Python bcrypt package on Heroku gives AttributeError: 'module' object has no attribute 'ffi'
<p>I'm having a problem using bcrypt with my Flask application on Heroku. When I deploy to Heroku and go to the login route I get 500 Internal server error.  It works correctly locally.  How do I get the bcrypt package working on Heroku?</p>

<pre><code>ERROR in app: Exception on /login [POST]
Traceback (most recent call last):
  File "/app/.heroku/python/lib/python2.7/site-packages/flask/app.py", line 1639, in full_dispatch_request
    rv = self.dispatch_request()
  File "/app/.heroku/python/lib/python2.7/site-packages/flask/app.py", line 1625, in dispatch_request
    return self.view_functions[rule.endpoint](**req.view_args)
  File "/app/.heroku/python/lib/python2.7/site-packages/flask_restful/__init__.py", line 477, in wrapper
    resp = resource(*args, **kwargs)
  File "/app/.heroku/python/lib/python2.7/site-packages/flask/views.py", line 84, in view
    return self.dispatch_request(*args, **kwargs)
  File "/app/.heroku/python/lib/python2.7/site-packages/flask_restful/__init__.py", line 587, in dispatch_request
    resp = meth(*args, **kwargs)
  File "/app/app.py", line 196, in post
    elif bcrypt.check_password_hash(user.password, password):
  File "/app/.heroku/python/lib/python2.7/site-packages/flask_bcrypt.py", line 193, in check_password_hash
    return safe_str_cmp(bcrypt.hashpw(password, pw_hash), pw_hash)
  File "/app/.heroku/python/lib/python2.7/site-packages/bcrypt/__init__.py", line 82, in hashpw
    hashed = _bcrypt.ffi.new("char[]", 128)
AttributeError: 'module' object has no attribute 'ffi'
</code></pre>

<p>I've found the solution, I was using the following packages: bcrypt, flask_bcrypt and py-crypt. So I uninstall the py-bcrypt, probably this package was in conflict with bcrypt package.</p>

<pre><code>pip uninstall py-bcrypt
</code></pre>

python heroku flask bcrypt