Ggtcf

I have a flask app that are running in a local machine when runing flask run but it's not running in an AWS EC2.

• Both environment have Ubuntu 16.04 and Python 2.7.


• Both are running in virtualenvs created in the same way and path (only user's folder is different).


• Both have the same Flask version.


• Both have python-dotenv and .flaskenv file and are set to
  development and debug.


• Both have the same project folder (same git repo) and I flask run
  in the same folder for both.


• I defined the PORT in .flaskenv and I can see that the PORT defined
  in there is where flask is running in both.

When I try to get the same URL, in EC2 I got an error: NoAppException: Could not import "app.initialize"

Running in local machine:

$ flask run
 * Serving Flask app "app.initialize:web_app" (lazy loading)
 * Environment: development
 * Debug mode: on
 * Running on http://0.0.0.0:5324/ (Press CTRL+C to quit)
 * Restarting with stat
 * Debugger is active!
 * Debugger PIN: 179-083-368

Log:

127.0.0.1 - - [07/Mar/2019 09:10:13] "GET /api/directors/me/info HTTP/1.0" 200 -

Running un EC2:

$ flask run
 * Serving Flask app "app.initialize:web_app" (lazy loading)
 * Environment: development
 * Debug mode: on
 * Running on http://0.0.0.0:5324/ (Press CTRL+C to quit)
 * Restarting with stat
 * Debugger is active!
 * Debugger PIN: 104-758-876

Log:

127.0.0.1 - - [07/Mar/2019 12:05:42] "GET /api/directors/me/info HTTP/1.0" 500 -
Traceback (most recent call last):
 File "/home/myuser/.virtualenvs/myvenv/lib/python2.7/site-packages/flask/cli.py", line 325, in __call__
 self._flush_bg_loading_exception()
 File "/home/myuser/.virtualenvs/myvenv/lib/python2.7/site-packages/flask/cli.py", line 313, in _flush_bg_loading_exception
 reraise(*exc_info)
 File "/home/myuser/.virtualenvs/myvenv/lib/python2.7/site-packages/flask/cli.py", line 302, in _load_app
 self._load_unlocked()
 File "/home/myuser/.virtualenvs/myvenv/lib/python2.7/site-packages/flask/cli.py", line 317, in _load_unlocked
 self._app = rv = self.loader()
 File "/home/myuser/.virtualenvs/myvenv/lib/python2.7/site-packages/flask/cli.py", line 371, in load_app
 app = locate_app(self, import_name, name)
 File "/home/myuser/.virtualenvs/myvenv/lib/python2.7/site-packages/flask/cli.py", line 246, in locate_app
 'Could not import "name".'.format(name=module_name)
NoAppException: Could not import "app.initialize".

For this app, I have a custom flask command and when I try to call this command for both environment, on the local machine works fine, but in EC2 I got a No such command error.

I really tried everything I found in SO about checking if things are getting imported right, packages versions and etc. In EC2, when I ipython, I can import app.initialize and I can even import models and use my app code to run things, including the command function.

Finally, if I run this app using Gunicorn in EC2, its works fine, but sometime I need to run with flask for debug (its a sandbox environment) and I need to run custom commands too.

Any idea what may be wrong in EC2?

Ty All

You need to add the path to app to the ec2's python path. If you're in the directory of the project, run export PYTHONPATH="$(pwd):$PYTHONPATH".

Basically if your project looks something like this in the file system:

/home
 /myuser
 /myproject
 /app
 __init__.py
 somemodule.py

Then you want to have /home/myuser/myproject present in the environment variable PYTHONPATH.

You'll want to automate this since that environment variable will only be present in the shell you ran the command in. To do that you these are some potential options:

• There may be a way for you to configure environment variables via the AWS UI (not sure).


• You can create or use an image that already has PYTHONPATH set up and make sure you put your project in the path.


• You can add the export command to ~/.profile if you are running a shell as the same user that will be running the application, or /etc/profile if you just want to add the path to the application for all users. Then reboot the server.

But before worrying about that, to test that the solution is correct follow these steps:

1. SSH into the ec2 instance


2. Start a python shell with python
   


3. Run this statement (it should fail due to an import error): import app.initialize
   


4. Exit the shell with exit() or ctrl-d


5. Export the path to app
   


6. Repeat steps 2-3, except this time they should succeed