It took me some time to figure and I can say that there is no way to set CORS origins in google UI. So we will have to install gem inside our API project and deploy changes to google cloud:
Add gem 'rack-cors' to gem file
Bundle install
Add following to application.rb:
config.middleware.insert_before 0, Rack::Cors do
allow do
origins '*'
resource '*', headers: :any, methods: :any
end
end
Don't forget to update '*' before deploying to production.
