm.commit()
    return zodb_root['app_root']

So the transaction is commited propertly

[mmerickel]

If you're still suggesting to use the pyramid_tm.explicit_manager then this fix will not work adequately because a commit in the middle of a request will not open a new transaction for later work. Performing a commit in the middle will break things that would have worked or sort-of-worked previously across implicitly-created transactions. At the very least a tm.begin() is required after the commit, but that is not really a good fix either.

[WuShell]

Not really suggesting a fix (yet), it was more like trying to find out what is causing this and what a proper fix could be.

This code is run once, the first time you start the app, as the database has to be created... so I was wondering how much breakage adding a transaction commit there could cause (even if, after the commit, you have to explicitly start a new transaction as you mentioned in your comment)

In previous versions of pyramid, the zodb was created after pshell/pserve/etc finished starting the app, not after the first request finished (which is what is happening now)

Maybe the fix should be made somewhere else, outside appmaker(), ensuring a transaction commit is done once the app has been fully initialized?

[stevepiercy]

The alchemy cookiecutter has a manual step to create the database that uses a script initialize.db. Can that pattern be repeated with ZODB in this cookiecutter?

[mmerickel]

fixed by #35