Google Cloud SQL-操作系统环境未设置为Google App Engine

Question

I am attempting to connected to a Google Cloud SQL instance in python and have gone through google's tutorial: https://cloud.google.com/appengine/docs/python/cloud-sql/

I am essentially cloning google's tutorial code and for some reason this line isn't working right for me:

if (os.getenv('SERVER_SOFTWARE') and
  os.getenv('SERVER_SOFTWARE').startswith('Google App Engine/')):

This if statement is not being entered and I'm not sure why - it is then defaulting to accessing a local database based on the else statement. How is the os server_software environment set? I'm new to all of this but basically because that is not getting set, I am not able to access my google cloud sql instance. How do I make sure this if statement is entered?

Answer 1

SERVER_SOFTWARE is an environment variable that is automatically set by GAE. It could either be something like Google App Engine/xxxx when deployed or Development/xx when running locally.

Basically the section of the code you're referring to checks whether your app is deployed and is running on GAE servers and if so - it will connect to a Google Cloud SQL instance, otherwise, if your app is running locally, it will attempt to connect to a local mysql instance.

It's done that way because you wouldn't normally want to mess with your production (deployed) data while developing & testing locally as many thing could go wrong.

Since you're stating that the if statement is not being entered - it's safe to assume that you are trying to run the program locally but are expecting it to connect to a Google Cloud SQL instance, for that, the next few lines in the example you provided are explaining how to do it:

db = MySQLdb.connect(host='127.0.0.1', port=3306, db='guestbook', user='root', charset='utf8')
# Alternatively, connect to a Google Cloud SQL instance using:
# db = MySQLdb.connect(host='ip-address-of-google-cloud-sql-instance', port=3306, user='root', charset='utf8')

so what you need to do is comment out the first line (the one it attempts to connect to a localhost mysql server) and uncomment the one where it connects to the Google Cloud SQL instance (note that you will have to update several parameters that reflect the configuration that you have, ie the host parameter and possible others).