PaTh.AzureFunctions.Tracing 1.1.0-beta

Azure Functions Tracing

Distributed tracing enhancements for Azure Functions using OpenTelemetry and Dynatrace. This package makes use of Castle Dynamic Proxy to intercept function invocations, adding distributed tracing via Dynatrace OpenTeleetry extension.

Read more about tracing Azure Functions

Features

The package provides a IFunctionHostBuilder extension to register all necessary components in your functions startup class.

It allows you to add tracing if you already use a startup class or want to customize the TraceProvider configuration.

By default the instrumentation adds automatic function tracing for any function trigger type and enables automatic distributed tracing for following triggers:

• HttpTrigger using a HttpRequest binding
• ServiceBusTrigger using a ServiceBusReceivedMessage binding

You can enable .NET Framworks additional instrumentation such as outgoing http or SQLclient calls.

Since October 2021, .NET Azure SDK comes with experimental OpenTelemetry support which gives additional trace details. While you can capture these spans span as described here, the Azure.Function.Tracing library adds selected and validated instrumentation filters via simple TraceProviderBuilder extension methods:

• AddServiceBusInstrumentation adds spans for Azure.Messaging.ServiceBus Client

ChangeLog

• v1.0.0 - Removed dependency on AutoFac. Removed parameter RegisterBuilder from configuration method AddFunctionTracing as it is no longer necessary to pass the services when using dependency injection in Azure Functions.
• v1.1.0 - Adding support for ServiceBus message tracing

Contribute

This is an open source project, and we gladly accept new contributions and contributors.

Enhancing the instrumentation to support other triggers

Enhacing the instrumentation is easy, as you only have to advance the interceptor logic in class FunctionInvocationInterceptor.

...
    public void Intercept(IInvocation invocation)
    {
        var attr = invocation.Method.GetCustomAttributes(typeof(FunctionNameAttribute), true);

        if (attr != null)
        {
            //check for incoming htttprequest
            var httpReq = invocation.Arguments.Where(a => a.GetType().IsSubclassOf(typeof(HttpRequest))).SingleOrDefault() as HttpRequest;
            ActivityContext parentContext = httpReq != null ? ExtractParentContext(httpReq) : default;

            AzureFunctionsCoreInstrumentation.TraceAsync(tracerProvider, ((FunctionNameAttribute)attr[0]).Name, () =>
            {
                invocation.Proceed();

                return Task.FromResult(invocation.ReturnValue);
            }, parentContext);
        }

    }

Support

This project is not an offical release of Dynatrace. If you have questions or any problems, open a github issue.

License

Licensed under Apache 2.0 license. See LICENSE for details.