Requests with the url http:/// causes the exception #278

SergeyKanzhelev · 2016-10-25T16:15:46Z

Reported by @stuartleeks: Trying to extract the host address from the url 'http:///' causes the exception.

stuartleeks · 2016-10-25T19:04:29Z

I have packaged an ASP.NET Core application in a Docker image and use the Application Insights .NET Core SDK. When I run the container under Marathon (on DCOS), the healthcheck URI sometimes shows in the logs as http:///. Unfortunately App Insights request pipeline throws an exception trying to retrieve the host name for these requests.

stuartleeks · 2016-10-25T19:07:04Z

I thought I'd saved the exception details, but can't find it. I'll recreate it if I get chance, but this is the line that was throwing IIRC: https://github.com/Microsoft/ApplicationInsights-aspnetcore/blob/bde2dcaf60ccbaf9b759597d9482ef4efa774fae/src/Microsoft.ApplicationInsights.AspNetCore/Extensions/HttpRequestExtensions.cs#L31

SergeyKanzhelev · 2016-10-25T20:11:54Z

Do you only get http:/// or also something like http:///items/10? I wonder how it is possible to get an empty host name.

stuartleeks · 2016-10-26T18:43:18Z

I set up the healthcheck in marathon to hit `/?healthcheck' (i.e. the root of the site with a healthcheck query string parameter to make the health checks easy to identify.

In the logs I see http://10.32.0.5:11800/?healthcheck and http:///?healthcheck, and the latter of these causes an exception:

fail: Microsoft.AspNetCore.Server.Kestrel[13]
      Connection id "0HKVTKBO51EQE": An unhandled exception was thrown by the application.
System.ArgumentException: Http request Host is not specified
   at Microsoft.ApplicationInsights.AspNetCore.Extensions.HttpRequestExtensions.GetUri(HttpRequest request)
   at Microsoft.ApplicationInsights.AspNetCore.RequestTrackingMiddleware.<Invoke>d__4.MoveNext()
--- End of stack trace from previous location where exception was thrown ---
   at System.Runtime.CompilerServices.TaskAwaiter.ThrowForNonSuccess(Task task)
   at System.Runtime.CompilerServices.TaskAwaiter.HandleNonSuccessAndDebuggerNotification(Task task)
   at Microsoft.AspNetCore.Hosting.Internal.RequestServicesContainerMiddleware.<Invoke>d__3.MoveNext()
--- End of stack trace from previous location where exception was thrown ---
   at System.Runtime.CompilerServices.TaskAwaiter.ThrowForNonSuccess(Task task)
   at System.Runtime.CompilerServices.TaskAwaiter.HandleNonSuccessAndDebuggerNotification(Task task)
   at Microsoft.AspNetCore.Server.Kestrel.Internal.Http.Frame`1.<RequestProcessingAsync>d__2.MoveNext()

If I disable Application Insights and redeploy then the app runs fine (i.e. ASP.NET Core is happy with the empty hostname):

info: Microsoft.AspNetCore.Hosting.Internal.WebHost[1]
      Request starting HTTP/1.0 GET http:///?healthcheck
info: Microsoft.AspNetCore.Mvc.Internal.ControllerActionInvoker[1]
      Executing action method Chess.Web.Controllers.GameController.Home (Chess.Web) with arguments () - ModelState is Valid
info: Microsoft.AspNetCore.Mvc.ViewFeatures.Internal.ViewResultExecutor[1]
      Executing ViewResult, running view at path /Views/Game/Home.cshtml.
info: Microsoft.AspNetCore.Mvc.Internal.ControllerActionInvoker[2]
      Executed action Chess.Web.Controllers.GameController.Home (Chess.Web) in 1.1041ms
...

SergeyKanzhelev · 2016-10-26T19:07:20Z

@Eilon, have you ever seen the empty hostname in URL? BTW, is there a way to get RawUrl from the request instead of constructing it like this: https://github.com/Microsoft/ApplicationInsights-aspnetcore/blob/master/src/Microsoft.ApplicationInsights.AspNetCore/Extensions/HttpRequestExtensions.cs#L17?

Eilon · 2016-10-26T19:10:35Z

@Tratcher would know best. This does seem very odd.

stuartleeks · 2016-10-26T19:27:17Z

With System.Uri, if I try new Uri("http:///") then I get

Unhandled Exception: System.UriFormatException: Invalid URI: The hostname could not be parsed.
   at System.Uri.CreateThis(String uri, Boolean dontEscape, UriKind uriKind)
   at System.Uri..ctor(String uriString)

Tratcher · 2016-10-26T19:51:51Z

Can you provide a full trace of the request? E.g. Fiddler/wireshark/etc.?

HTTP/1.0 did not require a Host header, that was a new requirement in HTTP/1.1. The client had a host in their original URL, but they did not transmit it to the server. Kestrel does not require a Host header on any version.

You can use GetEncodedUrl https://github.com/aspnet/HttpAbstractions/blob/dev/src/Microsoft.AspNetCore.Http.Extensions/UriHelper.cs#L166 to build the url correctly for most scenarios. Your version leaves out PathBase and incorrectly encodes Path https://github.com/Microsoft/ApplicationInsights-aspnetcore/blob/master/src/Microsoft.ApplicationInsights.AspNetCore/Extensions/HttpRequestExtensions.cs#L42. However GetEncodedUrl doesn't handle the missing Host scenario any better. When the Host is missing you must either provide a default or generate a relative uri (e.g. only the path and query).

The RawUrl is a misconception, there is no full raw url transmitted in an HTTP request, only pieces that must be assembled.

stuartleeks · 2016-10-26T20:05:55Z

I can't easily get the trace - I'm running this in Container Service under DCOS and Marathon. Marathon is executing the healthchecks, and the http:/// is coming from the default ASP.NET Core logging as per my earlier comment.

The only reason I tested parsing http:/// is because that is what the App Insights code here would do if the hostname check were relaxed: https://github.com/stuartleeks/ApplicationInsights-aspnetcore/blob/master/src/Microsoft.ApplicationInsights.AspNetCore/Extensions/HttpRequestExtensions.cs#L36

They're working with HttpRequest and seeing request.Host.HasValue as false.

In the absence of fiddler capture, is there any extra logging I can enable for ASP.NET Core that would help?

Tratcher · 2016-10-26T20:13:13Z

You can also enable Kestrel's connection level logging:
https://github.com/aspnet/KestrelHttpServer/blob/dev/samples/SampleApp/Startup.cs#L42

stuartleeks · 2016-10-27T11:56:29Z

Ok, I turned on the Kestrel logging and got the following output for the request without a hostname:

�[100m�[37mdbug�[39m�[0m:` LoggingConnectionFilter[0]
      ReadAsync[30] 47 45 54 20 2F 3F 68 65 61 6C 74 68 63 68 65 63 6B 20 48 54 54 50 2F 31 2E 30 0D 0A 0D 0A 
      GET /?healthcheck HTTP/1.0




�[100m�[32minfo�[39m�[0m: Microsoft.AspNetCore.Hosting.Internal.WebHost[1]
      Request starting HTTP/1.0 GET http:///?healthcheck

I do also see requests with the hostname:

�[100m�[37mdbug�[39m�[0m: LoggingConnectionFilter[0]
      ReadAsync[81] 47 45 54 20 2F 3F 68 65 61 6C 74 68 63 68 65 63 6B 20 48 54 54 50 2F 31 2E 31 0D 0A 48 6F 73 74 3A 20 31 30 2E 33 32 2E 30 2E 35 3A 31 35 31 30 0D 0A 55 73 65 72 2D 41 67 65 6E 74 3A 20 73 70 72 61 79 2D 63 61 6E 2F 31 2E 33 2E 33 0D 0A 0D 0A 
      GET /?healthcheck HTTP/1.1

      Host: 10.32.0.5:1510

      User-Agent: spray-can/1.3.3




�[100m�[32minfo�[39m�[0m: Microsoft.AspNetCore.Hosting.Internal.WebHost[1]
      Request starting HTTP/1.1 GET http://10.32.0.5:1510/?healthcheck

Tratcher · 2016-10-27T14:13:21Z

Ok, so it is a 1.0 request with no host header. @SergeyKanzhelev it looks like that method is only used here: https://github.com/Microsoft/ApplicationInsights-aspnetcore/blob/56dc5297134406d6b028076aa5b3582311412e74/src/Microsoft.ApplicationInsights.AspNetCore/RequestTrackingMiddleware.cs#L56 for logging purposes. In this case throwing is likely overkill, you should be able to provide defaults for any unknown values. e.g. "http://unspecified/path?query"

DamianEdwards · 2017-01-11T06:14:59Z

Looks like this still might be a problem in the new implementation in 2.0.0: https://github.com/Microsoft/ApplicationInsights-aspnetcore/blob/develop/src/Microsoft.ApplicationInsights.AspNetCore/DiagnosticListeners/Implementation/HostingDiagnosticListener.cs#L116

rh78 · 2017-03-14T10:05:58Z

Same problem here - I see it in the logs but do not know if there is any real problem coming out of it (will it throw to user level?)

stuartleeks · 2017-03-14T10:35:49Z

The issue I hit was that the healthcheck in DC/OS made the request, got a bad response and decided that the container instance was unhealthy and tore it down

rh78 · 2017-03-14T10:43:42Z

I see in Application Insights Log (running on Azure, ASP.NET Core on 4.6.2 FULL .Net Framework):
(it occurs every few minutes at random intervals):

System.ArgumentException:
   at Microsoft.ApplicationInsights.AspNetCore.Extensions.HttpRequestExtensions.GetUri (Microsoft.ApplicationInsights.AspNetCore, Version=2.0.0.0, Culture=neutral, PublicKeyToken=31bf3856ad364e35)
   at Microsoft.ApplicationInsights.AspNetCore.DiagnosticListeners.HostingDiagnosticListener.EndRequest (Microsoft.ApplicationInsights.AspNetCore, Version=2.0.0.0, Culture=neutral, PublicKeyToken=31bf3856ad364e35)
   at Proxy_Method_From_<>f__AnonymousType0`2_To_Void OnEndRequest(Microsoft.AspNetCore.Http.HttpContext, Int64) (Anonymously Hosted DynamicMethods Assembly, Version=0.0.0.0, Culture=neutral, PublicKeyToken=null)
   at Microsoft.Extensions.DiagnosticAdapter.DiagnosticSourceAdapter.Write (Microsoft.Extensions.DiagnosticAdapter, Version=1.1.0.0, Culture=neutral, PublicKeyToken=adb9793829ddae60)
   at Microsoft.Extensions.DiagnosticAdapter.DiagnosticSourceAdapter.System.IObserver<System.Collections.Generic.KeyValuePair<System.String,System.Object>>.OnNext (Microsoft.Extensions.DiagnosticAdapter, Version=1.1.0.0, Culture=neutral, PublicKeyToken=adb9793829ddae60)
   at System.Diagnostics.DiagnosticListener.Write (System.Diagnostics.DiagnosticSource, Version=4.0.1.0, Culture=neutral, PublicKeyToken=cc7b13ffcd2ddd51)
   at Microsoft.AspNetCore.Hosting.Internal.HostingApplication.DisposeContext (Microsoft.AspNetCore.Hosting, Version=1.1.0.0, Culture=neutral, PublicKeyToken=adb9793829ddae60)
   at Microsoft.AspNetCore.Server.WebListener.MessagePump+ApplicationWrapper`1.DisposeContext (Microsoft.AspNetCore.Server.WebListener, Version=1.1.0.0, Culture=neutral, PublicKeyToken=adb9793829ddae60)
   at Microsoft.AspNetCore.Server.WebListener.MessagePump+<ProcessRequestAsync>d__23.MoveNext (Microsoft.AspNetCore.Server.WebListener, Version=1.1.0.0, Culture=neutral, PublicKeyToken=adb9793829ddae60)
   at Microsoft.AspNetCore.Server.WebListener.MessagePump+<ProcessRequestAsync>d__23.MoveNext (Microsoft.AspNetCore.Server.WebListener, Version=1.1.0.0, Culture=neutral, PublicKeyToken=adb9793829ddae60)

trondhindenes · 2017-07-25T10:05:41Z

Any update on this? A lot of container schedulers seem to do healthchecks without sending in a host header.

glennc · 2018-01-23T01:53:58Z

If I read all this correctly then the following is true:

If there is no host header then the GetUri extension method will throw and fail the request
In HTTP 1.0 host is optional
Some health check systems, like DC/OS or HAProxy, send a 1.0 request by default with no host header.

There are two main workarounds:

Configure them to send the header. I know HAProxy can be configured for this, can the DC/OS system?
Put a proxy in front to normalize requests and handle requests with no header.

From an ASP.NET perspective, we could add a configuration option that lets you specify a string to use in place of the host when one isn't required. That would just add another option to the workarounds. But presumably we should be having GetUri not throw. So that leads to this question:

@SergeyKanzhelev presumably we need a valid URL for RequestTelemetry.URL. But is it used for more than just information to the user? App Insights could possibly leave it out or do something like use UNKNOWN_HOST if, for the known case of telemetry.Url, that is OK. But I don't know that it is.

SergeyKanzhelev · 2018-01-26T00:05:29Z

Application Insights does not do a lot of parsing of URL on backend. But it is enforces in C#. UNKNOWN_HOST will be good enough

stuartleeks · 2018-01-29T10:47:19Z

Looking at the code, AppInsights checks whether the host is set here, but that method returns a Uri instance. The result is consumed here and assigned to RequestTelemetry.Url which is a System.Uri and the Uri contstructor doesn't access UNKNOWN_HOST as a value. Any suggestions for an alternative to UNKNOWN_HOST?

Tratcher · 2018-01-29T15:03:23Z

UNKNOWN-HOST

cijothomas · 2018-05-08T19:05:31Z

Fixed with #677

SergeyKanzhelev added the bug label Oct 25, 2016

Dmitry-Matveev added this to the Dec-16 milestone Nov 18, 2016

Tratcher mentioned this issue Feb 14, 2018

Random spike in exceptions which look to maybe be coming from kestrel aspnet/KestrelHttpServer#2320

Closed

cijothomas modified the milestones: Dec-16, 2.3.0 May 8, 2018

cijothomas mentioned this issue May 8, 2018

Fix a bug which caused Requests to fail when HostName was empty. #677

Merged

5 tasks

cijothomas closed this as completed May 8, 2018

SergeyKanzhelev mentioned this issue Dec 18, 2018

Improved data collection for ASP.NET Core incoming requests census-instrumentation/opencensus-csharp#75

Merged

Tratcher mentioned this issue Dec 18, 2018

Provide a default Host header when it's missing/empty dotnet/aspnetcore#5909

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Requests with the url http:/// causes the exception #278

Requests with the url http:/// causes the exception #278

SergeyKanzhelev commented Oct 25, 2016

stuartleeks commented Oct 25, 2016

stuartleeks commented Oct 25, 2016 •

edited

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SergeyKanzhelev commented Oct 25, 2016

stuartleeks commented Oct 26, 2016 •

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SergeyKanzhelev commented Oct 26, 2016

Eilon commented Oct 26, 2016

stuartleeks commented Oct 26, 2016

Tratcher commented Oct 26, 2016

stuartleeks commented Oct 26, 2016

Tratcher commented Oct 26, 2016

stuartleeks commented Oct 27, 2016 •

edited

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Tratcher commented Oct 27, 2016

DamianEdwards commented Jan 11, 2017

rh78 commented Mar 14, 2017

stuartleeks commented Mar 14, 2017

rh78 commented Mar 14, 2017 •

edited by SergeyKanzhelev

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trondhindenes commented Jul 25, 2017

glennc commented Jan 23, 2018

SergeyKanzhelev commented Jan 26, 2018

stuartleeks commented Jan 29, 2018

Tratcher commented Jan 29, 2018

cijothomas commented May 8, 2018

Requests with the url http:/// causes the exception #278

Requests with the url http:/// causes the exception #278

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SergeyKanzhelev commented Oct 25, 2016

stuartleeks commented Oct 25, 2016

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rh78 commented Mar 14, 2017 •

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