✅ 1. Azure Resources Checklist

Install These

brew install dotnet-sdk #This will be version 9 which will not work but gives you the rest of the stuff needed.
brew install azure-cli

Assuming you already have created a Resource Group named don-test-rg, an OpenAI deployment named and deployed a gpt model named gpt-4.1.

Install this from the webpage and follow directions. dotnet 8.x

Then these

dotnet add package Microsoft.Azure.Functions.Worker.Extensions.OpenApi --version 1.4.0
dotnet --list-sdks
dotnet add package Azure.AI.TextAnalytics --version 5.3.0
dotnet add package Azure.AI.OpenAI --version 2.0.0

Create Storage Account

az storage account create \
  --name dehamerfuncstorage \
  --location eastus \
  --resource-group don-test-rg \
  --sku Standard_LRS

Create Function Plan for Windows

az functionapp plan create \
  --resource-group don-test-rg \
  --name donfuncplan \
  --location eastus \
  --sku B1 \
  --is-linux false

Create Function App

az functionapp create \
  --resource-group don-test-rg \
  --name dehamerfuncapp \
  --plan donfuncplan \
  --storage-account dehamerfunctstorage \
  --runtime dotnet-isolated \
  --functions-version 4 \
  --os-type Windows

Create TexAnalytics

az cognitiveservices account create \
  --name dehamersentimentai \
  --resource-group don-test-rg \
  --location eastus \
  --kind TextAnalytics \
  --sku S \
  --custom-domain dehamersentimentai

az cognitiveservices account update \
  --name donsentimentai \
  --resource-group don-test-rg \
  --set properties.publicNetworkAccess=Enabled

Get keys and endpoint for export and app settings

export TEXT_ANALYTICS_ENDPOINT=`az cognitiveservices account show \ 
  --name dehamersentimentai \
  --resource-group don-test-rg \
  --query "properties.endpoint"|sed -e s:\"::g`

export TEXT_ANALYTICS_KEY=`az cognitiveservices account keys list \
  --name dehamersentimentai \
  --resource-group don-test-rg \
  --query "key1" -o tsv`

az functionapp config appsettings set \
  --name dehamerfuncapp \
  --resource-group don-test-rg \
  --settings \
  TEXT_ANALYTICS_ENDPOINT=$TEXT_ANALYTICS_ENDPOINT \
  TEXT_ANALYTICS_KEY=$TEXT_ANALYTICS_KEY
  
export OPENAI_KEY=`az cognitiveservices account keys list \
  --name don-openai-useast \
  --resource-group don-test-rg \
  --query "key1" -o tsv`

export OPENAI_ENDPOINT=https://don-openai-useast.openai.azure.com/

az functionapp config appsettings set \
  --name donfuncapp \
  --resource-group don-test-rg \
  --settings \
  OPENAI_KEY=$OPENAI_KEY \
  OPENAI_ENDPOINT=$OPENAI_ENDPOINT
  
#Confirm they were set
az functionapp config appsettings list \
  --name dehamerfuncapp \
  --resource-group don-test-rg \
  --query "[?starts_with(name, 'TEXT_') || starts_with(name, 'OPENAI_')]" -o table

Create a directory to store the functionapp files

mkdir ~/FeedbackFunctionDotNet
cd ~/FeedbackFunctionDotNet

Save the FeedbackFunction.cs, FeedbackFunction.csproj, global.json, host.json, and local.settings.json into the FeedBackFunctionDotNet directory.

FeedbackFunction.cs

using System.Net.Http.Headers;
using System.Text;
using System.Text.Json;
using Azure;
using Azure.AI.TextAnalytics;
using Microsoft.Azure.Functions.Worker;
using Microsoft.Azure.Functions.Worker.Http;
using Microsoft.Extensions.Logging;

public class DeHamerFeedbackFunction
{
    private readonly ILogger _logger;

    public DeHamerFeedbackFunction(ILoggerFactory loggerFactory)
    {
        _logger = loggerFactory.CreateLogger<DeHamerFeedbackFunction>();
    }

    [Function("DeHamerFeedbackFunction")]
    public async Task<HttpResponseData> Run(
        [HttpTrigger(AuthorizationLevel.Anonymous, "post", Route = null)]
        HttpRequestData req)
    {
        _logger.LogInformation("DeHamerFeedbackFunction triggered.");

        var requestBody = await new StreamReader(req.Body).ReadToEndAsync();
        var data = JsonSerializer.Deserialize<Dictionary<string, string>>(requestBody);
        string feedback = data?["feedback"] ?? string.Empty;

        // Get Text Analytics config
        var textEndpoint = Environment.GetEnvironmentVariable("TEXT_ANALYTICS_ENDPOINT");
        var textKey = Environment.GetEnvironmentVariable("TEXT_ANALYTICS_KEY");

        _logger.LogInformation("Using Text Analytics endpoint: {endpoint}", textEndpoint);

        var credentials = new AzureKeyCredential(textKey);
        var client = new TextAnalyticsClient(new Uri(textEndpoint), credentials);
        var documentSentiment = await client.AnalyzeSentimentAsync(feedback);
        var sentiment = documentSentiment.Value.Sentiment.ToString().ToLower();

        _logger.LogInformation("Sentiment detected: {sentiment}", sentiment);

        // Compose prompt
        string prompt = sentiment switch
        {
            "positive" => $"Respond in a cheerful and thankful tone to the following positive customer feedback:\n\"{feedback}\"",
            "negative" => $"Respond in a harsh, sarcastic, and annoyed tone to the following negative customer feedback:\n\"{feedback}\"",
            _ => $"Respond neutrally and professionally to the following feedback:\n\"{feedback}\""
        };

        // OpenAI Setup
        var openaiEndpoint = Environment.GetEnvironmentVariable("OPENAI_API_ENDPOINT")?.TrimEnd('/');
        var openaiKey = Environment.GetEnvironmentVariable("OPENAI_API_KEY");
        var deployment = Environment.GetEnvironmentVariable("OPENAI_DEPLOYMENT");

        _logger.LogInformation("Calling OpenAI at: {url}", $"{openaiEndpoint}/openai/deployments/{deployment}/chat/completions");

        using var httpClient = new HttpClient();
        httpClient.DefaultRequestHeaders.Authorization = new AuthenticationHeaderValue("Bearer", openaiKey);

        var payload = JsonSerializer.Serialize(new
        {
            messages = new[]
            {
                new { role = "system", content = "You are a customer support agent who mirrors the customer's sentiment tone." },
                new { role = "user", content = prompt }
            }
        });

        _logger.LogInformation("Payload sent to OpenAI: {payload}", payload);

        var response = await httpClient.PostAsync(
            $"{openaiEndpoint}/openai/deployments/{deployment}/chat/completions?api-version=2024-02-15-preview",
            new StringContent(payload, Encoding.UTF8, "application/json"));

        if (!response.IsSuccessStatusCode)
        {
            var errorDetails = await response.Content.ReadAsStringAsync();
            _logger.LogError("OpenAI API call failed: {status} - {details}", response.StatusCode, errorDetails);

            var errorResponse = req.CreateResponse(System.Net.HttpStatusCode.InternalServerError);
            await errorResponse.WriteAsJsonAsync(new { error = "Failed to get OpenAI response", status = response.StatusCode, details = errorDetails });
            return errorResponse;
        }

        var json = JsonDocument.Parse(await response.Content.ReadAsStringAsync());
        _logger.LogInformation("Raw OpenAI response: {json}", json);

        var message = json.RootElement.GetProperty("choices")[0].GetProperty("message").GetProperty("content").GetString();

        var result = new
        {
            sentiment = sentiment,
            message = message
        };

        var responseData = req.CreateResponse(System.Net.HttpStatusCode.OK);
        await responseData.WriteAsJsonAsync(result);
        return responseData;
    }
}

FeeedbackFunction.csproj

<Project Sdk="Microsoft.NET.Sdk.Worker">
  <PropertyGroup>
    <TargetFramework>net8.0</TargetFramework>
    <AzureFunctionsVersion>v4</AzureFunctionsVersion>
    <OutputType>Exe</OutputType>
    <Nullable>enable</Nullable>
    <ImplicitUsings>enable</ImplicitUsings>
  </PropertyGroup>

  <ItemGroup>
    <PackageReference Include="Azure.AI.TextAnalytics" Version="5.3.0" />
    <PackageReference Include="Microsoft.Azure.Functions.Worker" Version="1.17.0" />
    <PackageReference Include="Microsoft.Azure.Functions.Worker.Extensions.OpenApi" Version="1.5.0" />
    <PackageReference Include="Microsoft.Azure.Functions.Worker.Sdk" Version="1.17.0" OutputItemType="Analyzer" />
    <PackageReference Include="Microsoft.Azure.Functions.Worker.Extensions.Http" Version="3.1.0" />
    <PackageReference Include="Microsoft.Extensions.Logging.Console" Version="8.0.0" />
    <PackageReference Include="System.Text.Json" Version="8.0.0" />
  </ItemGroup>

  <ItemGroup>
    <None Update="host.json">
      <CopyToOutputDirectory>PreserveNewest</CopyToOutputDirectory>
    </None>
    <None Update="local.settings.json">
      <CopyToOutputDirectory>PreserveNewest</CopyToOutputDirectory>
      <CopyToPublishDirectory>Never</CopyToPublishDirectory>
    </None>
  </ItemGroup>

</Project>

Make sure this matches the version of dotnet 8.x you install.

global.json

{
  "sdk": {
    "version": "8.0.411"
  }
}

host.json

{
  "version": "2.0"
}

local.settings.json

{
  "IsEncrypted": false,
  "Values": {
    "AzureWebJobsStorage": "UseDevelopmentStorage=true",
    "FUNCTIONS_WORKER_RUNTIME": "dotnet-isolated"
  }
}