Issue #9: implement worker frame protocol

2026-04-26 16:20:16 -04:00
parent 41ddd122a6
commit a5098e6815
9 changed files with 511 additions and 0 deletions
@@ -0,0 +1,209 @@
+using System.Buffers.Binary;
+using Google.Protobuf;
+using MxGateway.Contracts;
+using MxGateway.Contracts.Proto;
+using MxGateway.Server.Workers;
+
+namespace MxGateway.Tests.Gateway.Workers;
+
+public sealed class WorkerFrameProtocolTests
+{
+    private const string SessionId = "session-1";
+
+    [Fact]
+    public async Task WriteAndReadAsync_WithValidEnvelope_RoundTripsFrame()
+    {
+        WorkerFrameProtocolOptions options = new(SessionId);
+        await using MemoryStream stream = new();
+        WorkerEnvelope original = CreateEnvelope();
+
+        WorkerFrameWriter writer = new(stream, options);
+        await writer.WriteAsync(original);
+        stream.Position = 0;
+
+        WorkerFrameReader reader = new(stream, options);
+        WorkerEnvelope parsed = await reader.ReadAsync();
+
+        Assert.Equal(original, parsed);
+    }
+
+    [Fact]
+    public async Task ReadAsync_WithPartialReads_ReassemblesFrame()
+    {
+        WorkerFrameProtocolOptions options = new(SessionId);
+        WorkerEnvelope original = CreateEnvelope();
+        byte[] frame = CreateFrame(original);
+        await using ChunkedReadStream stream = new(frame, chunkSize: 2);
+
+        WorkerFrameReader reader = new(stream, options);
+        WorkerEnvelope parsed = await reader.ReadAsync();
+
+        Assert.Equal(original, parsed);
+        Assert.True(stream.ReadCallCount > 2);
+    }
+
+    [Fact]
+    public async Task ReadAsync_WithZeroLengthFrame_ThrowsMalformedLength()
+    {
+        WorkerFrameProtocolOptions options = new(SessionId);
+        await using MemoryStream stream = new(new byte[sizeof(uint)]);
+
+        WorkerFrameReader reader = new(stream, options);
+        WorkerFrameProtocolException exception =
+            await Assert.ThrowsAsync<WorkerFrameProtocolException>(
+                async () => await reader.ReadAsync());
+
+        Assert.Equal(WorkerFrameProtocolErrorCode.MalformedLength, exception.ErrorCode);
+    }
+
+    [Fact]
+    public async Task ReadAsync_WithOversizedLength_ThrowsBeforePayloadAllocation()
+    {
+        WorkerFrameProtocolOptions options = new(SessionId, GatewayContractInfo.WorkerProtocolVersion, maxMessageBytes: 16);
+        byte[] lengthPrefix = new byte[sizeof(uint)];
+        BinaryPrimitives.WriteUInt32LittleEndian(lengthPrefix, 17);
+        await using MemoryStream stream = new(lengthPrefix);
+
+        WorkerFrameReader reader = new(stream, options);
+        WorkerFrameProtocolException exception =
+            await Assert.ThrowsAsync<WorkerFrameProtocolException>(
+                async () => await reader.ReadAsync());
+
+        Assert.Equal(WorkerFrameProtocolErrorCode.MessageTooLarge, exception.ErrorCode);
+    }
+
+    [Fact]
+    public async Task ReadAsync_WithWrongProtocolVersion_ThrowsProtocolVersionMismatch()
+    {
+        WorkerFrameProtocolOptions options = new(SessionId);
+        WorkerEnvelope envelope = CreateEnvelope();
+        envelope.ProtocolVersion++;
+        await using MemoryStream stream = new(CreateFrame(envelope));
+
+        WorkerFrameReader reader = new(stream, options);
+        WorkerFrameProtocolException exception =
+            await Assert.ThrowsAsync<WorkerFrameProtocolException>(
+                async () => await reader.ReadAsync());
+
+        Assert.Equal(WorkerFrameProtocolErrorCode.ProtocolVersionMismatch, exception.ErrorCode);
+    }
+
+    [Fact]
+    public async Task ReadAsync_WithWrongSessionId_ThrowsSessionMismatch()
+    {
+        WorkerFrameProtocolOptions options = new(SessionId);
+        WorkerEnvelope envelope = CreateEnvelope();
+        envelope.SessionId = "different-session";
+        await using MemoryStream stream = new(CreateFrame(envelope));
+
+        WorkerFrameReader reader = new(stream, options);
+        WorkerFrameProtocolException exception =
+            await Assert.ThrowsAsync<WorkerFrameProtocolException>(
+                async () => await reader.ReadAsync());
+
+        Assert.Equal(WorkerFrameProtocolErrorCode.SessionMismatch, exception.ErrorCode);
+    }
+
+    [Fact]
+    public async Task ReadAsync_WithMalformedPayload_ThrowsInvalidEnvelope()
+    {
+        WorkerFrameProtocolOptions options = new(SessionId);
+        byte[] frame = CreateFrame([0x80]);
+        await using MemoryStream stream = new(frame);
+
+        WorkerFrameReader reader = new(stream, options);
+        WorkerFrameProtocolException exception =
+            await Assert.ThrowsAsync<WorkerFrameProtocolException>(
+                async () => await reader.ReadAsync());
+
+        Assert.Equal(WorkerFrameProtocolErrorCode.InvalidEnvelope, exception.ErrorCode);
+    }
+
+    [Fact]
+    public async Task ReadAsync_WithMissingEnvelopeBody_ThrowsInvalidEnvelope()
+    {
+        WorkerFrameProtocolOptions options = new(SessionId);
+        WorkerEnvelope envelope = CreateEnvelope();
+        envelope.ClearBody();
+        await using MemoryStream stream = new(CreateFrame(envelope));
+
+        WorkerFrameReader reader = new(stream, options);
+        WorkerFrameProtocolException exception =
+            await Assert.ThrowsAsync<WorkerFrameProtocolException>(
+                async () => await reader.ReadAsync());
+
+        Assert.Equal(WorkerFrameProtocolErrorCode.InvalidEnvelope, exception.ErrorCode);
+    }
+
+    [Fact]
+    public async Task WriteAsync_WithOversizedEnvelope_ThrowsMessageTooLarge()
+    {
+        WorkerFrameProtocolOptions options = new(SessionId, GatewayContractInfo.WorkerProtocolVersion, maxMessageBytes: 8);
+        await using MemoryStream stream = new();
+
+        WorkerFrameWriter writer = new(stream, options);
+        WorkerFrameProtocolException exception =
+            await Assert.ThrowsAsync<WorkerFrameProtocolException>(
+                async () => await writer.WriteAsync(CreateEnvelope()));
+
+        Assert.Equal(WorkerFrameProtocolErrorCode.MessageTooLarge, exception.ErrorCode);
+        Assert.Equal(0, stream.Length);
+    }
+
+    private static WorkerEnvelope CreateEnvelope()
+    {
+        return new WorkerEnvelope
+        {
+            ProtocolVersion = GatewayContractInfo.WorkerProtocolVersion,
+            SessionId = SessionId,
+            Sequence = 1,
+            CorrelationId = "correlation-1",
+            WorkerHello = new WorkerHello
+            {
+                ProtocolVersion = GatewayContractInfo.WorkerProtocolVersion,
+                Nonce = "nonce",
+                WorkerProcessId = 1234,
+                WorkerVersion = "test-worker",
+            },
+        };
+    }
+
+    private static byte[] CreateFrame(IMessage message)
+    {
+        return CreateFrame(message.ToByteArray());
+    }
+
+    private static byte[] CreateFrame(byte[] payload)
+    {
+        byte[] frame = new byte[sizeof(uint) + payload.Length];
+        BinaryPrimitives.WriteUInt32LittleEndian(frame.AsSpan(0, sizeof(uint)), (uint)payload.Length);
+        payload.CopyTo(frame.AsSpan(sizeof(uint)));
+
+        return frame;
+    }
+
+    private sealed class ChunkedReadStream : MemoryStream
+    {
+        private readonly int _chunkSize;
+
+        public ChunkedReadStream(
+            byte[] buffer,
+            int chunkSize)
+            : base(buffer)
+        {
+            _chunkSize = chunkSize;
+        }
+
+        public int ReadCallCount { get; private set; }
+
+        public override ValueTask<int> ReadAsync(
+            Memory<byte> buffer,
+            CancellationToken cancellationToken = default)
+        {
+            ReadCallCount++;
+            int requestedCount = Math.Min(buffer.Length, _chunkSize);
+
+            return base.ReadAsync(buffer[..requestedCount], cancellationToken);
+        }
+    }
+}