feat: add atomic ephemeral state (#6)

Closes #6
2026-07-16 05:32:48 +02:00
parent 47382ddadc
commit 02ca502a76
7 changed files with 1754 additions and 2 deletions
@@ -0,0 +1,279 @@
+using System.Collections.Frozen;
+using System.Diagnostics;
+using System.Net;
+using FinalFactory.Rendezvous.Contracts;
+
+namespace FinalFactory.Rendezvous.Server.State;
+
+internal interface IWallClock
+{
+    DateTimeOffset UtcNow { get; }
+}
+
+internal interface IMonotonicClock
+{
+    TimeSpan Elapsed { get; }
+}
+
+internal sealed class SystemRendezvousClock : IWallClock, IMonotonicClock
+{
+    private readonly long _origin = Stopwatch.GetTimestamp();
+
+    public DateTimeOffset UtcNow => DateTimeOffset.UtcNow;
+
+    public TimeSpan Elapsed => Stopwatch.GetElapsedTime(_origin);
+}
+
+internal sealed record EphemeralStoreOptions
+{
+    public int MaxListings { get; init; } = 25_000;
+    public int MaxPresenceBindings { get; init; } = 25_000;
+    public int MaxJoinAttempts { get; init; } = 10_000;
+    public int MaxReplayEntries { get; init; } = 30_000;
+    public int MaxRevocations { get; init; } = 10_000;
+    public int MaxIdempotencyEntries { get; init; } = 35_000;
+    public TimeSpan LeaseLifetime { get; init; } = TimeSpan.FromSeconds(60);
+    public TimeSpan PresenceLifetime { get; init; } = TimeSpan.FromSeconds(20);
+    public TimeSpan JoinAttemptLifetime { get; init; } = TimeSpan.FromSeconds(30);
+    public TimeSpan ReplayLifetime { get; init; } = TimeSpan.FromSeconds(30);
+    public TimeSpan IdempotencyLifetime { get; init; } = TimeSpan.FromMinutes(2);
+    public TimeSpan GracefulDrainLifetime { get; init; } = TimeSpan.FromSeconds(30);
+
+    public void Validate()
+    {
+        RequirePositive(MaxListings, nameof(MaxListings));
+        RequirePositive(MaxPresenceBindings, nameof(MaxPresenceBindings));
+        RequirePositive(MaxJoinAttempts, nameof(MaxJoinAttempts));
+        RequirePositive(MaxReplayEntries, nameof(MaxReplayEntries));
+        RequirePositive(MaxRevocations, nameof(MaxRevocations));
+        RequirePositive(MaxIdempotencyEntries, nameof(MaxIdempotencyEntries));
+        RequireDuration(LeaseLifetime, TimeSpan.FromSeconds(60), nameof(LeaseLifetime));
+        RequireDuration(PresenceLifetime, TimeSpan.FromSeconds(20), nameof(PresenceLifetime));
+        RequireDuration(JoinAttemptLifetime, TimeSpan.FromSeconds(30), nameof(JoinAttemptLifetime));
+        RequireDuration(ReplayLifetime, TimeSpan.FromSeconds(30), nameof(ReplayLifetime));
+        RequireDuration(IdempotencyLifetime, TimeSpan.FromMinutes(10), nameof(IdempotencyLifetime));
+        RequireDuration(GracefulDrainLifetime, TimeSpan.FromSeconds(30), nameof(GracefulDrainLifetime));
+    }
+
+    private static void RequirePositive(int value, string name)
+    {
+        if (value <= 0)
+        {
+            throw new ArgumentOutOfRangeException(name, "Store capacity must be positive.");
+        }
+    }
+
+    private static void RequireDuration(TimeSpan value, TimeSpan maximum, string name)
+    {
+        if (value <= TimeSpan.Zero || value > maximum)
+        {
+            throw new ArgumentOutOfRangeException(name, $"Duration must be positive and no greater than {maximum}.");
+        }
+    }
+}
+
+internal readonly record struct TenantScope(GameId GameId, EnvironmentId EnvironmentId);
+
+internal readonly record struct SecretFingerprint
+{
+    public SecretFingerprint(string value)
+    {
+        if (string.IsNullOrWhiteSpace(value) || value.Length > 128)
+        {
+            throw new ArgumentException("Secret fingerprints must contain 1-128 characters.", nameof(value));
+        }
+
+        Value = value;
+    }
+
+    public string Value { get; }
+    public bool IsValid => !string.IsNullOrWhiteSpace(Value) && Value.Length <= 128;
+    public override string ToString() => "[REDACTED]";
+}
+
+internal readonly record struct ObservedEndpoint
+{
+    public ObservedEndpoint(AddressFamilyKind addressFamily, string address, int port)
+    {
+        if (!IPAddress.TryParse(address, out IPAddress? parsed)
+            || (addressFamily == AddressFamilyKind.Ipv4 && parsed.AddressFamily != System.Net.Sockets.AddressFamily.InterNetwork)
+            || (addressFamily == AddressFamilyKind.Ipv6 && parsed.AddressFamily != System.Net.Sockets.AddressFamily.InterNetworkV6))
+        {
+            throw new ArgumentException("The address must match the declared address family.", nameof(address));
+        }
+
+        if (port is < 1 or > 65_535)
+        {
+            throw new ArgumentOutOfRangeException(nameof(port));
+        }
+
+        AddressFamily = addressFamily;
+        Address = parsed.ToString();
+        Port = port;
+    }
+
+    public AddressFamilyKind AddressFamily { get; }
+    public string Address { get; }
+    public int Port { get; }
+    public bool IsValid => !string.IsNullOrEmpty(Address)
+        && Port is >= 1 and <= 65_535
+        && AddressFamily is AddressFamilyKind.Ipv4 or AddressFamilyKind.Ipv6;
+}
+
+internal sealed record ListingDefinition
+{
+    public required SessionListingId ListingId { get; init; }
+    public required LeaseId LeaseId { get; init; }
+    public required TenantScope Scope { get; init; }
+    public required string OwnerSubject { get; init; }
+    public required RegionId RegionId { get; init; }
+    public required uint ProtocolVersion { get; init; }
+    public required string BuildVersion { get; init; }
+    public required string DisplayName { get; init; }
+    public required ListingVisibility Visibility { get; init; }
+    public required PublisherTrustMode TrustMode { get; init; }
+    public required int CurrentPlayers { get; init; }
+    public required int MaximumPlayers { get; init; }
+    public required IReadOnlyDictionary<string, string> Metadata { get; init; }
+    public required SecretFingerprint LeaseFingerprint { get; init; }
+    public required MediationHandle HostPresenceHandle { get; init; }
+    public required SecretFingerprint HostPresenceFingerprint { get; init; }
+}
+
+internal sealed record StoredListing
+{
+    public required ListingDefinition Definition { get; init; }
+    public required DateTimeOffset LeaseExpiresAt { get; init; }
+    public required long Version { get; init; }
+    public required bool HasFreshPresence { get; init; }
+
+    public static ListingDefinition Freeze(ListingDefinition source) => source with
+    {
+        Metadata = source.Metadata.ToFrozenDictionary(StringComparer.Ordinal),
+    };
+}
+
+internal sealed record CreateListingCommand(
+    string IdempotencyKey,
+    string RequestFingerprint,
+    ListingDefinition Listing,
+    int OwnerListingLimit = int.MaxValue);
+
+internal sealed record RenewLeaseCommand(
+    SessionListingId ListingId,
+    LeaseId LeaseId,
+    SecretFingerprint LeaseFingerprint,
+    long ExpectedVersion);
+
+internal sealed record DeleteListingCommand(
+    SessionListingId ListingId,
+    LeaseId LeaseId,
+    SecretFingerprint LeaseFingerprint);
+
+internal sealed record BindHostPresenceCommand(
+    MediationHandle Handle,
+    SecretFingerprint CapabilityFingerprint,
+    ObservedEndpoint PublicEndpoint,
+    ObservedEndpoint? LocalEndpoint);
+
+internal sealed record VisibleListingQuery(
+    TenantScope Scope,
+    uint ProtocolVersion,
+    RegionId? RegionId,
+    int MaximumResults = ContractLimits.BrowserPageMaxItems);
+
+internal enum AttemptPeerRole
+{
+    Host = 1,
+    Client = 2,
+}
+
+internal sealed record CreateJoinAttemptCommand
+{
+    public required string IdempotencyOwner { get; init; }
+    public required string IdempotencyKey { get; init; }
+    public required string RequestFingerprint { get; init; }
+    public required string ClientSubject { get; init; }
+    public required JoinAttemptId AttemptId { get; init; }
+    public required MediationHandle MediationHandle { get; init; }
+    public required TenantScope Scope { get; init; }
+    public required SessionListingId ListingId { get; init; }
+    public required uint ProtocolVersion { get; init; }
+    public required SecretFingerprint HostCapabilityFingerprint { get; init; }
+    public required SecretFingerprint ClientCapabilityFingerprint { get; init; }
+    public int ScopeAttemptLimit { get; init; } = int.MaxValue;
+}
+
+internal sealed record AttemptEndpointBinding(
+    ObservedEndpoint PublicEndpoint,
+    ObservedEndpoint? LocalEndpoint);
+
+internal sealed record StoredJoinAttempt
+{
+    public required JoinAttemptId AttemptId { get; init; }
+    public required MediationHandle MediationHandle { get; init; }
+    public required TenantScope Scope { get; init; }
+    public required SessionListingId ListingId { get; init; }
+    public required string ClientSubject { get; init; }
+    public required uint ProtocolVersion { get; init; }
+    public required DateTimeOffset ExpiresAt { get; init; }
+    public AttemptEndpointBinding? HostEndpoint { get; init; }
+    public AttemptEndpointBinding? ClientEndpoint { get; init; }
+    public required bool IntroductionConsumed { get; init; }
+}
+
+internal sealed record BindAttemptEndpointCommand(
+    MediationHandle Handle,
+    AttemptPeerRole Role,
+    SecretFingerprint CapabilityFingerprint,
+    ObservedEndpoint PublicEndpoint,
+    ObservedEndpoint? LocalEndpoint);
+
+internal sealed record IntroductionEndpoints(
+    JoinAttemptId AttemptId,
+    AttemptEndpointBinding Host,
+    AttemptEndpointBinding Client);
+
+internal sealed record ReplayConsumption(
+    string Namespace,
+    string Key,
+    TimeSpan? Lifetime = null);
+
+internal enum StoreResultCode
+{
+    Success = 0,
+    NotFound = 1,
+    Expired = 2,
+    Revoked = 3,
+    Conflict = 4,
+    CapacityExceeded = 5,
+    Draining = 6,
+    ReplayRejected = 7,
+    ServiceUnavailable = 8,
+}
+
+internal sealed record StoreResult<T>(StoreResultCode Code, T? Value = default, bool IsIdempotentReplay = false)
+{
+    public bool Succeeded => Code == StoreResultCode.Success;
+}
+
+internal interface IEphemeralRendezvousStore
+{
+    Guid InstanceId { get; }
+    bool IsAvailable { get; }
+    bool IsDraining { get; }
+
+    StoreResult<StoredListing> CreateListing(CreateListingCommand command, CancellationToken cancellationToken = default);
+    StoreResult<StoredListing> RenewLease(RenewLeaseCommand command, CancellationToken cancellationToken = default);
+    StoreResult<bool> DeleteListing(DeleteListingCommand command, CancellationToken cancellationToken = default);
+    StoreResult<StoredListing> GetListing(SessionListingId listingId, bool requireFreshPresence, CancellationToken cancellationToken = default);
+    StoreResult<IReadOnlyList<StoredListing>> BrowseVisibleListings(VisibleListingQuery query, CancellationToken cancellationToken = default);
+    StoreResult<StoredListing> BindHostPresence(BindHostPresenceCommand command, CancellationToken cancellationToken = default);
+    StoreResult<StoredJoinAttempt> CreateJoinAttempt(CreateJoinAttemptCommand command, CancellationToken cancellationToken = default);
+    StoreResult<StoredJoinAttempt> BindAttemptEndpoint(BindAttemptEndpointCommand command, CancellationToken cancellationToken = default);
+    StoreResult<IntroductionEndpoints> ConsumeIntroduction(MediationHandle handle, CancellationToken cancellationToken = default);
+    StoreResult<bool> ConsumeReplay(ReplayConsumption consumption, CancellationToken cancellationToken = default);
+    StoreResult<bool> RevokeListing(SessionListingId listingId, CancellationToken cancellationToken = default);
+    StoreResult<int> RevokePrincipal(string subject, TimeSpan lifetime, CancellationToken cancellationToken = default);
+    void BeginDrain(CancellationToken cancellationToken = default);
+}