The dreaded 502 error

Question

I use Pycharm while creating a website using Django/python. The website works as expected on localhost through Pycharm, so I decided to try and move it to a webserver. I followed this tutorial multiple times but still get the 502 error. https://www.youtube.com/watch?v=Y-CT_l1dnVU&t=609s

Ngnix error reads:

2017/03/01 04:53:33 [error] 2232#2232: *48 connect() to unix:/home/django/gunicorn.socket failed (111: Connection refused) while connecting to upstream, client: *client IP*, server: _, request: "GET / HTTP/1.1", upstream: "http://unix:/home/django/gunicorn.socket:/", host: "*host IP*"

and Gunicorn error reads:

root@ueba:/home/django/django_project# service gunicorn status
● gunicorn.service - Gunicorn daemon for Django Project
   Loaded: loaded (/etc/systemd/system/gunicorn.service; enabled; vendor preset:
   Active: inactive (dead) (Result: exit-code) since Wed 2017-03-01 04:42:29 UTC
  Process: 23288 ExecStart=/usr/bin/gunicorn --name=django_project --pythonpath=
 Main PID: 23288 (code=exited, status=1/FAILURE)

Mar 01 04:42:29 ueba systemd[1]: gunicorn.service: Unit entered failed state.
Mar 01 04:42:29 ueba systemd[1]: gunicorn.service: Failed with result 'exit-code
Mar 01 04:42:29 ueba systemd[1]: gunicorn.service: Service hold-off time over, s
Mar 01 04:42:29 ueba systemd[1]: Stopped Gunicorn daemon for Django Project.
Mar 01 04:42:29 ueba systemd[1]: gunicorn.service: Start request repeated too qu
Mar 01 04:42:29 ueba systemd[1]: Failed to start Gunicorn daemon for Django Proj
lines 1-12/12 (END)

if it matters, the file system is:

*home
   *Django
      *Django_project
          *Django_project
             *wsgi.py
             *init.py
             *settings.py
             *urls.py
          *ueba
             *migrations (folder)
             *static (folder)
             *templates (folder)
             *init.py
             *admin.py
             *apps.py
             *tests.py
             *views.py
             *models.py

I feel like I’ve tried multiple suggestions and variations of configs for both the ngnix and gunicorn through docs on OD but still haven’t nailed it out.

Let me know if I need to provide more docs, thanks!

Answer 1

hansen March 1, 2017

You only have to look at your Django project (or Gunicorn more specifically). This has nothing to do with Nginx, right now at least, since you can’t even run Gunicorn.
Try starting it with debug level, in hope to get a better error message than “exit-code”:
gunicorn_django -b 127.0.0.1:8000 --settings=myapp.settings.dev --debug --log-level debug
Modify the command, so it fits your project, just leave the –debug –log-level debug

Reply Report

bdave March 1, 2017

I’m assuming that the only thing I change is ‘myapp’ to fit my project, but then get an error:

usage: gunicorndjango [OPTIONS] [SETTINGS_PATH]
gunicorndjango: error: unrecognized arguments: –debug
Reply Report
- hansen March 1, 2017
  
  Sorry, don’t work with Gunicorn, just remove the –debug but leave the –log-level debug
  If that doesn’t work, then you need to go “nuclear” with –spew
  http://docs.gunicorn.org/en/stable/settings.html#spew
  
  Reply Report
  
  bdave March 1, 2017
  
  Okay, I got quit the long response. Is there something I should look for, or do you want me to post it?
  
  I should also mention that, while following the YouTube tutorial, when I change everything it says to change other then the database stuff (keeping it sqlite) I can get regular Django errors when loading the webpage (Like “no such table: team_history”). When I change it to MySQL, that’s when I get the 502. I’m not sure what error is closer to getting the webpage to work.
  
  Reply Report
  
  hansen March 1, 2017
  
  Great, then it’s probably something to do with the configuration of MySQL or how it’s loaded (used, code-wise) in the project.
  Can you post the database configuration (EDIT: the config in your project) - both the SQLite and MySQL?
  If we still can’t figure it out, then it’s probably easier to post to pastebin.com and then we write the solution here - in the hope, we find it :-)
  
  Reply Report
  
  bdave March 2, 2017
  
  I just want to use MySQL, the database config I use, that works, to connect to MySQL Workbench on my local machine is:
  
  ‘default’: {
  'ENGINE’: 'django.db.backends.mysql’,
  'NAME’: 'ueba’,
  'USER’: 'root’,
  'PASSWORD’: ’password’,
  'HOST’: 'localhost’,
  'PORT’: '3306’,
  }
  
  I installed MySQL on DO, and set that database config to:
  
  'default’: {
  'ENGINE’: 'django.db.backends.mysql’,
  'NAME’: 'ueba’,
  'USER’: 'root’, (user used to login to MySQL on DO)
  'PASSWORD’: ’password’, (used to login to MySQL on DO)
  'HOST’: '174.138.77.90’,
  'PORT’: '3306’,
  }
  
  My guess is that I want my website to connect to the MySQL on DO, but then populate the DO database from MySQL Workbench?
  
  Reply Report
  
  hansen March 2, 2017
  
  @bdave
  But do you have your MySQL on a different server than Gunicorn?
  If yes, then you should use “private” network on DO, since it’s faster.
  If no, then you should still use 'HOST': 'localhost',
  
  Reply Report
  
  hansen March 2, 2017
  
  @bdave
  And since your project was working fine with SQLite, then please post that configuration, since there must be a difference.
  From what I remember of Django, the configuration is in JSON format, which is very strict, so the comma at the end is not allowed for the final child.
  'PORT': '3306', should be 'PORT': '3306'
  
  Reply Report
  
  bdave March 2, 2017
  
  SQLite settings are the default ones:
  
  ‘default’: {
  'ENGINE’: 'django.db.backends.sqlite3’,
  'NAME’: os.path.join(BASE_DIR, 'db.sqlite3’),
  }
  
  With further messing around, I noticed I can make migrations by using 'python manage.py migrate’ while using SQLite, but get “ImportError: No module named pymysql” when trying with MySQL.
  
  Reply Report
  
  hansen March 2, 2017
  
  @bdave
  You might be able to get better help by going to a Django-only based forum, since this is getting into something, which I haven’t played with.
  I would recommend this: http://stackoverflow.com/tags/django/
  
  Reply Report
bdave March 2, 2017

@hansen
Thanks for sticking with me thus far and sorry for the long posts, but following the tutorial for ngnix/gunicorn/Django. I managed to get all the way up to running with Gunicorn on my local machine but haven’t gotten past that point. So I do think it’s a gunicorn issue. Running the debug command you provided earlier, it gives me:

ImportError: No module named validation

And for good measure, here is my gunicorn config file:

[Unit]
Description=Gunicorn daemon
After=network.target

[Service]
User=django
Group=www-data
WorkingDirectory=/home/django/djangoproject
ExecStart=/home/django/djanoproject/uebaenv/bin/gunicorn –workers 3 –bind unix:/home/django/djangoproject/djangoproject.sock django_project.wsgi:application

[Install]
WantedBy=multi-user.target
Reply Report
- hansen March 2, 2017
  
  Are you executing with gunicorn or gunicorn_django ? Seems like I might have supplied old information, since gunicorn_django is no longer recommended.
  https://www.digitalocean.com/community/tutorials/how-to-deploy-a-local-django-app-to-a-vps?comment=12057
  
  And you’re not allow running gunicorn as root either, so prefix the command with sudo -E should fix that:
  http://stackoverflow.com/questions/28664535/deploying-django-with-gunicorn-no-module-named-importerror-no-module-named-vali#comment45637105_28670151
  
  And you had an error in one of the previous comments, which looked like the MySQL module wasn’t installed in python. Have a look at this comment to ensure you have that installed:
  https://www.digitalocean.com/community/tutorials/how-to-deploy-a-local-django-app-to-a-vps?comment=12075
  
  How To Deploy a Local Django App to a VPS
  by Stephen Tippets
  Here you'll learn how to deploy a local Django app to a VPS.
  
  Reply Report

Answer 2

bdave March 1, 2017

I’m assuming that the only thing I change is ‘myapp’ to fit my project, but then get an error:

usage: gunicorndjango [OPTIONS] [SETTINGS_PATH]
gunicorndjango: error: unrecognized arguments: –debug
Reply Report
- hansen March 1, 2017
  
  Sorry, don’t work with Gunicorn, just remove the –debug but leave the –log-level debug
  If that doesn’t work, then you need to go “nuclear” with –spew
  http://docs.gunicorn.org/en/stable/settings.html#spew
  
  Reply Report
  
  bdave March 1, 2017
  
  Okay, I got quit the long response. Is there something I should look for, or do you want me to post it?
  
  I should also mention that, while following the YouTube tutorial, when I change everything it says to change other then the database stuff (keeping it sqlite) I can get regular Django errors when loading the webpage (Like “no such table: team_history”). When I change it to MySQL, that’s when I get the 502. I’m not sure what error is closer to getting the webpage to work.
  
  Reply Report
  
  hansen March 1, 2017
  
  Great, then it’s probably something to do with the configuration of MySQL or how it’s loaded (used, code-wise) in the project.
  Can you post the database configuration (EDIT: the config in your project) - both the SQLite and MySQL?
  If we still can’t figure it out, then it’s probably easier to post to pastebin.com and then we write the solution here - in the hope, we find it :-)
  
  Reply Report
  
  bdave March 2, 2017
  
  I just want to use MySQL, the database config I use, that works, to connect to MySQL Workbench on my local machine is:
  
  ‘default’: {
  'ENGINE’: 'django.db.backends.mysql’,
  'NAME’: 'ueba’,
  'USER’: 'root’,
  'PASSWORD’: ’password’,
  'HOST’: 'localhost’,
  'PORT’: '3306’,
  }
  
  I installed MySQL on DO, and set that database config to:
  
  'default’: {
  'ENGINE’: 'django.db.backends.mysql’,
  'NAME’: 'ueba’,
  'USER’: 'root’, (user used to login to MySQL on DO)
  'PASSWORD’: ’password’, (used to login to MySQL on DO)
  'HOST’: '174.138.77.90’,
  'PORT’: '3306’,
  }
  
  My guess is that I want my website to connect to the MySQL on DO, but then populate the DO database from MySQL Workbench?
  
  Reply Report
  
  hansen March 2, 2017
  
  @bdave
  But do you have your MySQL on a different server than Gunicorn?
  If yes, then you should use “private” network on DO, since it’s faster.
  If no, then you should still use 'HOST': 'localhost',
  
  Reply Report
  
  hansen March 2, 2017
  
  @bdave
  And since your project was working fine with SQLite, then please post that configuration, since there must be a difference.
  From what I remember of Django, the configuration is in JSON format, which is very strict, so the comma at the end is not allowed for the final child.
  'PORT': '3306', should be 'PORT': '3306'
  
  Reply Report
  
  bdave March 2, 2017
  
  SQLite settings are the default ones:
  
  ‘default’: {
  'ENGINE’: 'django.db.backends.sqlite3’,
  'NAME’: os.path.join(BASE_DIR, 'db.sqlite3’),
  }
  
  With further messing around, I noticed I can make migrations by using 'python manage.py migrate’ while using SQLite, but get “ImportError: No module named pymysql” when trying with MySQL.
  
  Reply Report
  
  hansen March 2, 2017
  
  @bdave
  You might be able to get better help by going to a Django-only based forum, since this is getting into something, which I haven’t played with.
  I would recommend this: http://stackoverflow.com/tags/django/
  
  Reply Report
bdave March 2, 2017

@hansen
Thanks for sticking with me thus far and sorry for the long posts, but following the tutorial for ngnix/gunicorn/Django. I managed to get all the way up to running with Gunicorn on my local machine but haven’t gotten past that point. So I do think it’s a gunicorn issue. Running the debug command you provided earlier, it gives me:

ImportError: No module named validation

And for good measure, here is my gunicorn config file:

[Unit]
Description=Gunicorn daemon
After=network.target

[Service]
User=django
Group=www-data
WorkingDirectory=/home/django/djangoproject
ExecStart=/home/django/djanoproject/uebaenv/bin/gunicorn –workers 3 –bind unix:/home/django/djangoproject/djangoproject.sock django_project.wsgi:application

[Install]
WantedBy=multi-user.target
Reply Report
- hansen March 2, 2017
  
  Are you executing with gunicorn or gunicorn_django ? Seems like I might have supplied old information, since gunicorn_django is no longer recommended.
  https://www.digitalocean.com/community/tutorials/how-to-deploy-a-local-django-app-to-a-vps?comment=12057
  
  And you’re not allow running gunicorn as root either, so prefix the command with sudo -E should fix that:
  http://stackoverflow.com/questions/28664535/deploying-django-with-gunicorn-no-module-named-importerror-no-module-named-vali#comment45637105_28670151
  
  And you had an error in one of the previous comments, which looked like the MySQL module wasn’t installed in python. Have a look at this comment to ensure you have that installed:
  https://www.digitalocean.com/community/tutorials/how-to-deploy-a-local-django-app-to-a-vps?comment=12075
  
  How To Deploy a Local Django App to a VPS
  by Stephen Tippets
  Here you'll learn how to deploy a local Django app to a VPS.
  
  Reply Report

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