support for kubernetes secrets type in auth_modules for Multi-Target Support (BETA)

I am currently using the Multi-Target Support feature in the postgres_exporter to scrape metrics from multiple Postgres instances deployed in my Kubernetes cluster. The exporter is configured using a scrape job as mentioned in the Muti-Target Support feature docs.

The Muti-Target Support feature currently supports preconfigured auth_modules as way of authenticating to the postgres instances. But the auth_modules only supports the userpass type. I would like to request the support for Kubernetes secrets in the auth_module, allowing users to securely store and manage database credentials in Kubernetes secrets for multiple Postgres instances rather than hardcoding user and password values in the configuration..

Potential Implementation

• Allow the auth_module to reference a Kubernetes secret by name.

Versions

Postgres Exporter - v0.15.0
Kubernetes - v1.28.4

Thank you for considering this feature request!

Start with the Multi-Target Support documentation and the existing auth_modules configuration described there, focusing on how the userpass type is handled. Define the expected Kubernetes secret reference behavior for multiple Postgres instances and verify that the completed feature lets users avoid hardcoding database credentials.