System calls with google cloud scheduler and python script

Question

I am trying to run a Python script via Cloud Scheduler every 5 minutes that checks the statuses of websites and starts/stops Google Cloud Compute instances.

The code is basically:

import requests
import os
import sys
import optmain

websites = {'espn':'https://www.espn.com/', 'fb':'https://www.facebook.com/'}

def auto_fix():
for x in websites:
     try:
       z = requests.get(websites[x], timeout=15)
     except: 
       optmain('restart', x)
auto_fix()

Thing is, the function optmain was this:

def optmain(option, instance):
    option = option.lower()
    instance = instance.lower()
    if option == 'restart':
        os.system('gcloud compute instances stop {}'.format(instance))
        time.sleep(100)
        os.system('gcloud compute instances start {}'.format(instance))

But I dont know if this will work if moved to Google Cloud Functions because of the system call for gcloud compute instances stop/start {instance}. I already tried putting this up in Cloud Scheduler and it failed. Yet again, I don't know if I even did that right. So can I please get some assistance here? I hope you get the jist of what I'm trying to accomplish, its very basic.

Answer 1

It's generally better to use the Python client library rather than shelling out to gcloud.

For example, to stop a Compute instance from a Cloud Function, you would add google-api-python-client to your requirements.txt and run something like:

from googleapiclient import discovery

service = discovery.build('compute', 'v1')

# Project ID for this request.
project = 'my-project'  # TODO: Update placeholder value.

# The name of the zone for this request.
zone = 'my-zone'  # TODO: Update placeholder value.

# Name of the instance resource to stop.
instance = 'my-instance'  # TODO: Update placeholder value.

request = service.instances().stop(project=project, zone=zone, instance=instance)
response = request.execute()