[Hosting] Throw startup exceptions

[CodeBlanch]

Relates to #3753

Changes

• The IHostedService used by OpenTelemetry.Extensions.Hosting will now throw if it blows up starting TracerProvider or MeterProvider.

Details

• If you do this today using the "Sdk.Create" style you will get a NotSupportedException:

       using var provider = Sdk.CreateTracerProviderBuilder()
           .ConfigureBuilder((sp, sdkBuilder) =>
           {
               // Note: This throws because services cannot be
               // registered after IServiceProvider has been
               // created.
               sdkBuilder.SetSampler<MySampler>();
           })
           .Build();

• If you do this today using the hosting style an internal log is written but otherwise nothing happens:

           services.AddOpenTelemetry()
               .WithTracing(builder =>
               {
                   builder.ConfigureBuilder((sp, sdkBuilder) =>
                   {
                       // Note: This throws because services cannot be
                       // registered after IServiceProvider has been
                       // created.
                       sdkBuilder.SetSampler<MySampler>();
                   });
               })
               .StartWithHost();

The goal of the change is to make the behavior consistent and notify users when they have made a mistake.

The above example is a dev issue but other kinds of problems will also now blow up the process. Bad configuration, invalid permissions, port issues, etc. Discussing with @alanwest we felt it was better to surface these types of issues immediately and prevent the process from starting.

TODOs

• Appropriate CHANGELOG.md updated for non-trivial changes

[utpilla]

Have dedicated events for TracerProvider and MeterProvider instead of using the same?

[CodeBlanch]

Updated!

[codecov]

Codecov Report

Merging #4006 (6c1b075) into main (733a868) will increase coverage by 0.01%.
The diff coverage is 100.00%.

Additional details and impacted files

@@            Coverage Diff             @@
##             main    #4006      +/-   ##
==========================================
+ Coverage   85.46%   85.48%   +0.01%     
==========================================
  Files         289      289              
  Lines       11237    11229       -8     
==========================================
- Hits         9604     9599       -5     
+ Misses       1633     1630       -3     

Impacted Files	Coverage Δ
...ing/Implementation/HostingExtensionsEventSource.cs	100.00% <100.00%> (+54.54%)	⬆️
...s.Hosting/Implementation/TelemetryHostedService.cs	100.00% <100.00%> (+26.66%)	⬆️
...tation/OpenTelemetryProtocolExporterEventSource.cs	85.00% <0.00%> (-15.00%)	⬇️
...porter.OpenTelemetryProtocol/OtlpMetricExporter.cs	72.72% <0.00%> (-13.64%)	⬇️
...tpListener/Internal/PrometheusCollectionManager.cs	73.62% <0.00%> (-2.20%)	⬇️
src/OpenTelemetry/BatchExportProcessor.cs	82.24% <0.00%> (-1.87%)	⬇️
...Telemetry/Internal/SelfDiagnosticsEventListener.cs	97.65% <0.00%> (+0.78%)	⬆️
...lementation/SqlClientInstrumentationEventSource.cs	75.00% <0.00%> (+4.16%)	⬆️
...ZPages/Implementation/ZPagesExporterEventSource.cs	62.50% <0.00%> (+6.25%)	⬆️

[cijothomas]

nit: add a comment saying intentionally not catching ex, to let it bubble up.