feat(iam): Support the mTLS IAM domain for Certificate based Access

[amtk3]

Update the IAM endpoint so that it supports the certificate based Access control

[gemini-code-assist]

Summary of Changes

Hello @amtk3, 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 IAM authentication mechanism by integrating support for mTLS (mutual TLS) endpoints. The primary goal is to enable certificate-based access control for IAM credential operations, which is crucial for environments requiring heightened security and compliance. The changes involve dynamically determining whether to use the mTLS-specific IAM domain based on client certificate availability, thereby ensuring that the correct secure endpoint is utilized for authentication requests.

Highlights

• mTLS Support: Introduced logic to dynamically select between the standard IAM credentials domain (iamcredentials.googleapis.com) and the mTLS-specific domain (iamcredentials.mtls.googleapis.com) based on the availability of client certificates.
• Dependency Addition: Added an import for _mtls_helper from google.auth.transport to facilitate the detection of mTLS client certificate usage.
• Endpoint Refactoring: Refactored the definition of various IAM endpoints (_IAM_ENDPOINT, _IAM_SIGN_ENDPOINT, _IAM_SIGNJWT_ENDPOINT, _IAM_IDTOKEN_ENDPOINT) to use a common base URL, which is constructed dynamically with the chosen domain.

🧠 New Feature in Public Preview: You can now enable Memory to help Gemini Code Assist learn from your team's feedback. This makes future code reviews more consistent and personalized to your project's style. Click here to enable Memory in your admin console.

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. ↩

[gemini-code-assist]

Code Review

This pull request updates the IAM endpoints to support mTLS by dynamically selecting the domain based on certificate availability. The changes are well-structured, centralizing the endpoint construction and improving code clarity by removing repetition. I have one minor suggestion regarding code style to align with PEP 8 guidelines.

[agrawalradhika-cell]

Can refer - https://github.com/googleapis/gapic-generator-python/pull/2472/changes

[chalmerlowe]

LGTM