Develop Reference

Heroku 409 error when Python Dash app calls API

starting process with command from procfile works.
then as soon as it starts reading the python file, and pulling data from an API, we get
[2020-03-23 17:48:55 +0000] [10] [ERROR] Exception in worker process
Which traces down to
raise HTTPError(req.full_url, code, msg, hdrs, fp)
urllib.error.HTTPError: HTTP Error 409: Conflict
And then
[2020-03-23 17:48:55 +0000] [10] [INFO] Worker exiting (pid: 10)
Before it looks like its successfully calling the API on a second attempt and then ultimately
[2020-03-23 17:49:03 +0000] [11] [INFO] Worker exiting (pid: 11)
[2020-03-23 17:49:04 +0000] [4] [INFO] Shutting down: Master
[2020-03-23 17:49:04 +0000] [4] [INFO] Reason: Worker failed to boot.
And it crashes, exiting with status 3.
How do I solve this 409 error? Is there some environment variable or something that has to be set in the python app before deploying to Heroku? The app works locally (i.e. API calls work), just when trying to put on a server do I encounter this.

Start Django config app only once when using multiple Gunicorn workers

I'm using :
python 3.6
django==2.1.1
gunicorn==19.9.0
i have done the following:
created a django project called api
created an apiapp (an app in my project)
and i have this code in api_app's apps.py :
from django.apps import AppConfig
from api import settings
class ApiappConfig(AppConfig):
name = 'apiapp'
verbose_name = "random_name"
def ready(self):
self.job()
#classmethod
def job(cls):
### doing whatever here for example :
print(settings.SHARED_VARIABLE)
and the following in api_app's __init__.py:
import os
default_app_config = 'apiapp.apps.ApiappConfig'
i'm creating an API so i am required to use multiple workers when deploying:
gunicorn api.wsgi -w 10
now, my issue is that the function job which is called when the server is started, is getting called 10 times because i'm using 10 gunicorn workers, i would like to call it only once
another thing that i would like to do is to have the
settings.SHARED_VARIABLE variable, shared between the different workers. this variable will be updated only by the worker that will launch the app.py on server start.
Thank you !

gunicorn has a setting to do this: --preload
So, after I add this in settings.py: SHARED_VARIABLE = 'content of SHARED_VARIABLE' (and fixed apiapp/__init__.py to use the real app name), I can run gunicorn with the application loaded only once:
$ gunicorn api.wsgi -w 10 --preload
content of SHARED_VARIABLE
[2018-12-31 10:12:15 +0000] [394] [INFO] Starting gunicorn 19.6.0
[2018-12-31 10:12:15 +0000] [394] [INFO] Listening at: http://127.0.0.1:8000 (394)
[2018-12-31 10:12:15 +0000] [394] [INFO] Using worker: sync
[2018-12-31 10:12:15 +0000] [399] [INFO] Booting worker with pid: 399
[2018-12-31 10:12:15 +0000] [400] [INFO] Booting worker with pid: 400
[2018-12-31 10:12:15 +0000] [401] [INFO] Booting worker with pid: 401
[2018-12-31 10:12:15 +0000] [403] [INFO] Booting worker with pid: 403
[2018-12-31 10:12:15 +0000] [404] [INFO] Booting worker with pid: 404
[2018-12-31 10:12:15 +0000] [405] [INFO] Booting worker with pid: 405
[2018-12-31 10:12:15 +0000] [406] [INFO] Booting worker with pid: 406
[2018-12-31 10:12:15 +0000] [408] [INFO] Booting worker with pid: 408
[2018-12-31 10:12:15 +0000] [410] [INFO] Booting worker with pid: 410
[2018-12-31 10:12:15 +0000] [411] [INFO] Booting worker with pid: 411

Which logger is outputting this in gunicorn?

When I start gunicorn it prints this:
[2018-11-09 16:30:20 +0000] [16] [INFO] Starting gunicorn 19.9.0
[2018-11-09 16:30:20 +0000] [16] [INFO] Listening at: http://0.0.0.0:8000 (16)
[2018-11-09 16:30:20 +0000] [16] [INFO] Using worker: sync
[2018-11-09 16:30:20 +0000] [19] [INFO] Booting worker with pid: 19
Setting up a logger for the gunicorn package (propagating) doesn't seem to affect it. What module is the one I should configure to modify these messages?

Those messages are output by the Arbiter class in gunicorn/arbiter.py, but it may be that any configuring you try and do is overridden by gunicorn's machinery, or not applicable - for example, trying to set up logging in a worker won't affect what the arbiter does, as they are separate processes. So you may need to invoke the arbiter in a special way (i.e. not just through running a canned gunicorn script) if you want to affect its logging, or amend the gunicorn configuration used for the arbiter.

Google App Engine deployment issue- main app not found

I am trying to deploy my app using Google App Engine. I have edited app.yaml to reflect the flexible environment and also gave all the app information. Below is the app.yaml file.
runtime: python
env: flex
entrypoint: gunicorn -b :$PORT main:app
runtime_config:
python_version: 3
Once the deployment is in progress, I am getting the following error
[2018-08-24 06:57:14 +0000] [1] [INFO] Starting gunicorn 19.7.1
[2018-08-24 06:57:14 +0000] [1] [INFO] Listening at: http://0.0.0.0:8080 (1)
[2018-08-24 06:57:14 +0000] [1] [INFO] Using worker: sync
[2018-08-24 06:57:14 +0000] [7] [INFO] Booting worker with pid: 7
App Deployed
Failed to find application: 'main'
[2018-08-24 06:57:14 +0000] [7] [INFO] Worker exiting (pid: 7)
[2018-08-24 06:57:14 +0000] [1] [INFO] Shutting down: Master
[2018-08-24 06:57:14 +0000] [1] [INFO] Reason: App failed to load.
Please note that App Deployed is the line in my print statement. It is getting executed. But the deployment is getting failed
Thank you in advance

In your app.yaml, you're starting gunicorn with gunicorn -b :$PORT main:app. This tells it to look for the object app in the file main.py
The error you're getting comes from gunicorn and occurs when you have a main.py file, but it does not have an app object in it.
You probably want to set up a Flask app as follows:
from flask import Flask
app = Flask(__name__)
See a full example app here: https://cloud.google.com/appengine/docs/flexible/python/quickstart#hello_world_code_review

I have had the same issue.
Failed to find application: 'main'
The reason in my case was that I had a directory called also main in the root project directory.
drwxr-xr-x 2 user staff 64 Nov 30 10:12 main
-rw-r--r-- 1 user staff 1178 Nov 29 20:58 main.py
I guess gunicorn got confused.
The solution (worked for me): to rename main directory.
P.S. Just don't rename it to code directory. It will cause another issue with debugging in PyCharm. :)

My folder structure is looks llike this the main.py is not in the root directory how I can specify this in app.yaml file.
/app
|__main.py
app.yaml

No such file or directory New Relic

I'm trying to setup new relic, I have followed the instructions they give however the last command give me this error.
newrelic-admin run-program gunicorn wsgi:application
why?
2013-04-16 10:39:30 [4175] [INFO] Starting gunicorn 0.14.5
2013-04-16 10:39:30 [4175] [INFO] Listening at: http://127.0.0.1:8000 (4175)
2013-04-16 10:39:30 [4175] [INFO] Using worker: sync
2013-04-16 10:39:30 [4178] [INFO] Booting worker with pid: 4178
2013-04-16 10:39:30 [4178] [INFO] Worker exiting (pid: 4178)
2013-04-16 10:39:31 [4175] [INFO] Shutting down: Master
2013-04-16 10:39:31 [4175] [INFO] Reason: Worker failed to boot.

Follow the instructions found here:
https://newrelic.com/docs/python/python-agent-integration
I'm assuming as this i posted in Django that its a Django app.
add
import newrelic.agent
newrelic.agent.initialize('/some/path/newrelic.ini')