Unable to initialize ConnectionConfiguration in certain conditions

[dsosunov]

NEST/Elasticsearch.Net 7.0+:

Elasticsearch any:

Indirect initialization of ConnectionConfiguration throws AmbiguousMatchException:
When an instance of ConnectionConfiguration is being initialized the static constructor is invoked indirectly by accessing to read-only static property to hold default user agent. By call stack it crash when accessing to RuntimeInformation.FrameworkDescription

[AmbiguousMatchException: Multiple custom attributes of the same type found.]
  System.Attribute.GetCustomAttribute(Assembly element, Type attributeType, Boolean inherit) +119
  Elasticsearch.Net.RuntimeInformation.get_FrameworkDescription() +96
  Elasticsearch.Net.ConnectionConfiguration..cctor() +402
[TypeInitializationException: The type initializer for 'Elasticsearch.Net.ConnectionConfiguration' threw an exception.]

We was able to localize the bug on RuntimeInformation

		public static string FrameworkDescription
		{
			get
			{
				if (_frameworkDescription == null)
				{
					var assemblyFileVersionAttribute =
						(AssemblyFileVersionAttribute)typeof(object).GetTypeInfo().Assembly.GetCustomAttribute(typeof(AssemblyFileVersionAttribute));
					_frameworkDescription = $".NET Framework {assemblyFileVersionAttribute.Version}";
				}
				return _frameworkDescription;
			}
		}

In unknown conditions depends on .NET Framework returns more than one attribute AssemblyFileVersionAttribute and Assembly.GetCustomAttribute throws an exception.

According to our investigation both attributes come from the same module but has different version of the file

System.Reflection.AssemblyFileVersionAttribute file:///C:/Windows/Microsoft.NET/Framework64/v4.0.30319/mscorlib.dll 4.0.30319
System.Reflection.AssemblyFileVersionAttribute file:///C:/Windows/Microsoft.NET/Framework64/v4.0.30319/mscorlib.dll 2.0.0.205

The first one always has .NET Framework version but the second one indicates version of something unknown for us 2.0.0.205

Issue was introduced in 7.x according to the sources
https://github.com/elastic/elasticsearch-net/blob/7.x/src/Elasticsearch.Net/Api/RuntimeInformation.cs

Steps to reproduce:

1. Initialize Elasticsearch client on web application

It can be reproduced only on some Windows Server and relevant only to web application.
On the same machine console application behaves as expected and .NET Framework objects has single attribute, that strange.

Our research was done on Windows Server 2012 & Windows Server 2012 R2 regardless of which build of .NET 4.7.2 is used.

We continue investigation to isolate it and find out which settings or conditions lead to have more than one attribute for system objects. It's not new issue with .NET

Add User-Agent string to API calls to Elasticsearch #3784:
With PR
#3784

As a suggested fix it's to read all attributes and filter them instead of attempt to read a single.

[Mpdreamz]

Thank you very much for reporting this, We will look to remedy this asap.

Out of interest do these two files also report AssemblyInformationalVersionAttribute twice?

This edge case could also bite our .NET apm agent if thats the case: https://github.com/elastic/apm-agent-dotnet/blob/2f5d7bf262e4e73d8d9c06dc110ca7367f801b62/src/Elastic.Apm/Helpers/PlatformDetection.cs#L64

cc @gregkalapos @SergeyKleyman

[dsosunov]

We didn't take a look on this attribute because we are not using any agents on impacted environment.
Our point of interests was only the attribute that leads to an exception.

[firatoltulu]

Hi @dsosunov ,
Can you solve this problem? i got this exception on Windows Server 2012 and IIS 8.5
anybody can help us?

[dsosunov]

No. I have no solution at all :(
And I have no idea what is the reason of this issue.

[firatoltulu]

I suggestion alternative a way, if you try run on IISExpress in same server its running correctly, that strange.

[dsosunov]

@firatoltulu It's true; Only in case if application hosts under IIS
The same code works fine as a console application and under IIS Express.

[SergeyKleyman]

You can use Max instead of sorting in descending order and then taking the first element.

[russcam]

You can use Max instead of sorting in descending order and then taking the first element.

That works too, and a little more succinct 🙂