feat(options): eager startup validation for Communication + DataConnectionLayer options (arch-review 08 §1.5)

Claude-Session: https://claude.ai/code/session_01MtdgwpEeCUn6cUA5f1LMPj

src/ZB.MOM.WW.ScadaBridge.DataConnectionLayer/DataConnectionOptionsValidator.cs

@@ -0,0 +1,39 @@
+using ZB.MOM.WW.Configuration;
+
+namespace ZB.MOM.WW.ScadaBridge.DataConnectionLayer;
+
+/// <summary>
+/// Validates <see cref="DataConnectionOptions"/> at startup (ValidateOnStart) so a
+/// malformed "DataConnectionLayer" appsettings section fails fast at boot with a
+/// key-naming message instead of surfacing later at runtime. The intervals drive
+/// the reconnect/tag-resolution timers and the seed-read retry loop; a
+/// zero/negative duration (or a non-positive <c>SeedReadMaxAttempts</c>) would
+/// otherwise produce an opaque failure far from the offending config key.
+/// </summary>
+public sealed class DataConnectionOptionsValidator : OptionsValidatorBase<DataConnectionOptions>
+{
+    /// <inheritdoc />
+    protected override void Validate(ValidationBuilder builder, DataConnectionOptions options)
+    {
+        builder.RequireThat(options.ReconnectInterval > TimeSpan.Zero,
+            $"DataConnectionLayer:ReconnectInterval must be a positive duration (was {options.ReconnectInterval}).");
+
+        builder.RequireThat(options.TagResolutionRetryInterval > TimeSpan.Zero,
+            $"DataConnectionLayer:TagResolutionRetryInterval must be a positive duration (was {options.TagResolutionRetryInterval}).");
+
+        builder.RequireThat(options.WriteTimeout > TimeSpan.Zero,
+            $"DataConnectionLayer:WriteTimeout must be a positive duration (was {options.WriteTimeout}).");
+
+        builder.RequireThat(options.SeedReadTimeout > TimeSpan.Zero,
+            $"DataConnectionLayer:SeedReadTimeout must be a positive duration (was {options.SeedReadTimeout}).");
+
+        builder.RequireThat(options.StableConnectionThreshold > TimeSpan.Zero,
+            $"DataConnectionLayer:StableConnectionThreshold must be a positive duration (was {options.StableConnectionThreshold}).");
+
+        builder.RequireThat(options.SeedReadRetryDelay > TimeSpan.Zero,
+            $"DataConnectionLayer:SeedReadRetryDelay must be a positive duration (was {options.SeedReadRetryDelay}).");
+
+        builder.RequireThat(options.SeedReadMaxAttempts > 0,
+            $"DataConnectionLayer:SeedReadMaxAttempts must be positive (was {options.SeedReadMaxAttempts}).");
+    }
+}

src/ZB.MOM.WW.ScadaBridge.DataConnectionLayer/ServiceCollectionExtensions.cs

@@ -1,4 +1,6 @@
 using Microsoft.Extensions.DependencyInjection;
+using Microsoft.Extensions.DependencyInjection.Extensions;
+using Microsoft.Extensions.Options;
 
 namespace ZB.MOM.WW.ScadaBridge.DataConnectionLayer;
 
@@ -13,8 +15,14 @@ public static class ServiceCollectionExtensions
     public static IServiceCollection AddDataConnectionLayer(this IServiceCollection services)
     {
         services.AddOptions<DataConnectionOptions>()
-            .BindConfiguration("DataConnectionLayer");
+            .BindConfiguration("DataConnectionLayer")
+            .ValidateOnStart();
+        services.TryAddEnumerable(
+            ServiceDescriptor.Singleton<IValidateOptions<DataConnectionOptions>, DataConnectionOptionsValidator>());
 
+        // OpcUaGlobalOptions / MxGatewayGlobalOptions carry only string identity/path
+        // fields (no numeric or duration knobs), so there is nothing to range-validate
+        // — no dedicated validator is registered for them.
         services.AddOptions<OpcUaGlobalOptions>()
             .BindConfiguration("OpcUa");
 

src/ZB.MOM.WW.ScadaBridge.DataConnectionLayer/ZB.MOM.WW.ScadaBridge.DataConnectionLayer.csproj

@@ -17,6 +17,7 @@
     <PackageReference Include="Microsoft.Extensions.Options.ConfigurationExtensions" />
     <PackageReference Include="OPCFoundation.NetStandard.Opc.Ua.Client" />
     <PackageReference Include="ZB.MOM.WW.MxGateway.Client" />
+    <PackageReference Include="ZB.MOM.WW.Configuration" />
   </ItemGroup>
 
   <ItemGroup>