When using Cloud SQL Proxy to connect a Compute Engine application to Cloud SQL, which role should be assigned for minimum access?

The Cloud SQL Client role is specifically designed to provide the necessary permissions for applications to connect to and interact with Cloud SQL instances while ensuring minimal access. This role includes permissions to connect to the Cloud SQL database instances, which is crucial when using Cloud SQL Proxy to establish a connection from a Compute Engine application.

By using the Cloud SQL Client role, you limit the permissions to just what is required for the application to function without granting excess privileges. This principle of least privilege is essential in cloud security, as it minimizes the risk of unauthorized access or actions that could potentially compromise the database or the overall project.

In contrast, the Project Editor and Project Owner roles provide broader access than necessary for just connecting to Cloud SQL, including permissions to modify resources across the entire project. The Cloud SQL Editor role, while more limited than Owner or Editor roles, still gives permissions to modify SQL instances, which would exceed the requirements for a simple connection. Therefore, the Cloud SQL Client role is the most appropriate choice for ensuring a secure and efficient connection to Cloud SQL with the least amount of access needed.