Python Flask application not deployable on AWS Elastic Beanstalk | No module named 'application'

Question

Error message in web.stdout.log:

Oct 15 13:03:29 ip-172-31-18-218 web: ModuleNotFoundError: No module named 'application'
Oct 15 13:03:29 ip-172-31-18-218 web: [2020-10-15 13:03:29 +0000] [4633] [INFO] Worker exiting (pid: 4633)
Oct 15 13:03:29 ip-172-31-18-218 web: [2020-10-15 13:03:29 +0000] [4626] [INFO] Shutting down: Master
Oct 15 13:03:29 ip-172-31-18-218 web: [2020-10-15 13:03:29 +0000] [4626] [INFO] Reason: Worker failed to boot.

Error message in nginx/error.log

2020/10/15 13:04:21 [error] 4559#0: *19 connect() failed (111: Connection refused) while connecting to upstream, client: 172.31.42.151, server: , request: "GET / HTTP/1.1", upstream: "http://127.0.0.1:8000/", host: "172.31.18.218"

Flask app:

# EB looks for an 'application' callable by default.
application = Flask(__name__)

@application.route('/')
def home(): 
    return "Hello World"

@application.route('/processImage')
def index():
    [Some Code...]

if __name__ == '__main__':
    # Setting debug to True enables debug output. This line should be
    # removed before deploying a production app.
    application.run('localhost',8000,debug=True)

requirements.txt

certifi==2020.6.20
chardet==3.0.4
click==7.1.2
Flask==1.1.2
idna==2.10
itsdangerous==1.1.0
Jinja2==2.11.2
MarkupSafe==1.1.1
numpy==1.19.2
opencv-python==4.4.0.44
requests==2.24.0
urllib3==1.25.10
Werkzeug==1.0.1
    

My folder structure:

eb-flask
  |- .vscode (folder)
  |- images (folder)
  |- application.py
  |- requirements.txt

Way of deployment:

Deployment via the Elastic Beanstalk Web UI by uploading a .zip archive of the above described folder. 

Any ideas on how to further debug or solve this would be highly appreciated. Thanks a lot in advance.

Answer 1

You might need to add the modules to the environments path variable so that the module lookup is sucessful. Run the following from a file/ command line-

import sys
import os
sys.path.append("/path_to_your_app/eb-flask")

Answer 2

您正在端口 8000 上运行您的应用程序。但是，EB 会期望它在端口 5000 上运行。因此，您要么更改 EB 上的默认端口，要么修改您的应用程序以在端口 5000 上运行：

application.run('localhost', 5000,debug=True)

Answer 3

I was getting the same error.

Few things I did was:

1. Made a change: application = app = Flask(__name__) .
2. Renamed the python file to application.py .

Also very important: whatever files are required select those and zip them (right-click "send to" -> "compressed" in windows) and upload to the beanstalk.

DO NOT put all the required files in a folder and zip. This was the reason behind ModuleNotFound: No Module name 'application' .