Support for EnvoyRateLimiter in Beam Python SDK

[tarun-google]

Please add a meaningful description for your change here

---

Thank you for your contribution! Follow this checklist to help us incorporate your contribution quickly and easily:

• Mention the appropriate issue in your description (for example: addresses #123), if applicable. This will automatically add a link to the pull request in the issue. If you would like the issue to automatically close on merging the pull request, comment fixes #<ISSUE NUMBER> instead.
• Update CHANGES.md with noteworthy changes.
• If this contribution is large, please file an Apache Individual Contributor License Agreement.

See the Contributor Guide for more tips on how to make review process smoother.

To check the build health, please visit https://github.com/apache/beam/blob/master/.test-infra/BUILD_STATUS.md

GitHub Actions Tests Status (on master branch)

See CI.md for more information about GitHub Actions CI or the workflows README to see a list of phrases to trigger workflows.

[gemini-code-assist]

Summary of Changes

Hello @tarun-google, I'm Gemini Code Assist¹! I'm currently reviewing this pull request and will post my feedback shortly. In the meantime, here's a summary to help you and other reviewers quickly get up to speed!

This pull request enhances the Apache Beam Python SDK by introducing robust support for external rate limiting using an Envoy Rate Limit Service. The core addition is the "EnvoyRateLimiter" class, which allows Beam pipelines to gracefully handle rate limits when interacting with external APIs or resources. This feature is crucial for preventing service overload and ensuring stable pipeline execution by dynamically adjusting the processing rate based on external signals. The implementation includes retry mechanisms for both connection failures and "OVER_LIMIT" responses, along with detailed metrics for monitoring.

Highlights

• New EnvoyRateLimiter: Introduced a new "EnvoyRateLimiter" class in the Beam Python SDK to enable external rate limiting via an Envoy Rate Limit Service (RLS).
• Abstract RateLimiter Base Class: Added an abstract "RateLimiter" base class, providing a common interface for future rate limiting implementations.
• Metrics Integration: The "EnvoyRateLimiter" collects various metrics, including total requests, allowed requests, throttled requests, RPC errors, retries, and RPC latency, providing visibility into rate limiting behavior.
• Shared Instance Management: Utilizes Beam's "shared.Shared()" utility to ensure that only a single "EnvoyRateLimiter" instance is created per worker and shared across threads, optimizing resource usage.
• Example and Tests: Includes a new example pipeline ("rate_limiter_simple.py") demonstrating how to integrate the "EnvoyRateLimiter" into a "DoFn", along with comprehensive unit tests for the new functionality.
• Dependency Update: Added "envoy-data-plane" to "setup.py" to support communication with the Envoy RLS.

Using Gemini Code Assist

The full guide for Gemini Code Assist can be found on our documentation page, here are some quick tips.

Invoking Gemini

You can request assistance from Gemini at any point by creating a comment using either /gemini <command> or @gemini-code-assist <command>. Below is a summary of the supported commands on the current page.

Feature	Command	Description
Code Review	/gemini review	Performs a code review for the current pull request in its current state.
Pull Request Summary	/gemini summary	Provides a summary of the current pull request in its current state.
Comment	@gemini-code-assist	Responds in comments when explicitly tagged, both in pull request comments and review comments.
Help	/gemini help	Displays a list of available commands.

Customization

To customize Gemini Code Assist for GitHub experience, repository maintainers can create a configuration file and/or provide a custom code review style guide (such as PEP-8 for Python) by creating and adding files to a .gemini/ folder in the base of the repository. Detailed instructions can be found here.

Limitations & Feedback

Gemini Code Assist may make mistakes. Please leave feedback on any instances where its feedback is incorrect or counter productive. You can react with 👍 and 👎 on @gemini-code-assist comments. If you're interested in giving your feedback about your experience with Gemini Code Assist for Github and other Google products, sign up here.

You can also get AI-powered code generation, chat, as well as code reviews directly in the IDE at no cost with the Gemini Code Assist IDE Extension.

Footnotes

1. Review the Privacy Notices, Generative AI Prohibited Use Policy, Terms of Service, and learn how to configure Gemini Code Assist in GitHub here. Gemini can make mistakes, so double check it and use code with caution. ↩