Using Serilog with Elastic APM causes NullReferenceException

Describe the bug When using Serilog and Elastic APM together in Asp.Net COre, a NullReferenceException is thrown on start-up.

Versions: netcoreapp 2.1 Elastic.Apm.NetCoreAll 1.1.1 Serilog.AspnetCore 3.0.0

To Reproduce Steps to reproduce the behavior:

1. Clone this repo: https://github.com/scotmeiste/elastic-apm-serilog-error
2. in appsettings.json, replace ServerUrls and SecretToken with your instance of Elastic APM
3. Run Web Api project
4. See error in debug output (Debug Console tab in VS Code)

Elastic APM .NET Agent: [CRITICAL] Exception thrown by logging implementation. Log message: `The agent was started without a service name. The automatically discovered service name is {ServiceName}'. args.Length: 1. Current thread: managed ID: 1
Elastic APM .NET Agent: +-> Exception (exception): System.NullReferenceException: Object reference not set to an instance of an object.
Elastic APM .NET Agent:    at Serilog.Extensions.Logging.SerilogLogger.Log[TState](LogLevel logLevel, EventId eventId, TState state, Exception exception, Func`3 formatter)
   at Elastic.Apm.AspNetCore.AspNetCoreLogger.Log[TState](LogLevel level, TState state, Exception e, Func`3 formatter)
   at Elastic.Apm.Logging.LoggingExtensions.DoLog(IApmLogger logger, LogLevel level, String message, Exception e, Object[] args)e: <null>

Expected behavior Either no error, or a more helpful description of what went wrong.

[gregkalapos]

@scotm-gxg: The patch with the fix is out: https://github.com/elastic/apm-agent-dotnet/releases/tag/1.1.2 - so 1.1.2 should be ok with Serilog. The packages are also updated on nuget.org.

[gregkalapos]

Alright, looks like its working now!

Thanks for posting that fork/PR. it helped a ton. And thanks for the assistance!

Any idea when this will get rolled into a release? No rush or anything, just want to make sure I update the fix on my main project.

Awesome!

Regarding release: we already have 2 fairly important fixes on master. We don’t make promises on release dates, but I think having those 2 fixes out there would be important, so I’m thinking about a patch release very soon.