Startup configuration-validation library for the ZB.MOM.WW SCADA family (OtOpcUa, MxAccessGateway, ScadaBridge). This is a library, not a service — the package is linked directly into the consuming application at build time. It extracts the IValidateOptions plumbing the three apps share — failure accumulation, rule primitives, bind+validate DI wiring, and pre-host preflight — so that domain-specific validation rules stay per-project and the boilerplate does not drift.

What's in the box

Type	Description
`OptionsValidatorBase<TOptions>`	Abstract `IValidateOptions<TOptions>`. Override `protected void Validate(ValidationBuilder v, TOptions o)` to declare failures; the base aggregates all failures and returns a single `ValidateOptionsResult`.
`ValidationBuilder`	Failure accumulator. Primitives: `Required`, `Port`, `HostPort`, `PositiveTimeSpan`, `OneOf`, `MinCount`, `RequireThat(bool, msg)`, `Add(msg)`. Properties: `Failures` (read), `IsValid`.
`ServiceCollectionExtensions`	`AddValidatedOptions<TOptions, TValidator>(IConfiguration config, string sectionPath)` — binds the section, registers the validator, and calls `ValidateOnStart()` in a single extension method. Returns `OptionsBuilder<TOptions>`.
`ConfigPreflight`	Pre-host raw-`IConfiguration` checker. Fluent API: `For(config)`, `.Require(key, predicate, reason)`, `.RequireValue(key)`, `.RequirePort(key)`, `.When(cond, block)`, `.ThrowIfInvalid()`.

Usage

1. Validator subclass

public sealed class ClusterOptionsValidator : OptionsValidatorBase<ClusterOptions>
{
    protected override void Validate(ValidationBuilder v, ClusterOptions o)
    {
        v.MinCount(o.SeedNodes, 2, "Cluster:SeedNodes");
        v.OneOf(o.Strategy, new[] { "keep-oldest" }, "Cluster:Strategy");
        v.PositiveTimeSpan(o.StableAfter, "Cluster:StableAfter");
    }
}

2. DI wiring

builder.Services.AddValidatedOptions<ClusterOptions, ClusterOptionsValidator>(
    builder.Configuration, "ScadaBridge:Cluster");

This binds ScadaBridge:Cluster, registers ClusterOptionsValidator, and enables ValidateOnStart — the app refuses to start if the section fails validation.

3. Pre-host preflight

ConfigPreflight.For(configuration)
    .Require("Node:Role", v => v is "Central" or "Site", "must be 'Central' or 'Site'")
    .RequirePort("Node:RemotingPort")
    .When(role == "Site", p => p.RequireValue("Node:SiteId"))
    .ThrowIfInvalid();

Use ConfigPreflight before WebApplication.CreateBuilder for critical keys (node role, remoting port, site ID) that must be present and valid before the DI container is even constructed.

Building and testing

# from ZB.MOM.WW.Configuration/
dotnet test ZB.MOM.WW.Configuration.slnx

All tests run with no external dependencies:

Assembly	Tests
`ZB.MOM.WW.Configuration.Tests`	27
Total	27

Packing

dotnet pack ZB.MOM.WW.Configuration.slnx -c Release -o ./artifacts

Produces one .nupkg file in artifacts/:

ZB.MOM.WW.Configuration.0.1.0.nupkg

GeneratePackageOnBuild is off — pack explicitly as above. Version is set in Directory.Build.props.

Dependencies

The package has a minimal closure — only Microsoft.Extensions.* abstractions:

Microsoft.Extensions.Options
Microsoft.Extensions.Options.ConfigurationExtensions
Microsoft.Extensions.Configuration.Abstractions
Microsoft.Extensions.DependencyInjection.Abstractions

No third-party packages; no ASP.NET Core framework reference.

Status

Built at 0.1.0. Not yet adopted by the three apps. Adoption is tracked in the component backlog:

~/Desktop/scadaproj/components/configuration/GAPS.md

Design documentation lives alongside that backlog:

~/Desktop/scadaproj/components/configuration/spec/SPEC.md — normalized validation target
~/Desktop/scadaproj/components/configuration/shared-contract/ZB.MOM.WW.Configuration.md — proposed API
~/Desktop/scadaproj/components/configuration/current-state/ — per-project current state (code-verified)