Looks like your callback function has a wrong signature. Try the following.
from eve import Eve
def before_insert(resource_name, items):
print 'About to return artists'
app = Eve(settings='settings.py')
app.on_insert += before_insert
if __name__ == '__main__':
app.run(debug=True)
In any case, try running the app with DEBUG = True
in your settings file, or run it with app.run(debug=True)
, so you can get a hint on what the actual problem is.