Improve OpenAI API error logging

src/Lib.Services/Services/OpenAiService/OpenAiService.cs

@@ -114,10 +114,19 @@ public OpenAiService(IOptions<OpenAiServiceOptions> options, IHttpClientFactory
         }
         catch (Exception ex)
         {
-            _logger.LogOpenAiApiServiceFailure(ex);
+            string errorResponseContent = await responseMessage.Content.ReadAsStringAsync();
+
+            OpenAiApiException openAiApiException = new(
+                message: $"An error occurred while interacting with the OpenAI API:\n{errorResponseContent}",
+                errorResponseContent: errorResponseContent,
+                httpStatusCode: responseMessage.StatusCode,
+                innerException: ex
+            );
+
+            _logger.LogOpenAiApiServiceFailure(openAiApiException);
             activity?.SetStatus(ActivityStatusCode.Error);
 
-            throw;
+            throw openAiApiException;
         }
 
         Stream responseStream = await responseMessage.Content.ReadAsStreamAsync();

src/Lib/Exceptions/OpenAi/OpenAiApiException.cs

@@ -0,0 +1,75 @@
+using System.Net;
+
+using MuzakBot.Lib.Models.OpenAi;
+
+namespace MuzakBot.Lib;
+
+/// <summary>
+/// Exception thrown when an error occurs while interacting with the OpenAI API.
+/// </summary>
+public class OpenAiApiException : Exception
+{
+    /// <summary>
+    /// Initializes a new instance of the <see cref="OpenAiApiException"/> class.
+    /// </summary>
+    /// <param name="message">The message that describes the error.</param>
+    /// <param name="errorResponseContent">The content of the error response from OpenAI.</param>
+    /// <param name="httpStatusCode">The HTTP status code of the response.</param>
+    public OpenAiApiException(string message, string errorResponseContent, HttpStatusCode httpStatusCode) : base(message)
+    {
+        ApiErrorResponse = JsonSerializer.Deserialize(
+            json: errorResponseContent,
+            jsonTypeInfo: OpenAiJsonContext.Default.OpenAiErrorResponse
+        );
+
+        HttpStatusCode = httpStatusCode;
+        HttpStatusCodeMessage = GetCommonHttpStatusCodeMessage(httpStatusCode);
+    }
+
+    /// <summary>
+    /// Initializes a new instance of the <see cref="OpenAiApiException"/> class.
+    /// </summary>
+    /// <param name="message">The message that describes the error.</param>
+    /// <param name="errorResponseContent">The content of the error response from OpenAI.</param>
+    /// <param name="httpStatusCode">The HTTP status code of the response.</param>
+    /// <param name="innerException">The exception that is the cause of the current exception.</param>
+    public OpenAiApiException(string message, string errorResponseContent, HttpStatusCode httpStatusCode, Exception innerException) : base(message, innerException)
+    {
+        ApiErrorResponse = JsonSerializer.Deserialize(
+            json: errorResponseContent,
+            jsonTypeInfo: OpenAiJsonContext.Default.OpenAiErrorResponse
+        );
+
+        HttpStatusCode = httpStatusCode;
+        HttpStatusCodeMessage = GetCommonHttpStatusCodeMessage(httpStatusCode);
+    }
+
+    /// <summary>
+    /// The error response from OpenAI.
+    /// </summary>
+    public OpenAiErrorResponse? ApiErrorResponse { get; set; }
+
+    /// <summary>
+    /// The HTTP status code of the response.
+    /// </summary>
+    public HttpStatusCode HttpStatusCode { get; set; }
+
+    /// <summary>
+    /// A message that describes the HTTP status code.
+    /// </summary>
+    public string HttpStatusCodeMessage { get; set; }
+
+    private static string GetCommonHttpStatusCodeMessage(HttpStatusCode httpStatusCode)
+    {
+        return httpStatusCode switch
+        {
+            HttpStatusCode.BadRequest => "Your request was malformed or missing some required parameters, such as a token or an input.",
+            HttpStatusCode.InternalServerError => "An error occurred on the OpenAI server. Please try again later.",
+            HttpStatusCode.NotFound => "The requested resource does not exist.",
+            HttpStatusCode.Unauthorized => "The provided API key does not have permission to access the requested resource.",
+            HttpStatusCode.TooManyRequests => "You have either exceeded the rate limit for the OpenAI API or you have run out of credits. Please try again later.",
+            HttpStatusCode.ServiceUnavailable => "OpenAI's API is experiencing high traffic. Please try again later.",
+            _ => "Unknown"
+        };
+    }
+}

src/Lib/JsonSourceGen/OpenAiJsonContext.cs

@@ -0,0 +1,18 @@
+using MuzakBot.Lib.Models.OpenAi;
+
+namespace MuzakBot.Lib;
+
+/// <summary>
+/// Source generation context for the OpenAI models.
+/// </summary>
+[JsonSourceGenerationOptions(
+    WriteIndented = false,
+    PropertyNamingPolicy = JsonKnownNamingPolicy.CamelCase,
+    GenerationMode = JsonSourceGenerationMode.Default,
+    DefaultIgnoreCondition = JsonIgnoreCondition.Never
+)]
+[JsonSerializable(typeof(OpenAiErrorResponse))]
+[JsonSerializable(typeof(OpenAiErrorData))]
+internal partial class OpenAiJsonContext : JsonSerializerContext
+{
+}

src/Lib/Models/OpenAi/OpenAiErrorData.cs

@@ -0,0 +1,31 @@
+namespace MuzakBot.Lib;
+
+/// <summary>
+/// Holds data for an error that occurred while interacting with the OpenAI API.
+/// </summary>
+public sealed class OpenAiErrorData
+{
+    /// <summary>
+    /// The error message.
+    /// </summary>
+    [JsonPropertyName("message")]
+    public string? Message { get; set; }
+
+    /// <summary>
+    /// The type of error that occurred.
+    /// </summary>
+    [JsonPropertyName("type")]
+    public string? ErrorType { get; set;}
+
+    /// <summary>
+    /// The parameter that caused the error.
+    /// </summary>
+    [JsonPropertyName("param")]
+    public string? Param { get; set; }
+
+    /// <summary>
+    /// The code of the error.
+    /// </summary>
+    [JsonPropertyName("code")]
+    public string? Code { get; set; }
+}

src/Lib/Models/OpenAi/OpenAiErrorResponse.cs

@@ -0,0 +1,13 @@
+namespace MuzakBot.Lib.Models.OpenAi;
+
+/// <summary>
+/// The response from the OpenAI API when an error occurs.
+/// </summary>
+public sealed class OpenAiErrorResponse
+{
+    /// <summary>
+    /// The error message.
+    /// </summary>
+    [JsonPropertyName("error")]
+    public OpenAiErrorData Error { get; set; } = null!;
+}