Is a Service Account intended to be created in an application’s domain? Or in a clients G Suite Domain, on behalf of the application?
Background:
My company has a product (hereafter “The App”) which has several thousand organizations as clients, each potentially having their own Google domains. (hereafter “Organization Domain”)
We are looking to set up a sync between The App and the Organization Domain, for data that is common between The App and the Organization Domain, and want to use an OAuth2 connection, with a domain admin granting The App ‘domain-wide authority’ on behalf of their users, for offline syncing.
From the Service Account page:
... an account that belongs to your application instead of to an individual end user. Your application calls Google APIs on behalf of the service account, so users aren't directly involved.
and
G Suite domain administrators can also grant service accounts domain-wide authority to access user data on behalf of users in the domain.
Referencing the Cloud Platform Console Help Faq:
You can access data from your users' Google Cloud Platform projects by creating a service account to represent your service, and then having your customers grant that service account appropriate access to their cloud data using IAM policies. Note that you might want to create a service account per customer... (emphasis added)
It sounds like The App should be able to create a single Service Account, which all of our clients authenticate into for their Organization Domain.
The part that’s unclear:
In the Service Account page, the instructions for delegating domain wide authority seems to shift concerning where the Service Account is.
Before the instructions, it reads:
... first enable domain-wide delegation for an existing service account in the Service accounts page ... with domain-wide delegation enabled. Then, an administrator of the G Suite domain must complete the following steps:
Afterwards, it reads
Your application now has the authority to make API calls as users in your domain (to "impersonate" users). (emphasis added)
From what I’m reading, the first part reads "one Service Account for The App", while the later reads as "the service account is only able to access as a person on The App domain, rather than the Organization Domain."
Is a service account intended to be created in The App's domain? Or in the Organization Domain, on behalf of The App?
I have seen examples that have the Organization Domain admin create a service account, and then pass over the clientID/secret to the owners of The App… but I’m not sure that’s the correct approach for our scenario.
Related - Scope management: The delegation steps have the Organization Domain admin manually add scopes.
We’d prefer to use the OAuth consent screen, which shows the scopes, and has our pages/policies linked. Unfortunately, as far as my research has uncovered, it doesn’t look like that page is used in the Service Account authorization flow; just for other application types, which authenticate a single user, as opposed to an entire Organization Domain.
Is there a page I’ve missed in Google’s sea of documentation?
