Issues with OpenTelemetry Integration in .NET 8 Azure Function App

Question

Issues with OpenTelemetry Integration in .NET 8 Azure Function App

santosh kumar patro 0

A .NET 8 Function App has been developed using the isolated worker model, following the guidelines in the Microsoft documentation: OpenTelemetry with Azure Functions.

After deploying the application in a DEV environment and performing validation, it was discovered that no requests are being logged for the Function App; only entries for itemType: trace, dependency, and exception are visible. Additionally, all trace, dependency, and exception logs lack the operation_Name column. In contrast, when comparing with an API, entries include itemType: request, trace, dependency, and exception, and the operation_Name column is present.

For further details, refer to this Stack Overflow post: OpenTelemetry Integration Issue.

Could assistance be provided to understand the reasons for the issues encountered with this setup?

Khadeer Ali 4,705 Reputation points Microsoft External Staff

2025-04-23T10:05:21.0866667+00:00

@santosh kumar patro ,

Is your Function App using an HTTP trigger, or a different type (like Timer or Queue)? This helps determine if request logs should be expected, as they are only generated for HTTP-triggered functions.

RithwikBojja 1,375 Microsoft External Staff

Hi @santosh kumar patro, with the below code in Program.cs I am able to log the requests too:


using Microsoft.Extensions.Hosting;

using Microsoft.Extensions.DependencyInjection;

using Microsoft.Extensions.Configuration;

using Microsoft.Extensions.Logging;

using OpenTelemetry.Resources;

using OpenTelemetry.Trace;

using OpenTelemetry.Metrics;

using Azure.Monitor.OpenTelemetry.Exporter;

using FunctionApp12;

var chohost = new HostBuilder()

    .ConfigureFunctionsWebApplication()

    .ConfigureAppConfiguration(config =>

    {

        config.AddJsonFile("appsettings.json", optional: true, reloadOnChange: true)

              .AddEnvironmentVariables();

    })

    .ConfigureServices((context, services) =>

    {

        var config = context.Configuration;

        var chcnfg = new RithServiceCldOps();

        config.Bind("TestRith", chcnfg);

        string riappnme = "TestRIthwik";

        services.AddOpenTelemetry()

            .ConfigureResource(resource => resource.AddService(riappnme))

            .WithTracing(b =>

            {

                b.AddSource("Microsoft.Azure.Functions.Worker") 

                 .AddHttpClientInstrumentation()

                 .AddAzureMonitorTraceExporter(o =>

                 {

                     o.ConnectionString = chcnfg.testconstring;

                 });

            })

            .WithMetrics(b =>

            {

                b.AddHttpClientInstrumentation()

                 .AddRuntimeInstrumentation()

                 .AddAzureMonitorMetricExporter(o =>

                 {

                     o.ConnectionString = chcnfg.testconstring;

                 });

            });

        services.AddLogging(loggingBuilder =>

        {

            loggingBuilder.ClearProviders();

            loggingBuilder.AddOpenTelemetry(rilgr =>

            {

                rilgr.IncludeFormattedMessage = true;

                rilgr.IncludeScopes = true;

                rilgr.ParseStateValues = true;

                rilgr.AddAzureMonitorLogExporter(o =>

                {

                    o.ConnectionString = chcnfg.testconstring;

                });

            });

        });

    })

    .Build();

chohost.Run();

namespace FunctionApp12

{

    public class RithServiceCldOps

    {

        public string testconstring { get; set; } = string.Empty;

    }

}

Output: enter image description here

Only requests contains Operation Name and others do not contain since they are generated from function itself. But request has it since the function is being called or Triggered.

I hope this is helpful! Do not hesitate to let me know if you have any other questions

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Khadeer Ali 4,705 Reputation points Microsoft External Staff

2025-04-23T10:05:21.0866667+00:00

@santosh kumar patro ,

Is your Function App using an HTTP trigger, or a different type (like Timer or Queue)? This helps determine if request logs should be expected, as they are only generated for HTTP-triggered functions.

Answer 1

Hi @santosh kumar patro ,

To get requests to also be logged and Operation name in requests, you can use below code which works:

Program.cs:


using Microsoft.Extensions.Hosting;

using Microsoft.Extensions.DependencyInjection;

using Microsoft.Extensions.Configuration;

using Microsoft.Extensions.Logging;

using OpenTelemetry.Resources;

using OpenTelemetry.Trace;

using OpenTelemetry.Metrics;

using Azure.Monitor.OpenTelemetry.Exporter;

using System.Diagnostics;

using Microsoft.Azure.Functions.Worker.Middleware;

using Microsoft.Azure.Functions.Worker;

var tester = new HostBuilder()

    .ConfigureFunctionsWebApplication(o =>

    {

        o.UseMiddleware<OperationNameMiddleware>(); 

    })

    .ConfigureAppConfiguration(config =>

    {

        config.AddJsonFile("appsettings.json", optional: true, reloadOnChange: true)

              .AddEnvironmentVariables();

    })

    .ConfigureServices((context, services) =>

    {

        var config = context.Configuration;

        var telemetryConfig = new RithServiceCldOps();

        config.Bind("TestRith", telemetryConfig);

        string globalServiceName = "RithwikApp";

        var resourceAttributes = new Dictionary<string, object> {

            { "service.name", "RithwikApp" },

            { "service.namespace", "FunctionAPP" },

            { "service.instance.id", "RIthInstance" }

        };

        services.Configure<LoggerFilterOptions>(rich =>

        {

            LoggerFilterRule brch = rich.Rules.FirstOrDefault(rule => rule.ProviderName == "Microsoft.Extensions.Logging.ApplicationInsights.ApplicationInsightsLoggerProvider");

            if (brch is not null)

            {

                rich.Rules.Remove(brch);

            }

        });

        var resourceBuilder = ResourceBuilder.CreateDefault().AddAttributes(resourceAttributes);

        var globalActivitySource = new ActivitySource("MyCompany.MyApp");

        services.AddSingleton(globalActivitySource);

        services.AddOpenTelemetry()

            .ConfigureResource(resource => resource.AddService(globalServiceName).AddAttributes(resourceAttributes))

            .WithTracing(b =>

            {

                b

                    .AddSource("Microsoft.Azure.Functions.Worker")

                    .AddSource("MyCompany.MyApp")

                    .AddHttpClientInstrumentation()

                    .AddAzureMonitorTraceExporter(o =>

                    {

                        o.ConnectionString = telemetryConfig.testconstring;

                    });

            })

            .WithMetrics(b =>

            {

                b

                    .AddHttpClientInstrumentation()

                    .AddRuntimeInstrumentation()

                    .AddAzureMonitorMetricExporter(o =>

                    {

                        o.ConnectionString = telemetryConfig.testconstring;

                    });

            });

        services.AddLogging(loggingBuilder =>

        {

            loggingBuilder.ClearProviders();

            loggingBuilder.AddOpenTelemetry(logs =>

            {

                logs.IncludeFormattedMessage = true;

                logs.IncludeScopes = true;

                logs.ParseStateValues = true;

                logs.AddAzureMonitorLogExporter(o =>

                {

                    o.ConnectionString = telemetryConfig.testconstring;

                });

                logs.SetResourceBuilder(resourceBuilder);  // Add resource builder to logging

            });

        });

    });

tester.Build().Run();

public class RithServiceCldOps

{

    public string testconstring { get; set; } = string.Empty;

}

public class OperationNameMiddleware : IFunctionsWorkerMiddleware

{

    private readonly ActivitySource _activitySource;

    public OperationNameMiddleware(ActivitySource activitySource)

    {

        _activitySource = activitySource;

    }

    public async Task Invoke(FunctionContext context, FunctionExecutionDelegate next)

    {

        var functionName = context.FunctionDefinition.Name;

        using var activity = _activitySource.StartActivity(

            $"FunctionApp:{functionName}",

            ActivityKind.Server,

            Activity.Current?.Context ?? default);

        if (activity != null)

        {

            activity.DisplayName = $"FunctionApp:{functionName}";

            activity.AddTag("function.name", functionName);  

            Console.WriteLine($"Activity Started: {activity.DisplayName}"); 

        }

        using (var traceActivity = _activitySource.StartActivity("ProcessingStepX", ActivityKind.Internal))

        {

            traceActivity?.AddTag("step", "X");

            traceActivity?.SetStatus(ActivityStatusCode.Ok);

        }

        await next(context);

        if (activity != null)

        {

            Console.WriteLine($"Activity Ended: {activity.DisplayName}");

        }

    }

}

Output:

enter image description here

But, we cannot send Operation Name to Traces table using Open Telemetry. But we can check the data in custom dimensions as below:

enter image description here

If you want Operation Name, then you need to use Classic one not the Open telemetry:


AddApplicationInsightsTelemetryWorkerService();

ConfigureFunctionsApplicationInsights();

If this answer was helpful, please click "Accept the answer" and mark Yes, as this can help other community members.

enter image description here

If you have any other questions or are still experiencing issues, feel free to ask in the "comments" section, and I'd be happy to help.

santosh kumar patro 0 Reputation points

2025-04-24T10:35:55.7766667+00:00

Thanks @Khadeer Ali and @RithwikBojja for your response. In my case it is DurableFunction with three ActivityFunctions which gets invoked from the DurableFunction. Looks like request logs should be generated for HTTP-triggered functions only. I can see other itemTypes: traces, dependency, exception related entries for every request that I trigger to execute the DurableFunction

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