I am trying to run alembic migration and when I run
alembic revision --autogenerate -m "Added initial tables"
It fails saying
sqlalchemy.exc.ArgumentError: Can't load plugin: sqlalchemy.dialects:driver
the database url is
postgresql+psycopg2://dev:passwd@localhost/db
and I even have psycopg2 installed in my virtualenv
$yolk -l
Flask-Login - 0.1.3 - active
Flask-SQLAlchemy - 0.16 - active
Flask - 0.9 - active
Jinja2 - 2.6 - active
Mako - 0.7.3 - active
MarkupSafe - 0.15 - active
Python - 2.7.2 - active development (/System/Library/Frameworks/Python.framework/Versions/2.7/lib/python2.7/lib-dynload)
SQLAlchemy - 0.8.0 - active
Werkzeug - 0.8.3 - active
alembic - 0.4.2 - active
antiorm - 1.1.1 - active
appscript - 1.0.1 - active
distribute - 0.6.27 - active
envoy - 0.0.2 - active
osascript - 0.0.4 - active
pep8 - 1.4.5 - active
pip - 1.1 - active
psycopg2 - 2.4.6 - active
wsgiref - 0.1.2 - active development (/System/Library/Frameworks/Python.framework/Versions/2.7/lib/python2.7)
yolk - 0.4.3 - active
Whay could be causing this issue?
Here's how to produce an error like that:
>>> from sqlalchemy import *
>>> create_engine("driver://")
Traceback (most recent call last):
... etc
sqlalchemy.exc.ArgumentError: Can't load plugin: sqlalchemy.dialects:driver
so I'd say you aren't actually using the postgresql URL you think you are - you probably are calling upon a default-generated alembic.ini somewhere.