Migrate app insights logging to open telemetry - Azure Functions don't show invocation

Question

After migrating to open telemetry for logging, Azure Functions don't log invocation anymore. The logs ARE showing up as tracings in app insights. It's just the invocations page is empty. It's a timer trigger.

my host.json

{
  "version": "2.0",
  "telemetryMode": "openTelemetry",
  "logging": {
    "fileLoggingMode": "debugOnly",
    "logLevel": {
      "default": "Warning",
      "Host.Aggregator": "Trace",
      "Host.Results": "Information",
      "Function": "Information"
    },
    "applicationInsights": {
      "LogLevel": {
        "Default": "Information"
      },
      "samplingSettings": {
        "isEnabled": false
      }
    }
  }
}

I'm basically using the defaults generated by Aspire with service defaults using builder.AddServiceDefaults()

Any help?

---

Full program.cs

var builder = FunctionsApplication.CreateBuilder(args);

builder.AddServiceDefaults();

builder.Services

    .AddDbContext<UserProfilesDbContext>(options => options.UseSqlServer(builder.Configuration.GetConnectionString("UserProfilesDbConnection")));

builder.Services.AddAzureClients(client =>

{

    var settings = builder.Configuration.GetSection("AzureOpenAI");

    client.AddSearchIndexClient(new Uri(settings["SearchEndpoint"]), new AzureKeyCredential(settings["SearchKey"]));

});

builder.Services.AddSingleton<AiSearchService>();

await builder.Build().RunAsync();

Answer 1

@Marcel Croes (DutchWorkz BV) ,

Thanks for reaching out.
When the host is configured to use OpenTelemetry, the Azure Portal currently doesn't support log streaming or recent function invocation traces via the "Function Invocations" page.

This is a known limitation documented by Microsoft:

https://learn.microsoft.com/en-us/azure/azure-functions/opentelemetry-howto?tabs=app-insights&pivots=programming-language-powershell#considerations-for-opentelemetry

As a result, while the traces are correctly collected and available in Application Insights (e.g., via the Logs (Analytics) tab), the standard invocation tracking UI will remain empty.

Hope this helps. Do let us know if you have any further queries.

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