When developing an application with PostgreSQL on Cloud Run, what is crucial for keeping traffic private?

When developing an application using PostgreSQL on Cloud Run, maintaining private traffic between your services is paramount. Enabling Cloud SQL and Cloud Run in the same project is crucial for this purpose because it facilitates the management of resources and connections within a single networking environment. This setup allows you to take advantage of Google's private IP capabilities, ensuring that the communication between your application hosted on Cloud Run and your PostgreSQL database remains secure and isolated from the public internet.

Not only does this configuration help simplify permissions and access controls, but it also reduces latency since the two services can communicate over the internal network. By keeping both components within the same project, you leverage Google Cloud's built-in security features designed to minimize risks associated with exposure to external traffic.

In contrast, deploying PostgreSQL on a Compute Engine VM can expose your database to the public internet if not configured correctly, and using a Serverless VPC Access connector serves a different purpose—primarily connecting serverless environments to a VPC, rather than ensuring both services reside in a shared secure context. Finally, using Cloud SQL and Cloud Run in different projects would likely complicate access and could lead to increased latency and security vulnerabilities, violating the principle of keeping private traffic within a contained environment. Thus, option A effectively