Implement new GCS Cache adapter that uses Google Cloud SDKs auth discovery defaults
What does this MR do?
Implements a GCS Cache Adapter "v2" that uses the Google cloud storage SDK to provide authentication discovery, rather than rolling our own as the original (now "legacy") adapter uses.
We don't expect any breaking changes here, so the new flag FF_USE_LEGACY_GCS_CACHE_ADAPTER will be disabled by default. Should customers encounter issues, FF_USE_LEGACY_GCS_CACHE_ADAPTER: true will enable the older adapter.
Why was this MR needed?
In certain environments, such as GKE with Workload Identity enabled, authentication was not working as expected.
The Google Cloud storage SDK provides discovery of credentials in a number of environments, so we shouldn't need to write our own methods.
What's the best way to test this MR?
- Test any existing GCS Cache configuration and it should continue to work as it previously did.
- Confirm with customers that Workload Identity is now working as expected.