HuggingFace backend implementation

dotnet/src/SemanticKernel.Test/AI/HuggingFace/HuggingFaceBackendTests.cs

@@ -0,0 +1,118 @@
+// Copyright (c) Microsoft. All rights reserved.
+
+using System;
+using System.Collections.Generic;
+using System.IO;
+using System.Linq;
+using System.Net;
+using System.Net.Http;
+using System.Threading;
+using System.Threading.Tasks;
+using Microsoft.SemanticKernel.AI;
+using Microsoft.SemanticKernel.AI.HuggingFace.Services;
+using Moq;
+using Moq.Protected;
+using Xunit;
+
+namespace SemanticKernelTests.AI.HuggingFace;
+
+/// <summary>
+/// Unit tests for <see cref="HuggingFaceBackend"/> class.
+/// </summary>
+public class HuggingFaceBackendTests : IDisposable
+{
+    private const string BaseUri = "http://localhost:5000";
+    private const string Model = "gpt2";
+
+    private readonly HttpResponseMessage _response = new()
+    {
+        StatusCode = HttpStatusCode.OK,
+    };
+
+    /// <summary>
+    /// Verifies that <see cref="HuggingFaceBackend.CompleteAsync(string, CompleteRequestSettings)"/>
+    /// returns expected completed text without errors.
+    /// </summary>
+    [Fact]
+    public async Task ItReturnsCompletionCorrectlyAsync()
+    {
+        // Arrange
+        const string prompt = "This is test";
+        CompleteRequestSettings requestSettings = new();
+
+        using var backend = this.CreateBackend(this.GetTestResponse("completion_test_response.json"));
+
+        // Act
+        var completion = await backend.CompleteAsync(prompt, requestSettings);
+
+        // Assert
+        Assert.Equal("This is test completion response", completion);
+    }
+
+    /// <summary>
+    /// Verifies that <see cref="HuggingFaceBackend.GenerateEmbeddingsAsync(IList{string})"/>
+    /// returns expected list of generated embeddings without errors.
+    /// </summary>
+    [Fact]
+    public async Task ItReturnsEmbeddingsCorrectlyAsync()
+    {
+        // Arrange
+        const int expectedEmbeddingCount = 1;
+        const int expectedVectorCount = 8;
+        List<string> data = new() { "test_string_1", "test_string_2", "test_string_3" };
+
+        using var backend = this.CreateBackend(this.GetTestResponse("embeddings_test_response.json"));
+
+        // Act
+        var embeddings = await backend.GenerateEmbeddingsAsync(data);
+
+        // Assert
+        Assert.NotNull(embeddings);
+        Assert.Equal(expectedEmbeddingCount, embeddings.Count);
+        Assert.Equal(expectedVectorCount, embeddings.First().Count);
+    }
+
+    /// <summary>
+    /// Reads test response from file for mocking purposes.
+    /// </summary>
+    /// <param name="fileName">Name of the file with test response.</param>
+    private string GetTestResponse(string fileName)
+    {
+        return File.ReadAllText($"./AI/HuggingFace/TestData/{fileName}");
+    }
+
+    /// <summary>
+    /// Initializes <see cref="HuggingFaceBackend"/> with mocked <see cref="HttpClientHandler"/>.
+    /// </summary>
+    /// <param name="testResponse">Test response for <see cref="HttpClientHandler"/> to return.</param>
+    private HuggingFaceBackend CreateBackend(string testResponse)
+    {
+        var httpClientHandler = new Mock<HttpClientHandler>();
+
+        this._response.Content = new StringContent(testResponse);
+
+        httpClientHandler
+            .Protected()
+            .Setup<Task<HttpResponseMessage>>(
+                "SendAsync",
+                ItExpr.IsAny<HttpRequestMessage>(),
+                ItExpr.IsAny<CancellationToken>())
+            .ReturnsAsync(this._response);
+
+        return new HuggingFaceBackend(BaseUri, Model, httpClientHandler.Object);
+    }
+
+    public void Dispose()
+    {
+        this.Dispose(true);
+        GC.SuppressFinalize(this);
+    }
+
+    protected virtual void Dispose(bool disposing)
+    {
+        if (disposing)
+        {
+            this._response.Dispose();
+        }
+    }
+}

dotnet/src/SemanticKernel.Test/AI/HuggingFace/TestData/completion_test_response.json

@@ -0,0 +1,19 @@
+{
+  "choices": [
+    {
+      "finish_reason": "test",
+      "index": 0,
+      "logprobs": "",
+      "text": "This is test completion response"
+    }
+  ],
+  "created": "Tue, 21 Mar 2023 11:18:04 GMT",
+  "id": "",
+  "model": "gpt2",
+  "object": "text_completion",
+  "usage": {
+    "completion_tokens": 32,
+    "prompt_tokens": 3,
+    "total_tokens": 35
+  }
+}

dotnet/src/SemanticKernel.Test/AI/HuggingFace/TestData/embeddings_test_response.json

@@ -0,0 +1,23 @@
+{
+  "data": [
+    {
+      "embedding": [
+        -0.08541165292263031,
+        0.08639130741357803,
+        -0.12805694341659546,
+        -0.2877824902534485,
+        0.2114177942276001,
+        -0.29374566674232483,
+        -0.10496602207422256,
+        0.009402364492416382
+      ],
+      "index": 0,
+      "object": "embedding"
+    }
+  ],
+  "object": "list",
+  "usage": {
+    "prompt_tokens": 15,
+    "total_tokens": 15
+  }
+}

dotnet/src/SemanticKernel.Test/SemanticKernel.Test.csproj

@@ -26,4 +26,13 @@
     <ProjectReference Include="..\SemanticKernel\SemanticKernel.csproj" />
   </ItemGroup>
 
+  <ItemGroup>
+    <None Update="AI\HuggingFace\TestData\completion_test_response.json">
+      <CopyToOutputDirectory>Always</CopyToOutputDirectory>
+    </None>
+    <None Update="AI\HuggingFace\TestData\embeddings_test_response.json">
+      <CopyToOutputDirectory>Always</CopyToOutputDirectory>
+    </None>
+  </ItemGroup>
+
 </Project>

dotnet/src/SemanticKernel/AI/HuggingFace/HttpSchema/CompletionRequest.cs

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+// Copyright (c) Microsoft. All rights reserved.
+
+using System;
+using System.Text.Json.Serialization;
+
+namespace Microsoft.SemanticKernel.AI.HuggingFace.HttpSchema;
+
+/// <summary>
+/// HTTP schema to perform completion request.
+/// </summary>
+[Serializable]
+public sealed class CompletionRequest
+{
+    /// <summary>
+    /// Prompt to complete.
+    /// </summary>
+    [JsonPropertyName("prompt")]
+    public string Prompt { get; set; } = string.Empty;
+
+    /// <summary>
+    /// Model to use for completion.
+    /// </summary>
+    [JsonPropertyName("model")]
+    public string Model { get; set; } = string.Empty;
+}

dotnet/src/SemanticKernel/AI/HuggingFace/HttpSchema/CompletionResponse.cs

@@ -0,0 +1,30 @@
+// Copyright (c) Microsoft. All rights reserved.
+
+using System.Collections.Generic;
+using System.Text.Json.Serialization;
+
+namespace Microsoft.SemanticKernel.AI.HuggingFace.HttpSchema;
+
+/// <summary>
+/// HTTP Schema for completion response.
+/// </summary>
+public sealed class CompletionResponse
+{
+    /// <summary>
+    /// Model containing possible completion option.
+    /// </summary>
+    public sealed class Choice
+    {
+        /// <summary>
+        /// Completed text.
+        /// </summary>
+        [JsonPropertyName("text")]
+        public string? Text { get; set; }
+    }
+
+    /// <summary>
+    /// List of possible completions.
+    /// </summary>
+    [JsonPropertyName("choices")]
+    public IList<Choice>? Choices { get; set; }
+}

dotnet/src/SemanticKernel/AI/HuggingFace/HttpSchema/EmbeddingRequest.cs

@@ -0,0 +1,26 @@
+// Copyright (c) Microsoft. All rights reserved.
+
+using System;
+using System.Collections.Generic;
+using System.Text.Json.Serialization;
+
+namespace Microsoft.SemanticKernel.AI.HuggingFace.HttpSchema;
+
+/// <summary>
+/// HTTP schema to perform embedding request.
+/// </summary>
+[Serializable]
+public sealed class EmbeddingRequest
+{
+    /// <summary>
+    /// Data to embed.
+    /// </summary>
+    [JsonPropertyName("input")]
+    public IList<string> Input { get; set; } = new List<string>();
+
+    /// <summary>
+    /// Model to use for embedding generation.
+    /// </summary>
+    [JsonPropertyName("model")]
+    public string Model { get; set; } = string.Empty;
+}

dotnet/src/SemanticKernel/AI/HuggingFace/HttpSchema/EmbeddingResponse.cs

@@ -0,0 +1,27 @@
+// Copyright (c) Microsoft. All rights reserved.
+
+using System.Collections.Generic;
+using System.Text.Json.Serialization;
+
+namespace Microsoft.SemanticKernel.AI.HuggingFace.HttpSchema;
+
+/// <summary>
+/// HTTP Schema for embedding response.
+/// </summary>
+public sealed class EmbeddingResponse
+{
+    /// <summary>
+    /// Model containing embedding.
+    /// </summary>
+    public sealed class EmbeddingVector
+    {
+        [JsonPropertyName("embedding")]
+        public IList<float>? Embedding { get; set; }
+    }
+
+    /// <summary>
+    /// List of embeddings.
+    /// </summary>
+    [JsonPropertyName("data")]
+    public IList<EmbeddingVector>? Embeddings { get; set; }
+}