Add support for GCP compatible Sovereign cloud (S3NS/Thales)

[zodd3131]

Feature Request: S3NS Artifact Registry Support in FluxCD

Overview

This proposal suggests adding support for S3NS Artifact Registry in FluxCD

Such an integration would enable teams using google sovereign cloud to fully leverage FluxCD’s GitOps capabilities for managing and deploying applications on GKE clusters.

Use Case

Many organizations must rely on sovereign cloud to protect their data and Google Cloud initiated Trusted Partner Cloud to allow new operators to offer google cloud services to their country.
For the moment, it fails with error message : failed to get credential from 'gcp': failed to parse artifact repository 'docker.s3nsregistry.fr/s3ns/dsna-shared-registry-0/shared-registry': invalid GCP registry: 'docker.s3nsregistry.fr'. must match ^(((.+\.)?gcr\.io)|(.+-docker\.pkg\.dev))$
Native support in FluxCD would allow:

Seamless GitOps workflows on S3NS as well in GCP
Consistent deployment practices across environments

Proposed Features

1. Modify regex to detect google/s3ns registry
   ^(((.+\.)?gcr\.io)|(.+-docker\.pkg\.dev))$ must now allow docker.s3nsregistry.fr/s3ns

2. Support for GOOGLE_CLOUD env variable GOOGLE_CLOUD_UNIVERSE_DOMAIN

3. Workload Identity Federation Authentication

Broader Adoption

Support for S3NS can help expand FluxCD adoption among S3NS users.

Conclusion

Adding support for S3NS would enhance FluxCD’s multi-cloud capabilities and provide meaningful value to teams operating on sovereign cloud.