Description
Component
OpenTelemetry.Instrumentation.Wcf
Package Version
| Package Name | Version |
|---|---|
| OpenTelemetry.Api | 1.8.0 |
| OpenTelemetry | 1.8.0 |
| TBD | TBD |
Runtime Version
net472
Description
Using the autogenerated "WCF Web HTTP Help Pages" (see more about those here) causes the WCF tracing instrumentation to throw an exception similar to the one below.
WebHost failed to process a request.
Sender Information: System.ServiceModel.Activation.HostedHttpRequestAsyncResult/16483014
Exception: System.ServiceModel.ServiceActivationException: The service '/MyService.svc' cannot be activated due to an exception during compilation. The exception message is: Value cannot be null.
Parameter name: key. ---> System.ArgumentNullException: Value cannot be null.
Parameter name: key
at System.ThrowHelper.ThrowArgumentNullException(ExceptionArgument argument)
at System.Collections.Generic.Dictionary`2.Insert(TKey key, TValue value, Boolean add)
at OpenTelemetry.Instrumentation.Wcf.TelemetryEndpointBehavior.ApplyDispatchBehaviorToEndpoint(EndpointDispatcher endpointDispatcher)
at System.ServiceModel.Description.DispatcherBuilder.InitializeServiceHost(ServiceDescription description, ServiceHostBase serviceHost)
at System.ServiceModel.ServiceHostBase.InitializeRuntime()
at System.ServiceModel.ServiceHostBase.OnOpen(TimeSpan timeout)
at System.ServiceModel.Channels.CommunicationObject.Open(TimeSpan timeout)
at System.ServiceModel.ServiceHostingEnvironment.HostingManager.ActivateService(ServiceActivationInfo serviceActivationInfo, EventTraceActivity eventTraceActivity)
at System.ServiceModel.ServiceHostingEnvironment.HostingManager.EnsureServiceAvailable(String normalizedVirtualPath, EventTraceActivity eventTraceActivity)
--- End of inner exception stack trace ---
at System.Runtime.AsyncResult.End[TAsyncResult](IAsyncResult result)
at System.ServiceModel.Activation.HostedHttpRequestAsyncResult.End(IAsyncResult result)
Process Name: w3wp
Process ID: 8416
The usage and autogeneration of these "WCF Web HTTP Help Pages" is controlled in the Web.config, and more specifically by <webHttp helpEnabled="true" ... >
These help pages are disabled by default, but if you have them, the autogenerated endpoint will lack the necessary "Action" and this will cause the instrumentation to blow up.
Screenshot below shows the workaround, which is disabling the help pages.
Screenshot below shows a sample help page:
Steps to Reproduce
- Add the automatic WCF instrumentation to the Tracer provider.
- Add the instrumentation to an endpoint behavior.
- Enable help pages for the same endpoint.
- Run the app and observe the exception when trying to hit the service endpoint.
Expected Result
Either the help pages should be excluded from instrumentation or they need to be handled properly.
Actual Result
An exception is thrown.
Exception: System.ServiceModel.ServiceActivationException: The service '/MyService.svc' cannot be activated due to an exception during compilation. The exception message is: Value cannot be null.
Additional Context
No response