Nginx 502 - django - GCP

Question

Hi,I am trying to deploy my Django website on google cloud using tutorial (https://cloud.google.com/python/django/appengine#cloud-console ) My website is working smoothly on local host as well on Heroku (Free). But when i try to deploy my website on GCP, deployment finishes without any error. But access to website using the link provided by GCP gives mei ‘nginx 502 Bad Gateway’ error. I assume, error is because its listening to ‘http://0.0.0.0:8081 ’. Can anyone please help. Below are my logs: Traceback from GCP website: 2020-06-20 12:02:57.759 IST Traceback (most recent call last): File "/env/lib/python3.7/site-packages/gunicorn/arbiter.py", line 583, in spawn_worker worker.init_process() File "/env/lib/python3.7/site-packages/gunicorn/workers/gthread.py", line 92, in init_process super().init_process() File "/env/lib/python3.7/site-packages/gunicorn/workers/base.py", line 119, in init_process self.load_wsgi() File "/env/lib/python3.7/site-packages/gunicorn/workers/base.py", line 144, in load_wsgi self.wsgi = self.app.wsgi() File "/env/lib/python3.7/site-packages/gunicorn/app/base.py", line 67, in wsgi self.callable = self.load() File "/env/lib/python3.7/site-packages/gunicorn/app/wsgiapp.py", line 49, in load return self.load_wsgiapp() File "/env/lib/python3.7/site-packages/gunicorn/app/wsgiapp.py", line 39, in load_wsgiapp return util.import_app(self.app_uri) File "/env/lib/python3.7/site-packages/gunicorn/util.py", line 358, in import_app mod = importlib.import_module(module) File "/opt/python3.7/lib/python3.7/importlib/__init__.py", line 127, in import_module return _bootstrap._gcd_import(name[level:], package, level) File "", line 1006, in _gcd_import File "", line 983, in _find_and_load File "", line 965, in _find_and_load_unlocked ModuleNotFoundError: No module named 'main' Expand all | Collapse all{ insertId: "5eedad99000b96b31054c1f8" labels: { clone_id: "00c61b117ceed98b6a28aa8b70411a0a5acbb82696fd9c6894b1680eeaf75adfbafe66" } logName: "projects/school-website-272007/logs/stderr" receiveTimestamp: "2020-06-20T06:32:57.952414554Z" resource: { labels: { module_id: "default" project_id: "school-website-272007" version_id: "20200620t115649" zone: "asia-south1-2" } type: "gae_app" } textPayload: "Traceback (most recent call last): File "/env/lib/python3.7/site-packages/gunicorn/arbiter.py", line 583, in spawn_worker worker.init_process() File "/env/lib/python3.7/site-packages/gunicorn/workers/gthread.py", line 92, in init_process super().init_process() File "/env/lib/python3.7/site-packages/gunicorn/workers/base.py", line 119, in init_process self.load_wsgi() File "/env/lib/python3.7/site-packages/gunicorn/workers/base.py", line 144, in load_wsgi self.wsgi = self.app.wsgi() File "/env/lib/python3.7/site-packages/gunicorn/app/base.py", line 67, in wsgi self.callable = self.load() File "/env/lib/python3.7/site-packages/gunicorn/app/wsgiapp.py", line 49, in load return self.load_wsgiapp() File "/env/lib/python3.7/site-packages/gunicorn/app/wsgiapp.py", line 39, in load_wsgiapp return util.import_app(self.app_uri) File "/env/lib/python3.7/site-packages/gunicorn/util.py", line 358, in import_app mod = importlib.import_module(module) File "/opt/python3.7/lib/python3.7/importlib/__init__.py", line 127, in import_module return _bootstrap._gcd_import(name[level:], package, level) File "", line 1006, in _gcd_import File "", line 983, in _find_and_load File "", line 965, in _find_and_load_unlocked ModuleNotFoundError: No module named 'main'" timestamp: "2020-06-20T06:32:57.759475Z" } After GCP deploy and ‘gcloud app logs tail -s default’ generates log as below. 2020-06-20 06:51:07 default[20200620t115649] Traceback (most recent call last): File "/env/lib/python3.7/site-packages/gunicorn/arbiter.py", line 583, in spawn_worker worker.init_process() File "/env/lib/python3.7/site-p ackages/gunicorn/workers/gthread.py", line 92, in init_process super().init_process() File "/env/lib/python3.7/site-packages/gunicorn/workers/base.py", line 119, in init_process self.load_wsgi() File "/env/lib/python 3.7/site-packages/gunicorn/workers/base.py", line 144, in load_wsgi self.wsgi = self.app.wsgi() File "/env/lib/python3.7/site-packages/gunicorn/app/base.py", line 67, in wsgi self.callable = self.load() File "/env/li b/python3.7/site-packages/gunicorn/app/wsgiapp.py", line 49, in load return self.load_wsgiapp() File "/env/lib/python3.7/site-packages/gunicorn/app/wsgiapp.py", line 39, in load_wsgiapp return util.import_app(self.app_u ri) File "/env/lib/python3.7/site-packages/gunicorn/util.py", line 358, in import_app mod = importlib.import_module(module) File "/opt/python3.7/lib/python3.7/importlib/__init__.py", line 127, in import_module return _bootstrap._gcd_import(name[level:], package, level) File "", line 1006, in _gcd_import File "", line 983, in _find_and_load File "", l ine 965, in _find_and_load_unlocked ModuleNotFoundError: No module named 'main' 2020-06-20 06:51:07 default[20200620t115649] [2020-06-20 06:51:07 +0000] [21] [INFO] Worker exiting (pid: 21) 2020-06-20 06:51:07 default[20200620t115649] [2020-06-20 06:51:07 +0000] [7] [INFO] Shutting down: Master 2020-06-20 06:51:07 default[20200620t115649] [2020-06-20 06:51:07 +0000] [7] [INFO] Reason: Worker failed to boot. 2020-06-20 06:51:08 default[20200620t115649] "GET /favicon.ico HTTP/1.1" 502 2020-06-20 06:51:09 default[20200620t115649] [2020-06-20 06:51:09 +0000] [7] [INFO] Starting gunicorn 20.0.4 2020-06-20 06:51:09 default[20200620t115649] [2020-06-20 06:51:09 +0000] [7] [INFO] Listening at: http://0.0.0.0:8081 (7) 2020-06-20 06:51:09 default[20200620t115649] [2020-06-20 06:51:09 +0000] [7] [INFO] Using worker: threads 2020-06-20 06:51:09 default[20200620t115649] [2020-06-20 06:51:09 +0000] [18] [INFO] Booting worker with pid: 18 2020-06-20 06:51:09 default[20200620t115649] [2020-06-20 06:51:09 +0000] [18] [ERROR] Exception in worker process 2020-06-20 06:51:09 default[20200620t115649] Traceback (most recent call last): File "/env/lib/python3.7/site-packages/gunicorn/arbiter.py", line 583, in spawn_worker worker.init_process() File "/env/lib/python3.7/site-p ackages/gunicorn/workers/gthread.py", line 92, in init_process super().init_process() File "/env/lib/python3.7/site-packages/gunicorn/workers/base.py", line 119, in init_process self.load_wsgi() File "/env/lib/python 3.7/site-packages/gunicorn/workers/base.py", line 144, in load_wsgi self.wsgi = self.app.wsgi() File "/env/lib/python3.7/site-packages/gunicorn/app/base.py", line 67, in wsgi self.callable = self.load() File "/env/li b/python3.7/site-packages/gunicorn/app/wsgiapp.py", line 49, in load return self.load_wsgiapp() File "/env/lib/python3.7/site-packages/gunicorn/app/wsgiapp.py", line 39, in load_wsgiapp return util.import_app(self.app_u ri) File "/env/lib/python3.7/site-packages/gunicorn/util.py", line 358, in import_app mod = importlib.import_module(module) File "/opt/python3.7/lib/python3.7/importlib/__init__.py", line 127, in import_module return _bootstrap._gcd_import(name[level:], package, level) File "", line 1006, in _gcd_import File "", line 983, in _find_and_load File "", l ine 965, in _find_and_load_unlocked ModuleNotFoundError: No module named 'main' 2020-06-20 06:51:09 default[20200620t115649] [2020-06-20 06:51:09 +0000] [18] [INFO] Worker exiting (pid: 18) 2020-06-20 06:51:09 default[20200620t115649] [2020-06-20 06:51:09 +0000] [22] [INFO] Booting worker with pid: 22 2020-06-20 06:51:09 default[20200620t115649] [2020-06-20 06:51:09 +0000] [22] [ERROR] Exception in worker process 2020-06-20 06:51:09 default[20200620t115649] Traceback (most recent call last): File "/env/lib/python3.7/site-packages/gunicorn/arbiter.py", line 583, in spawn_worker worker.init_process() File "/env/lib/python3.7/site-p ackages/gunicorn/workers/gthread.py", line 92, in init_process super().init_process() File "/env/lib/python3.7/site-packages/gunicorn/workers/base.py", line 119, in init_process self.load_wsgi() File "/env/lib/python 3.7/site-packages/gunicorn/workers/base.py", line 144, in load_wsgi self.wsgi = self.app.wsgi() File "/env/lib/python3.7/site-packages/gunicorn/app/base.py", line 67, in wsgi self.callable = self.load() File "/env/li b/python3.7/site-packages/gunicorn/app/wsgiapp.py", line 49, in load return self.load_wsgiapp() File "/env/lib/python3.7/site-packages/gunicorn/app/wsgiapp.py", line 39, in load_wsgiapp return util.import_app(self.app_u ri) File "/env/lib/python3.7/site-packages/gunicorn/util.py", line 358, in import_app mod = importlib.import_module(module) File "/opt/python3.7/lib/python3.7/importlib/__init__.py", line 127, in import_module return _bootstrap._gcd_import(name[level:], package, level) File "", line 1006, in _gcd_import File "", line 983, in _find_and_load File "", l ine 965, in _find_and_load_unlocked ModuleNotFoundError: No module named 'main' 2020-06-20 06:51:09 default[20200620t115649] [2020-06-20 06:51:09 +0000] [22] [INFO] Worker exiting (pid: 22) 2020-06-20 06:51:09 default[20200620t115649] Traceback (most recent call last): File "/env/lib/python3.7/site-packages/gunicorn/arbiter.py", line 209, in run self.sleep() File "/env/lib/python3.7/site-packages/gunicorn/a rbiter.py", line 357, in sleep ready = select.select([self.PIPE[0]], [], [], 1.0) File "/env/lib/python3.7/site-packages/gunicorn/arbiter.py", line 242, in handle_chld self.reap_workers() File "/env/lib/python3.7/sit e-packages/gunicorn/arbiter.py", line 525, in reap_workers raise HaltServer(reason, self.WORKER_BOOT_ERROR) gunicorn.errors.HaltServer: 2020-06-20 06:51:09 default[20200620t115649] 2020-06-20 06:51:09 default[20200620t115649] During handling of the above exception, another exception occurred: 2020-06-20 06:51:09 default[20200620t115649] 2020-06-20 06:51:09 default[20200620t115649] Traceback (most recent call last): File "/env/bin/gunicorn", line 10, in sys.exit(run()) File "/env/lib/python3.7/site-packages/gunicorn/app/wsgiapp.py", line 58, in run WSGIApplication("%(prog)s [OPTIONS] [APP_MODULE]").run() File "/env/lib/python3.7/site-packages/gunicorn/app/base.py", line 228, in run super().run() File "/env/lib/python3.7/site-packages/gunicorn/app/base.py", line 72, in run Arbiter(self).run() File "/env/lib/python3.7/site-packages/gunicorn/arbiter.py", line 229, in run self.halt(reason=inst.reason, exit_status=inst.exit_status) File "/env/lib/python3.7/site-packages/gun icorn/arbiter.py", line 342, in halt self.stop() File "/env/lib/python3.7/site-packages/gunicorn/arbiter.py", line 393, in stop time.sleep(0.1) File "/env/lib/python3.7/site-packages/gunicorn/arbiter.py", line 242, i n handle_chld self.reap_workers() File "/env/lib/python3.7/site-packages/gunicorn/arbiter.py", line 525, in reap_workers raise HaltServer(reason, self.WORKER_BOOT_ERROR) gunicorn.errors.HaltServer:

Bobby · Answer

Hi there,

I just came accross this quesiton.

What I could suggest for Django is to follow the steps here on how to Set Up Django with Nginx, and Gunicorn:

https://www.digitalocean.com/community/tutorials/how-to-set-up-django-with-postgres-nginx-and-gunicorn-on-ubuntu-16-04

Regarding the 502 error, this means that your backend service is not running so Nginx is failing to connect to the backend, for more information on how to troubleshoot the 502 error, I could suggest following the steps from this answer here:

https://www.digitalocean.com/community/questions/502-bad-gateway-nginx-2

Regards, Bobby

KFSys · Answer

The key issue here is the ModuleNotFoundError: No module named 'main'. This error typically occurs when Gunicorn cannot find the WSGI application module. Let’s fix this step by step: 1. Identify Your WSGI Application In a typical Django project, the WSGI application is defined in the wsgi.py file, usually located in the project folder (e.g., your_project_name/wsgi.py). Gunicorn needs to know where to find this file to run your app. Open your wsgi.py file and confirm it looks something like this: import os from django.core.wsgi import get_wsgi_application os.environ.setdefault('DJANGO_SETTINGS_MODULE', 'your_project_name.settings') application = get_wsgi_application() Replace your_project_name with your actual project name. 2. Fix Gunicorn’s App Module Configuration The main module error suggests Gunicorn is looking for the wrong app module. Update your app.yaml file to point to the correct WSGI application. Open your app.yaml file. Locate the entrypoint setting and update it to: entrypoint: gunicorn -b :$PORT your_project_name.wsgi Replace your_project_name with the actual name of your Django project directory (the folder that contains settings.py and wsgi.py). 3. Update the App Engine Deployment Redeploy your application with the corrected app.yaml file: gcloud app deploy 4. Verify Static Files Django does not serve static files in production by default. You need to configure your App Engine to serve static files correctly: Add Static File Configuration to app.yaml: Define your static files directory in settings.py: STATIC_ROOT = os.path.join(BASE_DIR, "staticfiles") Collect static files: python manage.py collectstatic Add a static files section to your app.yaml: handlers: - url: /static static_dir: staticfiles 5. Ensure Database Configuration App Engine may require a different database configuration. If you’re using PostgreSQL or Cloud SQL, ensure you’ve set up your database settings correctly. Update DATABASES in settings.py to point to your Cloud SQL instance, e.g.: DATABASES = { 'default': { 'ENGINE': 'django.db.backends.postgresql', 'NAME': 'your_db_name', 'USER': 'your_db_user', 'PASSWORD': 'your_db_password', 'HOST': '/cloudsql/your-project-id:your-region:your-instance-name', } }