Django Google App Engine Server Error 500 - mysql

Question

I have deployed my Django app to Google Cloud. It worked fine when I hosted it locally and throughout the steps outlined in this post.
It raises a server Error(500) when I try to view the live link.
When I enable Debug in the settings.py, this is the full traceback. (Torque is the name of my project), and showroom is my app.
The traceback refers to a views attribute (num_manufactureres) which I never had a problem with when hosting it locally.
OperationalError at /showroom/
(2002, "Can't connect to local MySQL server through socket '/var/run/mysqld/mysqld.sock' (2)")
Request Method: GET
Request URL: https://torque-256805.appspot.com/showroom/
Django Version: 2.2.5
Exception Type: OperationalError
Exception Value:
(2002, "Can't connect to local MySQL server through socket '/var/run/mysqld/mysqld.sock' (2)")
Exception Location: /env/lib/python3.7/site-packages/MySQLdb/connections.py in __init__, line 166
Python Executable: /env/bin/python3.7
Python Version: 3.7.4
Python Path:
['/srv',
'/env/bin',
'/opt/python3.7/lib/python37.zip',
'/opt/python3.7/lib/python3.7',
'/opt/python3.7/lib/python3.7/lib-dynload',
'/env/lib/python3.7/site-packages']
Server time: Thu, 24 Oct 2019 09:45:29 +0300
...
/env/lib/python3.7/site-packages/MySQLdb/__init__.py in Connect
return Connection(*args, **kwargs) …
▶ Local vars
/env/lib/python3.7/site-packages/MySQLdb/connections.py in __init__
super(Connection, self).__init__(*args, **kwargs2) …
▶ Local vars
...
num_manufacturers = Manufacturer.objects.all().count() …
▶ Local vars
I'm new to Google Cloud, so I don't know how to start debugging this.
Here are some possible issues:
The server instance I created on the cloud.google.com uses europe-west3 as a region. But when I was deploying, I thought that it created a completely new server and chose europe-west6 as a better option. (Close proximity, better reliability etc...)
I changed my project settings.py for better security according to the check --deploy Django command.
Otherwise, I can't think of anything else. Can anyone help?

Answer 1

Check out this Django example on App Engine settings.py file:
if os.getenv('GAE_APPLICATION', None):
# Running on production App Engine, so connect to Google Cloud SQL using
# the unix socket at /cloudsql/<your-cloudsql-connection string>
DATABASES = {
'default': {
'ENGINE': 'django.db.backends.mysql',
'HOST': '/cloudsql/[YOUR-CONNECTION-NAME]',
'USER': '[YOUR-USERNAME]',
'PASSWORD': '[YOUR-PASSWORD]',
'NAME': '[YOUR-DATABASE]',
}
}
else:
# Running locally so connect to either a local MySQL instance or connect to
# Cloud SQL via the proxy. To start the proxy via command line:
#
# $ cloud_sql_proxy -instances=[INSTANCE_CONNECTION_NAME]=tcp:3306
#
# See https://cloud.google.com/sql/docs/mysql-connect-proxy
DATABASES = {
'default': {
'ENGINE': 'django.db.backends.mysql',
'HOST': '127.0.0.1',
'PORT': '3306',
'NAME': '[YOUR-DATABASE]',
'USER': '[YOUR-USERNAME]',
'PASSWORD': '[YOUR-PASSWORD]',
}
}
Last but not least, if you're running your app locally, make sure you have ALLOWED_HOSTS= ['localhost'] if your database host is HOST='localhost', or else you can just use 'HOST': '127.0.0.1', as shown in the code sample above.