fix(secrets): Grpc hub server review follow-ups — GetSecrets batch cap, DI single-registration guard + tests

Five review items on the Task 2 server half. 1. GetSecrets now enforces a server-side cap on request.Names, refusing an over-cap batch with ResourceExhausted BEFORE any store read runs. The well-behaved follower chunks at 500, but client discipline is not a server defence — the family precedent (HistorianGateway's max_values) is that the server declines regardless. The new SecretsGrpcHubServerOptions. MaxNamesPerRequest defaults to 1000, comfortably above that chunk so a compliant sweep never meets it, and Validate() refuses a non-positive value at startup rather than letting it read at runtime as a broken follower. The refusal states the cap and the received count — neither is secret, and an operator cannot resize a batch without them — and never a name. The cap sits behind the interceptor, so it is defence in depth against a misbehaving token holder, not an anonymous-DoS control. 2. AddZbSecretsGrpcHub now refuses a second registration. The two calls do not compose: options binding MERGES (a key absent from the second section leaves the first section's value standing) while the SectionPath stamp is last-one-wins, so a hub registered twice could serve a token bound from one section while every failure message named the other. Detected via a private marker registration. The extension also gains real DI coverage — the intended single-call path asserted for token/SectionPath coherence through a built provider, a custom section path stamped end to end, a missing token throwing from the registration call itself, and the duplicate call throwing. 3. Client-streaming and duplex-streaming denial tests, so all four gated handler shapes are pinned rather than only unary and server-streaming, plus a valid-token test that reaches all three streaming continuations. 4. A cancellation test: GetSecrets hands the ServerCallContext token through to the store, pinned against a fake that records it. 5. The proto's service comment stated the ISecretReplicationHub mapping in prose that no longer matched the RPC name; it now says GetManifestAsync -> GetManifest and GetManyAsync -> GetSecrets explicitly. Comment-only — no message or rpc definition is touched. The GetSecrets rpc comment also notes the new RESOURCE_EXHAUSTED cap, which a client author has to know about. Grpc server suite 50 -> 73 tests; full solution suite green, 0 new warnings. Claude-Session: https://claude.ai/code/session_014WNM4vjoVksyyBraTXSZE1
2026-08-07 06:27:16 -04:00
parent 7fc77f2790
commit 353af72265
7 changed files with 531 additions and 15 deletions
@@ -1,3 +1,8 @@
+using Microsoft.Extensions.Configuration;
+using Microsoft.Extensions.DependencyInjection;
+using Microsoft.Extensions.Options;
+using ZB.MOM.WW.Secrets.Replicator.Grpc.DependencyInjection;
+
 namespace ZB.MOM.WW.Secrets.Replicator.Grpc.Tests;

 /// <summary>
@@ -71,4 +76,194 @@ public sealed class SecretsGrpcHubServerOptionsTests

        Assert.Equal("Secrets:GrpcHub", options.SectionPath);
    }
+
+    [Fact]
+    public void Max_names_per_request_defaults_above_the_followers_own_fetch_chunk()
+    {
+        // The follower chunks at 500; the cap sits above that so a compliant sweep never meets it,
+        // and meeting it therefore means something.
+        var options = new SecretsGrpcHubServerOptions();
+
+        Assert.Equal(1000, options.MaxNamesPerRequest);
+    }
+
+    [Theory]
+    [InlineData(0)]
+    [InlineData(-1)]
+    [InlineData(int.MinValue)]
+    public void Validate_rejects_a_nonpositive_request_cap(int cap)
+    {
+        var options = new SecretsGrpcHubServerOptions
+        {
+            BearerToken = "a-configured-hub-token",
+            MaxNamesPerRequest = cap,
+        };
+
+        InvalidOperationException error =
+            Assert.Throws<InvalidOperationException>(() => options.Validate());
+
+        Assert.Contains("Secrets:GrpcHub:MaxNamesPerRequest", error.Message, StringComparison.Ordinal);
+    }
+
+    [Fact]
+    public void Validate_accepts_a_cap_of_one()
+    {
+        var options = new SecretsGrpcHubServerOptions
+        {
+            BearerToken = "a-configured-hub-token",
+            MaxNamesPerRequest = 1,
+        };
+
+        options.Validate();
+    }
+
+    [Fact]
+    public void Validate_names_the_section_path_on_the_request_cap_too()
+    {
+        var options = new SecretsGrpcHubServerOptions
+        {
+            BearerToken = "a-configured-hub-token",
+            MaxNamesPerRequest = 0,
+        };
+        options.SectionPath = "Central:Secrets:Hub";
+
+        InvalidOperationException error =
+            Assert.Throws<InvalidOperationException>(() => options.Validate());
+
+        Assert.Contains("Central:Secrets:Hub:MaxNamesPerRequest", error.Message, StringComparison.Ordinal);
+    }
+}
+
+/// <summary>
+/// The registration extension itself, driven through a real <see cref="ServiceCollection"/> and a
+/// real <see cref="IConfiguration"/>. What is pinned here is the coherence of what a host ends up
+/// holding: the token it configured, bound from the section it named, reported under that same
+/// section path — and the refusal of a second registration, which cannot deliver that coherence.
+/// </summary>
+public sealed class SecretsGrpcHubServerExtensionsTests
+{
+    private const string Token = "a-configured-hub-token";
+
+    [Fact]
+    public void Registration_binds_the_token_and_stamps_the_default_section_path()
+    {
+        var services = new ServiceCollection();
+
+        services.AddZbSecretsGrpcHub(Configuration(("Secrets:GrpcHub:BearerToken", Token)));
+
+        SecretsGrpcHubServerOptions options = Resolve(services);
+        Assert.Equal(Token, options.BearerToken);
+        Assert.Equal("Secrets:GrpcHub", options.SectionPath);
+        Assert.Equal(1000, options.MaxNamesPerRequest);
+    }
+
+    [Fact]
+    public void Registration_binds_the_request_cap_when_configured()
+    {
+        var services = new ServiceCollection();
+
+        services.AddZbSecretsGrpcHub(Configuration(
+            ("Secrets:GrpcHub:BearerToken", Token),
+            ("Secrets:GrpcHub:MaxNamesPerRequest", "250")));
+
+        Assert.Equal(250, Resolve(services).MaxNamesPerRequest);
+    }
+
+    [Fact]
+    public void Registration_under_a_custom_section_path_binds_and_stamps_that_path()
+    {
+        var services = new ServiceCollection();
+
+        services.AddZbSecretsGrpcHub(
+            Configuration(("Central:Secrets:Hub:BearerToken", Token)),
+            "Central:Secrets:Hub");
+
+        SecretsGrpcHubServerOptions options = Resolve(services);
+        Assert.Equal(Token, options.BearerToken);
+        Assert.Equal("Central:Secrets:Hub", options.SectionPath);
+    }
+
+    [Fact]
+    public void Registration_under_a_custom_section_path_names_that_path_when_the_token_is_missing()
+    {
+        // End to end: the operator is told the key THIS host reads, not the library's default.
+        var services = new ServiceCollection();
+
+        InvalidOperationException error = Assert.Throws<InvalidOperationException>(
+            () => services.AddZbSecretsGrpcHub(
+                Configuration(("Secrets:GrpcHub:BearerToken", Token)), "Central:Secrets:Hub"));
+
+        Assert.Contains("Central:Secrets:Hub:BearerToken", error.Message, StringComparison.Ordinal);
+    }
+
+    [Fact]
+    public void Registration_without_a_token_throws_naming_the_exact_key()
+    {
+        var services = new ServiceCollection();
+
+        InvalidOperationException error = Assert.Throws<InvalidOperationException>(
+            () => services.AddZbSecretsGrpcHub(Configuration()));
+
+        Assert.Contains("Secrets:GrpcHub:BearerToken", error.Message, StringComparison.Ordinal);
+    }
+
+    [Fact]
+    public void Registration_with_a_nonpositive_request_cap_throws()
+    {
+        var services = new ServiceCollection();
+
+        InvalidOperationException error = Assert.Throws<InvalidOperationException>(
+            () => services.AddZbSecretsGrpcHub(Configuration(
+                ("Secrets:GrpcHub:BearerToken", Token),
+                ("Secrets:GrpcHub:MaxNamesPerRequest", "0"))));
+
+        Assert.Contains("Secrets:GrpcHub:MaxNamesPerRequest", error.Message, StringComparison.Ordinal);
+    }
+
+    [Fact]
+    public void Registering_the_hub_twice_throws()
+    {
+        var services = new ServiceCollection();
+        IConfiguration configuration = Configuration(("Secrets:GrpcHub:BearerToken", Token));
+
+        services.AddZbSecretsGrpcHub(configuration);
+
+        InvalidOperationException error = Assert.Throws<InvalidOperationException>(
+            () => services.AddZbSecretsGrpcHub(configuration));
+
+        Assert.Contains("once", error.Message, StringComparison.OrdinalIgnoreCase);
+    }
+
+    [Fact]
+    public void Registering_the_hub_twice_under_different_sections_throws_rather_than_merging()
+    {
+        // This is the case the guard exists for: binding MERGES (the second section's absent
+        // BearerToken leaves the first one's standing) while the SectionPath stamp is last-one-wins,
+        // so the surviving options would report a section that did not supply the token they hold.
+        var services = new ServiceCollection();
+        IConfiguration configuration = Configuration(
+            ("Secrets:GrpcHub:BearerToken", Token),
+            ("Central:Secrets:Hub:MaxNamesPerRequest", "7"));
+
+        services.AddZbSecretsGrpcHub(configuration);
+
+        Assert.Throws<InvalidOperationException>(
+            () => services.AddZbSecretsGrpcHub(configuration, "Central:Secrets:Hub"));
+
+        SecretsGrpcHubServerOptions options = Resolve(services);
+        Assert.Equal("Secrets:GrpcHub", options.SectionPath);
+        Assert.Equal(Token, options.BearerToken);
+        Assert.Equal(1000, options.MaxNamesPerRequest);
+    }
+
+    private static IConfiguration Configuration(params (string Key, string Value)[] entries) =>
+        new ConfigurationBuilder()
+            .AddInMemoryCollection(entries.Select(e => new KeyValuePair<string, string?>(e.Key, e.Value)))
+            .Build();
+
+    private static SecretsGrpcHubServerOptions Resolve(IServiceCollection services)
+    {
+        using ServiceProvider provider = services.BuildServiceProvider();
+        return provider.GetRequiredService<IOptions<SecretsGrpcHubServerOptions>>().Value;
+    }
 }
@@ -155,7 +155,7 @@ public sealed class SecretsHubAuthInterceptorTests
    }

    [Fact]
-    public async Task Non_unary_calls_are_gated_too()
+    public async Task Server_streaming_calls_are_gated_too()
    {
        SecretsHubAuthInterceptor interceptor = Build(ConfiguredToken, out _);
        bool invoked = false;
@@ -175,6 +175,88 @@ public sealed class SecretsHubAuthInterceptorTests
        Assert.False(invoked);
    }

+    [Fact]
+    public async Task Client_streaming_calls_are_gated_too()
+    {
+        // The contract is unary-only today, so all four handler shapes are covered deliberately:
+        // an overload left ungated would be discovered by the first RPC that used it, in production.
+        SecretsHubAuthInterceptor interceptor = Build(ConfiguredToken, out _);
+        bool invoked = false;
+
+        RpcException error = await Assert.ThrowsAsync<RpcException>(
+            () => interceptor.ClientStreamingServerHandler(
+                new HubAsyncStreamReaderStub<GetSecretsRequest>(),
+                HubServerCallContextStub.WithAuthorization(header: null),
+                (_, _) =>
+                {
+                    invoked = true;
+                    return Task.FromResult(new GetSecretsResponse());
+                }));
+
+        Assert.Equal(StatusCode.Unauthenticated, error.StatusCode);
+        Assert.False(invoked);
+    }
+
+    [Fact]
+    public async Task Duplex_streaming_calls_are_gated_too()
+    {
+        SecretsHubAuthInterceptor interceptor = Build(ConfiguredToken, out _);
+        bool invoked = false;
+
+        RpcException error = await Assert.ThrowsAsync<RpcException>(
+            () => interceptor.DuplexStreamingServerHandler(
+                new HubAsyncStreamReaderStub<GetSecretsRequest>(),
+                new HubServerStreamWriterStub<GetSecretsResponse>(),
+                HubServerCallContextStub.WithAuthorization(header: null),
+                (_, _, _) =>
+                {
+                    invoked = true;
+                    return Task.CompletedTask;
+                }));
+
+        Assert.Equal(StatusCode.Unauthenticated, error.StatusCode);
+        Assert.False(invoked);
+    }
+
+    [Fact]
+    public async Task A_valid_token_reaches_every_streaming_continuation()
+    {
+        SecretsHubAuthInterceptor interceptor = Build(ConfiguredToken, out _);
+        string header = $"Bearer {ConfiguredToken}";
+        var reached = new List<string>();
+
+        await interceptor.ServerStreamingServerHandler(
+            new GetSecretsRequest(),
+            new HubServerStreamWriterStub<GetSecretsResponse>(),
+            HubServerCallContextStub.WithAuthorization(header),
+            (_, _, _) =>
+            {
+                reached.Add("server");
+                return Task.CompletedTask;
+            });
+
+        await interceptor.ClientStreamingServerHandler(
+            new HubAsyncStreamReaderStub<GetSecretsRequest>(),
+            HubServerCallContextStub.WithAuthorization(header),
+            (_, _) =>
+            {
+                reached.Add("client");
+                return Task.FromResult(new GetSecretsResponse());
+            });
+
+        await interceptor.DuplexStreamingServerHandler(
+            new HubAsyncStreamReaderStub<GetSecretsRequest>(),
+            new HubServerStreamWriterStub<GetSecretsResponse>(),
+            HubServerCallContextStub.WithAuthorization(header),
+            (_, _, _) =>
+            {
+                reached.Add("duplex");
+                return Task.CompletedTask;
+            });
+
+        Assert.Equal(["server", "client", "duplex"], reached);
+    }
+
    [Fact]
    public async Task No_log_line_ever_contains_token_material()
    {
@@ -238,11 +320,16 @@ public sealed class SecretsHubAuthInterceptorTests
 internal sealed class HubServerCallContextStub : ServerCallContext
 {
    private readonly Metadata _requestHeaders;
+    private readonly CancellationToken _cancellationToken;
    private readonly Metadata _responseTrailers = new();
    private readonly AuthContext _authContext = new(null, new Dictionary<string, List<AuthProperty>>());
    private readonly Dictionary<object, object> _userState = new();

-    private HubServerCallContextStub(Metadata requestHeaders) => _requestHeaders = requestHeaders;
+    private HubServerCallContextStub(Metadata requestHeaders, CancellationToken cancellationToken)
+    {
+        _requestHeaders = requestHeaders;
+        _cancellationToken = cancellationToken;
+    }

    /// <summary>Builds a context carrying the given <c>Authorization</c> header, or none when null.</summary>
    public static HubServerCallContextStub WithAuthorization(string? header)
@@ -253,18 +340,22 @@ internal sealed class HubServerCallContextStub : ServerCallContext
            headers.Add("Authorization", header);
        }

-        return new HubServerCallContextStub(headers);
+        return new HubServerCallContextStub(headers, CancellationToken.None);
    }

    /// <summary>Builds a context with no metadata at all, for service-level tests.</summary>
-    public static HubServerCallContextStub Empty() => new(new Metadata());
+    public static HubServerCallContextStub Empty() => new(new Metadata(), CancellationToken.None);
+
+    /// <summary>Builds a context whose call token is the given one, for propagation tests.</summary>
+    public static HubServerCallContextStub WithCancellation(CancellationToken cancellationToken) =>
+        new(new Metadata(), cancellationToken);

    protected override string MethodCore => "/zb.mom.ww.secrets.hub.v1.SecretsHub/Test";
    protected override string HostCore => "localhost";
    protected override string PeerCore => "ipv4:127.0.0.1:0";
    protected override DateTime DeadlineCore => DateTime.UtcNow.AddSeconds(30);
    protected override Metadata RequestHeadersCore => _requestHeaders;
-    protected override CancellationToken CancellationTokenCore => CancellationToken.None;
+    protected override CancellationToken CancellationTokenCore => _cancellationToken;
    protected override Metadata ResponseTrailersCore => _responseTrailers;
    protected override Status StatusCore { get; set; }
    protected override WriteOptions? WriteOptionsCore { get; set; }
@@ -294,6 +385,17 @@ internal sealed class HubServerStreamWriterStub<T> : IServerStreamWriter<T>
    }
 }

+/// <summary>An empty request stream, enough to drive the two client-reading interceptor paths.</summary>
+internal sealed class HubAsyncStreamReaderStub<T> : IAsyncStreamReader<T>
+    where T : class
+{
+    /// <inheritdoc/>
+    public T Current => throw new InvalidOperationException("The stub stream carries no messages.");
+
+    /// <inheritdoc/>
+    public Task<bool> MoveNext(CancellationToken cancellationToken) => Task.FromResult(false);
+}
+
 /// <summary>Captures formatted log messages so tests can assert on what was — and was not — logged.</summary>
 internal sealed class HubCapturingLogger<TCategory> : ILogger<TCategory>
 {
@@ -1,6 +1,8 @@
 using System.Globalization;
 using Google.Protobuf;
+using Grpc.Core;
 using Microsoft.Extensions.Logging.Abstractions;
+using Microsoft.Extensions.Options;
 using ZB.MOM.WW.Secrets.Abstractions;
 using ZB.MOM.WW.Secrets.Replicator.Grpc.V1;
 using ZB.MOM.WW.Secrets.Replicator.Grpc.Wire;
@@ -142,6 +144,106 @@ public sealed class SecretsHubServiceTests
        Assert.Equal(0, store.GetCallCount);
    }

+    [Fact]
+    public async Task GetSecrets_serves_a_request_exactly_at_the_cap()
+    {
+        var store = new HubFakeSecretStore();
+        store.Seed(Row("n1"));
+        store.Seed(Row("n2"));
+        store.Seed(Row("n3"));
+
+        var request = new GetSecretsRequest { Names = { "n1", "n2", "n3" } };
+
+        GetSecretsResponse response = await Service(store, maxNamesPerRequest: 3)
+            .GetSecrets(request, HubServerCallContextStub.Empty());
+
+        Assert.Equal(3, response.Secrets.Count);
+    }
+
+    [Fact]
+    public async Task GetSecrets_refuses_a_request_over_the_cap()
+    {
+        var store = new HubFakeSecretStore();
+        store.Seed(Row("n1"));
+
+        var request = new GetSecretsRequest { Names = { "n1", "n2", "n3", "n4" } };
+
+        RpcException error = await Assert.ThrowsAsync<RpcException>(
+            () => Service(store, maxNamesPerRequest: 3).GetSecrets(request, HubServerCallContextStub.Empty()));
+
+        Assert.Equal(StatusCode.ResourceExhausted, error.StatusCode);
+    }
+
+    [Fact]
+    public async Task GetSecrets_over_the_cap_reads_nothing_at_all()
+    {
+        // The refusal has to land BEFORE the sequential store loop — a cap that stops the response
+        // after doing the reads would defend nothing.
+        var store = new HubFakeSecretStore();
+        store.Seed(Row("n1"));
+
+        var request = new GetSecretsRequest { Names = { "n1", "n1", "n1" } };
+
+        await Assert.ThrowsAsync<RpcException>(
+            () => Service(store, maxNamesPerRequest: 2).GetSecrets(request, HubServerCallContextStub.Empty()));
+
+        Assert.Equal(0, store.GetCallCount);
+    }
+
+    [Fact]
+    public async Task GetSecrets_cap_refusal_states_the_cap_and_the_count_but_never_a_name()
+    {
+        var store = new HubFakeSecretStore();
+        var request = new GetSecretsRequest { Names = { "db/central", "db/site-a", "db/site-b" } };
+
+        RpcException error = await Assert.ThrowsAsync<RpcException>(
+            () => Service(store, maxNamesPerRequest: 2).GetSecrets(request, HubServerCallContextStub.Empty()));
+
+        Assert.Contains("2", error.Status.Detail, StringComparison.Ordinal);
+        Assert.Contains("3", error.Status.Detail, StringComparison.Ordinal);
+        foreach (string name in request.Names)
+        {
+            Assert.DoesNotContain(name, error.Status.Detail, StringComparison.OrdinalIgnoreCase);
+        }
+    }
+
+    [Fact]
+    public async Task GetSecrets_falls_back_to_the_default_cap_when_options_carry_a_nonpositive_one()
+    {
+        // Registration validates the cap, so this only happens when the options were built some
+        // other way — and the safe reading of "0" is the default, never "no cap".
+        var store = new HubFakeSecretStore();
+        var request = new GetSecretsRequest();
+        for (int i = 0; i <= SecretsGrpcHubServerOptions.DefaultMaxNamesPerRequest; i++)
+        {
+            request.Names.Add($"n{i}");
+        }
+
+        RpcException error = await Assert.ThrowsAsync<RpcException>(
+            () => Service(store, maxNamesPerRequest: 0).GetSecrets(request, HubServerCallContextStub.Empty()));
+
+        Assert.Equal(StatusCode.ResourceExhausted, error.StatusCode);
+    }
+
+    [Fact]
+    public async Task GetSecrets_hands_the_call_cancellation_token_to_the_store()
+    {
+        using var cts = new CancellationTokenSource();
+        await cts.CancelAsync();
+
+        var store = new HubFakeSecretStore();
+        store.Seed(Row("present"));
+
+        await Service(store).GetSecrets(
+            new GetSecretsRequest { Names = { "present" } },
+            HubServerCallContextStub.WithCancellation(cts.Token));
+
+        // The fake does not honour the token, so what is pinned here is the propagation itself: a
+        // real store sees the caller's cancellation, and an abandoned call stops costing reads.
+        Assert.True(store.LastCancellationToken.IsCancellationRequested);
+        Assert.Equal(cts.Token, store.LastCancellationToken);
+    }
+
    [Fact]
    public void DomainToWire_maps_a_fully_populated_row_field_by_field()
    {
@@ -231,8 +333,16 @@ public sealed class SecretsHubServiceTests
        Assert.Equal(expected, wire.ContentType);
    }

-    private static SecretsHubService Service(ISecretStore store) =>
-        new(store, NullLogger<SecretsHubService>.Instance);
+    private static SecretsHubService Service(ISecretStore store, int? maxNamesPerRequest = null)
+    {
+        var options = new SecretsGrpcHubServerOptions { BearerToken = "irrelevant-to-the-service" };
+        if (maxNamesPerRequest is int max)
+        {
+            options.MaxNamesPerRequest = max;
+        }
+
+        return new SecretsHubService(store, Options.Create(options), NullLogger<SecretsHubService>.Instance);
+    }

    private static StoredSecret Row(string name, bool isDeleted = false) => new()
    {
@@ -266,6 +376,9 @@ internal sealed class HubFakeSecretStore : ISecretStore
    /// <summary>How many single-row reads the service issued.</summary>
    public int GetCallCount { get; private set; }

+    /// <summary>The cancellation token the service passed on the most recent read.</summary>
+    public CancellationToken LastCancellationToken { get; private set; }
+
    /// <summary>Adds a row, and the manifest entry derived from it.</summary>
    public void Seed(StoredSecret row) => _rows[row.Name.Value] = row;

@@ -276,6 +389,7 @@ internal sealed class HubFakeSecretStore : ISecretStore
    public Task<StoredSecret?> GetAsync(SecretName name, CancellationToken ct)
    {
        GetCallCount++;
+        LastCancellationToken = ct;
        return Task.FromResult(_rows.GetValueOrDefault(name.Value));
    }