I was not able to find documentation about how to connect GCF with Google Cloud Endpoints. As I understand Google Cloud Endpoints can be configured to access internal cloud resources. It is not clear how to use load balancer with Endpoints service as well.
In the Building Scalable Web Apps with Cloud Datastore article it indicates that you should be able to configure a direct connection from Cloud Endpoints to Cloud Functions. There is no indication that you would need to have any Compute Engine or other infrastructure between them. Is there any documentation or tutorial on how to connect Cloud Endpoints to Cloud Functions? Did somebody manage to connect those two services?
At this time, there is no way to connect GCF with Endpoints. Sorry about that!
The pair of Google Cloud Endpoints and Google Cloud Functions and AWS API Gateway and AWS lambda are not same.
Google Cloud Endpoints monitor your existing API analytics and limits its usage via API Credentials.
So to link your Google Cloud Endpoints and Google Cloud Functions, you have to use Google App Engine or Google Compute Engine to connect them.
来源：https://stackoverflow.com/questions/44763173/google-cloud-endpoints-with-google-cloud-functions