Added WithEnvironmentName enricher

[Nevets82]

Added support for 'EnvironmentName' property based on DOTNET_ENVIRONMENT or ASPNETCORE_ENVIRONMENT environment variable. Basically adds 'Production', 'Staging', 'Development', ... to the event logs.

[Numpsy]

should it be adding the property in the case where neither environment variable is set?

[Nevets82]

We should probably add the property with value 'Production, as this seems to be the default case in the AspNetCore documentation and HostBuilder.CreateHostingEnvironment method.

• https://github.com/dotnet/AspNetCore.Docs/blob/master/aspnetcore/fundamentals/environments.md
• https://github.com/aspnet/Hosting/blob/f9d145887773e0c650e66165e0c61886153bcc0b/src/Microsoft.Extensions.Hosting/HostBuilder.cs#L134

[nblumhardt]

This seems reasonable based one the current contents of this library 👍

I wonder though if, in the bigger picture, we're not adding a lot here now that can't be written more obviously as variations of:

.Enrich.WithProperty("EnvironmentName", Environment.GetEnvironmentVariable("DOTNET_ENVIRONMENT") ?? "Production")

I notice that in the ASP.NET Core docs, it mentions that ASPNETCORE_ENVIRONMENT overrides the DOTNET_ENVIRONMENT - perhaps we should follow the same logic here?

[Numpsy]

Think that's what #24 was getting at?

[Nevets82]

The reason why I would add this to this package, is because it then can also be configured by adding WithEnvironmentName to the Enrich property in the serilog-settings-configuration.

The difference I see with #24 is that this is more a framework environment variable and #24 is a good solution for custom environment variables.

Concerning the order of ASPNETCORE_ENVIRONMENT or DOTNET_ENVIRONMENT, I added DOTNET_ENVIRONMENT first because this seems to be the new standard (since verion 3.0) and ASPNETCORE_ENVIRONMENT is in my opinion the default for backwards compatibility. But this can deffinitely be changed.

[nblumhardt]

👍 thanks for the reply.

I think we should follow the precedence the framework uses, since it would be confusing for the log to report e.g. "Production" while the app, using the variables in reverse order, might be in "Development"

https://docs.microsoft.com/en-us/aspnet/core/fundamentals/environments?view=aspnetcore-5.0#environments is the doc:

The ASPNETCORE_ENVIRONMENT value overrides DOTNET_ENVIRONMENT.

Otherwise LGTM!

[Nevets82]

OK, I concur. I changed the precedence to ASPNETCORE_ENVIRONMENT.

[nblumhardt]

👍