[Google Maps Places Client] - Add the ability to impersonate a service account

[shaunmitchellve]

A screenshot that you have tested with "Try this API".

What would you like to see in the library?

When using the PlacesClient with Application Default Credentials the client works fine.

When you setup ADC with Service Account Impersonation then the client error's out with a Getting metadata from plugin failed with error: INVALID_ARGUMENT: unable to impersonate: Request contains an invalid argument. error.

I'm assuming that the client is setup to utilize the impersonation credentials properly from the ~/.conifg/gcloud/application_default_credentials.json file. The structure is different depending on if using your own Google account vs impersonating a service account.

Describe alternatives you've considered

I've tried overriding the Place Client client options with an Auth client that uses an API Key. I wasn't able to get the API Key approach to work either.

Additional context/notes

No response

[shaunmitchellve]

I was able to resolve this by manually setting the scopes in the Places Client.

import {PlacesClient} from '@googlemaps/places';
const placesClient = new PlacesClient({
    scopes: ['https://www.googleapis.com/auth/cloud-platform']
 });

It would appear that the Google Map Places Client doesn't set any auth scopes by default:

places_client.js:263

static get scopes() {
        return [];
}

I would suggest at least adding in the default scope of 'https://www.googleapis.com/auth/cloud-platform'.