Enable debug mode in Flask in production mode

Question

In bottle all i have to do to enable debug mode is:

from bottle import debug

application = Bottle()
app = application
debug(True)

How can i do the same in Flask framework?

Answer 1

To enable the debug mode I would add the following code to the flask app:

app.config['ENV'] = 'development'
app.config['DEBUG'] = True
app.config['TESTING'] = True

I would also sugest setting environment variables for the environment and debug.

$ export FLASK_ENV=development 
$ export FLASK_DEBUG=1

Answer 2

If you're in development environment; you can simply specify it in your Flask.run as specified here .

Example:

app.run(host='0.0.0.0', port='8080', debug=True)

You can also take another approach at modifying the default_config as shown here .

Example:

app.config['DEBUG'] = True
app.run(host='0.0.0.0', port='8080')

or even exporting FLASK_DEBUG=1 - Keep in mind that FLASK_DEBUG overrides FLASK_ENV=development .

As you can see below Flask denotes the following:

Do not enable debug mode when deploying in production.

Although as you stated you'd love to have debugging enabled on production; hence why I wouldn't use the Flask.run since it's meant to be used on a development environment, and I would certainly not set the FLASK_ENV to development .

I would suggest you rethink the concept of debugging on production, since production is not meant for debugging; simply put, I believe your reasoning of wanting to debug on production is wrong.

Another possible solution is to use the following (forked, multi-process):

from werkzeug.debug import DebuggedApplication  
application = DebuggedApplication(app, True)

Answer 3

With version 1.0 of Flask, you can set environment variables to be auto imported when you run the flask command, you need to have installed python-dotenv though.

Then you can just create a new file in your top level directory named .flaskenv and set your environment variables in it:

FLASK_APP=run.py
FLASK_DEBUG=1

Answer 4

Follow up with Gil Sousa'S answer, if anybody is facing the same issue in windows

add these three lines in you code in you file,

app.config['ENV'] = 'development'
app.config['DEBUG'] = True
app.config['TESTING'] = True

And also in the cmd or in your anaconda prompt type these commands to set up the debugging mode,

$ set FLASK_ENV=development 
$ set FLASK_DEBUG=1

and don't forget to pass debug=True inside app.run() as a argument.

PS: if you are following this answer, FYKI, now flask apps are using the command $set FLASK_APP=app.py then $FLASK run to run a flask app. This is only for windows for Linux use export instead of set .

Answer 5

In the flask library, you can enable the built-in debug mode using the following steps.

Step 1: Create a virtual environment (a best practice) in your project file:

python -m venv webserver

Or, using python3

python3 -m venv webserver

where the webserver denotes the location of the virtual environment and the folder will be saved as the "webserver".

A best practice is to use the folder name as "venv".

Step 2: Using Windows Powershell, navigate to your project folder

cd "location of the project folder"

Step 3: Set the flask app variable to specify the python script name:

$env:FLASK_APP="server.py"

Step 4: Set the flask environment variable to specify the environment type as "development" to activate the debugger:

$env:FLASK_ENV="development"

Step 5: Activate the project's virtual environment:

venv\scripts\activate

Step 6: Run the flask application:

flask run