Warning message while running Flask

Question

While I am running Flask code from my command line, a warning is appearing:

Serving Flask app \"hello_flask\" (lazy loading)
* Environment: production
  WARN         


        

Answer 1

in configurations or config you can add this code : ENV = ""

same as if you try to add debug set to true like this DEBUG = True

for more detail you can check this http://flask.pocoo.org/docs/1.0/config/#ENV

Answer 2

If you encounter NoAppException and you see lazy loading the following seemed to fix the issue:

cd <project directory>
export FLASK_APP=.
export FLASK_ENV=development
export FLASK_DEBUG=1

Answer 3

To remove the "Do not use the development server in a production environment." warning, run:

export FLASK_ENV=development

before flask run.

Answer 4

I have been using flask for quite some time now, and today, suddenly this warning turned up. I found this.

As mentioned here, as of flask version 1.0 the environment in which a flask app runs is by default set to production. If you run your app in an older flask version, you won't be seeing this warning.

New in version 1.0.

Changelog

The environment in which the Flask app runs is set by the FLASK_ENV environment variable. If not set it defaults to production. The other recognized environment is development. Flask and extensions may choose to enable behaviors based on the environment.

Answer 5

Try gevent:

from flask import Flask
from gevent.pywsgi import WSGIServer

app = Flask(__name__)

@app.route('/api', methods=['GET'])
def index():
    return "Hello, World!"

if __name__ == '__main__':
    # Debug/Development
    # app.run(debug=True, host="0.0.0.0", port="5000")
    # Production
    http_server = WSGIServer(('', 5000), app)
    http_server.serve_forever()

Note: Install gevent using pip install gevent

Answer 6

First, try to the following :

set FLASK_ENV=development 

then run your app.