[RSS Phase 2] DIRAC legacy integration

[aldbr]

Goal

DIRAC's ResourceStatus and SiteStatus singletons consume resource status from diracx instead of the legacy RSS RPC service. Once this phase is complete, the legacy RSS read path will be deprecated.

Consumers

Two singleton helpers wrap ResourceStatusClient (RPC) with a 300s in-memory cache:

• ResourceStatus — returns status for Storage Elements (4 access types), Computing Elements, and FTS. Used by StorageFactory, SiteDirector, FTS3Utilities, admin scripts, and others.
• SiteStatus — returns site availability. Used by SiteDirector, JobScheduling, Matcher, and others.

Both also expose write methods used by admin scripts and agents. All consumers go through the singletons, so migrating the singletons' backend is transparent to them.

Sub-issues

graph LR
    A[A. Adapt DIRAC consumers<br/>to binary status model] --> C[C. Custom read adapter<br/>+ feature flag + tests]
    B[B. Response format<br/>translation layer] --> C

    style A fill:#c3e6cb
    style B fill:#c3e6cb

Loading

Green = can start once phase 1 is merged (parallel, independent).

• A. Adapt DIRAC consumers to the binary status model
• B. Response format translation layer
• C. Feature flag + integration tests