Clean up use of Python inference

src/AppHost/Python/PythonUvicornAppResourceBuilderExtensions.cs

@@ -1,16 +1,16 @@
-using AppHost;
-
-namespace Aspire.Hosting;
+namespace Aspire.Hosting;
 
 public static class PythonUvicornAppResourceBuilderExtensions
 {
     public static IResourceBuilder<PythonUvicornAppResource> AddPythonUvicornApp(this IDistributedApplicationBuilder builder, string name, string workingDirectory, int? port = default, int? targetPort = default)
     {
-        return builder.AddResource(new PythonUvicornAppResource(
-            name,
-            "python",
-            workingDirectory))
+        return builder.AddResource(new PythonUvicornAppResource(name, "python", workingDirectory))
             .WithArgs("-m", "uvicorn", "main:app")
             .WithHttpEndpoint(env: "UVICORN_PORT", port: port, targetPort: targetPort);
     }
 }
+
+public class PythonUvicornAppResource(string name, string command, string workingDirectory)
+    : ExecutableResource(name, command, workingDirectory), IResourceWithServiceDiscovery
+{
+}

src/Backend/Api/TicketApi.cs

@@ -149,9 +149,11 @@ private static async Task<IResult> CloseTicketAsync(AppDbContext dbContext, int
 
     private static async Task CreateTicketAsync(AppDbContext dbContext, TicketSummarizer summarizer, PythonInferenceClient pythonInference, CreateTicketRequest request)
     {
-        // Classify the new ticket
+        // Classify the new ticket using the small zero-shot classifier model
         var ticketTypes = Enum.GetValues<TicketType>();
-        var inferredTicketType = await pythonInference.ClassifyTextAsync(request.Message, ticketTypes.Select(type => type.ToString()));
+        var inferredTicketType = await pythonInference.ClassifyTextAsync(
+            request.Message,
+            candidateLabels: ticketTypes.Select(type => type.ToString()));
 
         var ticket = new Ticket
         {

src/ServiceDefaults/Clients/PythonInference/PythonInferenceClient.cs

@@ -4,9 +4,11 @@ namespace eShopSupport.ServiceDefaults.Clients.PythonInference;
 
 public class PythonInferenceClient(HttpClient http)
 {
-    public async Task<string> ClassifyTextAsync(string text, IEnumerable<string> candidateLabels)
+    public async Task<string?> ClassifyTextAsync(string text, IEnumerable<string> candidateLabels)
     {
-        var response = await http.PostAsJsonAsync("/classify", new { text = text, candidate_labels = candidateLabels });
-        return (await response.Content.ReadFromJsonAsync<string>())!;
+        var response = await http.PostAsJsonAsync("/classify",
+            new { text, candidate_labels = candidateLabels });
+        var label = await response.Content.ReadFromJsonAsync<string>();
+        return label;
     }
 }