Comparing Extensible Service Proxy and Endpoints Frameworks

This document explains the differences between Cloud Endpoints Frameworks and the Extensible Service Proxy, which is used in Cloud Endpoints for APIs using OpenAPI or gRPC.

Overview

Cloud Endpoints is a set of technologies that provides end-to-end API management: from writing and serving your API, through securing it and monitoring it at runtime.

Cloud Endpoints API management includes authentication, API keys, monitoring, logging and tracing independent of the technology used to implement the API. Management functionality is provided through the Extensible Service Proxy or by using the Endpoints Frameworks in Java or Python.

Extensible Service Proxy

In Cloud Endpoints for OpenAPI and gRPC, API requests are relayed through the Extensible Service Proxy (ESP), which validates keys and authentication tokens and sends signals (metrics and logs) via the Google Service Control API. The separation provided by ESP means that you can write the REST or gRPC backend code in any language, and you can use gRPC or any framework that supports API description using OpenAPI.

  • APIs using OpenAPI: The API backend can run on the App Engine flexible environment, Google Kubernetes Engine, Compute Engine, Kubernetes, or on-premises deployments.

  • APIs using gRPC: The API backend can run on Kubernetes Engine, Compute Engine, Kubernetes, or on-premises deployments.

ESP architecture

A request is sent on the following path:

  1. A request to your code is received and is sent to ESP.
  2. ESP sends a check request to Service Control.
  3. If you configured your API to require an API key or authentication, Service Control checks to see if the request is permitted and sends a response back to ESP.
  4. If the request is not permitted, ESP rejects the request. If the request is permitted, it is forwarded to your backend code. Either way, ESP logs information about the request.

Pricing of Cloud Endpoints API management depends on the number of calls per month.

Endpoints Frameworks

For API backends running on the App Engine standard environment, Endpoints Frameworks is available to help developers quickly get started serving an API. Endpoints Frameworks is an alternative to Python Flask or Java Jersey. Endpoints Frameworks integrates with Service Control API, meaning a backend that uses Endpoints Frameworks does not need to run behind the Extensible Service Proxy.

Deploying a service management configuration will result in Endpoints Frameworks calling the Endpoints Management module at runtime for monitoring, logging, and API key validation.

Endpoints Frameworks

A request is sent on the following path:

  1. A request to your code is received and is sent to the Endpoints Management module.
  2. If you have enabled API Management by deploying your API configuration, the Endpoints Management module sends a check request to Service Control.
  3. If you configured your API to require an API key or authentication, Service Control checks to see if the request is permitted and sends a response back to the Endpoints Management module.
  4. If the request is not permitted, the Endpoints Management module rejects the request. If the request is permitted, it is forwarded to the Endpoints Framework. Either way, the Endpoints Management module logs information about the request.
  5. The request is forwarded to your backend code.

Endpoints Frameworks can be used with or without API management functionality. Use of Endpoints Frameworks without API management functionality is offered at no charge. API management functionality is charged according to the Cloud Endpoints pricing page.

Endpoints Frameworks is supported only for services running on the App Engine standard environment. On Compute Engine, Kubernetes Engine, App Engine flexible environment, or other environments, your services must run behind the Extensible Service Proxy.

If the service is running behind the Extensible Service Proxy, the backend code can be written in any language and framework, such as Python Flask, Java Jersey, Node.JS Express. In such environments, there is no need to use Endpoints Frameworks for API management.

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Cloud Endpoints Frameworks for App Engine