feat(controlplane): ServiceLevelCalculator + ControlPlane.Tests harness

src/Server/ZB.MOM.WW.OtOpcUa.ControlPlane/Redundancy/ServiceLevelCalculator.cs

@@ -0,0 +1,40 @@
+using Akka.Cluster;
+
+namespace ZB.MOM.WW.OtOpcUa.ControlPlane.Redundancy;
+
+public readonly record struct NodeHealthInputs(
+    MemberStatus MemberState,
+    bool DbReachable,
+    bool OpcUaProbeOk,
+    bool Stale,
+    bool IsDriverRoleLeader);
+
+/// <summary>
+/// Pure ServiceLevel computation per design §6. Output range 0–255, where higher = "more
+/// authoritative." The OPC UA SDK exposes this as the node's <c>ServiceLevel</c> Variable and
+/// redundant clients use it to pick which server to subscribe to.
+///
+/// Tiering:
+/// - Member not Up/Joining: 0 (cluster cannot trust this node).
+/// - DB reachable + OPC UA probe ok + not stale: 240 (full service).
+/// - Stale config (DB reachable or not, OPC UA probe state ignored): 100 or 200 depending on DB.
+/// - +10 bonus when this node holds the role-leader lease for the "driver" role.
+/// </summary>
+public static class ServiceLevelCalculator
+{
+    public static byte Compute(NodeHealthInputs h)
+    {
+        if (h.MemberState is not (MemberStatus.Up or MemberStatus.Joining))
+            return 0;
+
+        var basis = (h.DbReachable, h.OpcUaProbeOk, h.Stale) switch
+        {
+            (true,  true,  false) => 240,
+            (true,  _,     true)  => 200,
+            (false, _,     true)  => 100,
+            _ => 0,
+        };
+
+        return (byte)Math.Clamp(basis + (h.IsDriverRoleLeader ? 10 : 0), 0, 255);
+    }
+}

src/Server/ZB.MOM.WW.OtOpcUa.ControlPlane/ZB.MOM.WW.OtOpcUa.ControlPlane.csproj

@@ -11,7 +11,10 @@
 
     <ItemGroup>
         <PackageReference Include="Akka.Hosting"/>
+        <PackageReference Include="Akka.Cluster"/>
+        <PackageReference Include="Akka.Cluster.Hosting"/>
         <PackageReference Include="Akka.Cluster.Tools"/>
+        <PackageReference Include="Microsoft.EntityFrameworkCore"/>
     </ItemGroup>
 
     <ItemGroup>