ImportError: No module named config on Travis-CI build

import_string only takes absolute module imports. Since config is not a top-level module, but part of webapp, you need to specify webapp.config. See http://flask.pocoo.org/docs/0.10/config/#configuring-from-files:

app = Flask(__name__)app.config.from_object('yourapplication.default_settings')app.config.from_envvar('YOURAPPLICATION_SETTINGS')

I came across this issue recently and could not figure it out until I had an epiphany after 2nd days by reading Markus's answer.

Just in-case someone out there is looking for a solution to load the configuration from config.py and the flask app is using a package structure then ensure to provide the full classpath to the config class file in app.config.from_object().

For e.g., I had a configuration myproj/app/config.py in my flask project myproj and the class file with the configuration was DevelopmentConfig. You need to provide it as follows:

app.config.from_object('app.config.DevelopmentConfig')

Another example would be if you put the same file under myproj/instance/config.py then, you call it as:

app.config.from_object('instance.config.DevelopmentConfig')

During the development of your app, the easiest way to change your settings would be to put an environment variable in myapp/.env file like so:

FLASK_APP=appAPP_SETTINGS="app.config.DevelopmentConfig"

and use the variable in your app.config.from_object() call:

app.config.from_object(os.environ['APP_SETTINGS'])

But do remember that for the .env to take effect, you need to start your app with flask run instead of running the app directly.