Check whether deployed in cloud

Question

I have a python program running in a Docker container. My authentication method depends on whether the container is deployed in GCP or not. Ideally I'd have a function like this:

def deployment_environment():
    # return 'local' if [some test] else 'cloud'
    pass

What's the most idiomatic way of checking this? My instinct is to use env named [APP_NAME]_DEPLOYMENT_ENVIRONMENT which gets set either way -- but making sure this is set correctly has too many moving parts. Is there a GCP package/tool which can check for me?

Answer 1

There are two solutions I've arrived at:

With env

Set an env var when deploying, like so:

gcloud functions deploy [function-name] --set-env-vars ENV_GCP=1

Then, in your code:

import socket


def deployment_environment():
    return 'cloud' if ('ENV_GCP' in os.environ) else 'local'

Pros	Cons
intent is clear, both setting and using env	more involved
idiomatic	relies on user setting env correctly

Via Python, with Sockets

import socket


def deployment_environment():
    try:
        socket.getaddrinfo('metadata.google.internal', 80)
        return 'cloud'
    except socket.gaierror:
        return 'local'

Pros	Cons
more succinct	makes improper use of try/catch
doesn't rely on an extra step of setting env	dependency on socket package & GCP runtime contract