Serilog.Settings.Configuration is not working when it is referenced as package

Question

I am getting really strange behaviour trying to configure Serilog using appsettings.json.

It only works when I add Serilog.Settings.Configuration to my project using Add Project Reference. When Serilog.Settings.Configuration (3.2.0) is installed as package I am getting Exception:

System.InvalidOperationException: 'Cannot create instance of type 'Serilog.Formatting.ITextFormatter' because it is either abstract or an interface.'

Here is code example that I am using to parse configuration:

    var configuration = new ConfigurationBuilder()
        .SetBasePath(Directory.GetCurrentDirectory())
        .AddJsonFile("appsettings.json")
        .AddJsonFile($"appsettings.{Environment.GetEnvironmentVariable("ASPNETCORE_ENVIRONMENT") ?? "Production"}.json", true)
        .Build();

    var logger = new LoggerConfiguration()
        .ReadFrom.Configuration(configuration)
        .CreateLogger();

Here is config that I am using:

  "Serilog": {
    "MinimumLevel": {
      "Override": {
        "Microsoft": "Debug",
        "System": "Debug"
      }
    },
    "Enrich": [ "FromLogContext" ],
    "WriteTo": [
      {
        "Name": "Console",
        "Args": {
          "formatter": {
            "type": "Serilog.Templates.ExpressionTemplate, Serilog.Expressions",
            "template": "[{@t:yyyy-MM-dd HH:mm:ss.fff} {@l:u3}] {#if CorrelationId is not null}{CorrelationId} | {#end}{@m:lj}\n{@x}"
          }
        }
      }
    ]
  }

Here is an example of not working project file (Serilog.Settings.Configuration is PackageReference):

<Project Sdk="Microsoft.NET.Sdk.Web">

  <PropertyGroup>
    <TargetFramework>net5.0</TargetFramework>
    <UserSecretsId>0718b2b6-70cb-4a9b-9c43-30625d246f61</UserSecretsId>
    <DockerDefaultTargetOS>Linux</DockerDefaultTargetOS>
    <AssemblyName>SomeName</AssemblyName>
    <RootNamespace>SomeNamespace</RootNamespace>
    <Nullable>enable</Nullable>
  </PropertyGroup>

  <ItemGroup>
    <PackageReference Include="Microsoft.VisualStudio.Azure.Containers.Tools.Targets" Version="1.14.0" />
    <PackageReference Include="Serilog.AspNetCore" Version="4.1.0" />
    <PackageReference Include="Serilog.Expressions" Version="3.2.0" />
    <PackageReference Include="Serilog.Settings.Configuration" Version="3.2.0" />
  </ItemGroup>
    
</Project>

Here is an example of working project file (Serilog.Settings.Configuration is ProjectReference):

<Project Sdk="Microsoft.NET.Sdk.Web">

  <PropertyGroup>
    <TargetFramework>net5.0</TargetFramework>
    <UserSecretsId>0718b2b6-70cb-4a9b-9c43-30625d246f61</UserSecretsId>
    <DockerDefaultTargetOS>Linux</DockerDefaultTargetOS>
    <AssemblyName>SomeName</AssemblyName>
    <RootNamespace>SomeNamespace</RootNamespace>
    <Nullable>enable</Nullable>
  </PropertyGroup>

  <ItemGroup>
    <PackageReference Include="Microsoft.VisualStudio.Azure.Containers.Tools.Targets" Version="1.14.0" />
    <PackageReference Include="Serilog.AspNetCore" Version="4.1.0" />
    <PackageReference Include="Serilog.Expressions" Version="3.2.0" />
  </ItemGroup>

  <ItemGroup>
    <ProjectReference Include="..\..\..\serilog-settings-configuration-dev\src\Serilog.Settings.Configuration\Serilog.Settings.Configuration.csproj" />
  </ItemGroup>

</Project>

What am I missing? It looks like Serilog.Settings.Configuration is ignored when it is referenced as package, right? How can I fix that?

Answer 1

Update 2021-10-11: v3.3.0 has been released and includes the feature you're trying to use (Support of constructor parameters).

---

The feature you're trying to use (Support of constructor parameters) has not yet been released and as such is not present in the Serilog.Settings.Configuration 3.2.0 package which is why you get that error... This feature is planned to be released with 3.3.0 at date TBD.

You alternatives are:

1.) Use a pre-release package (e.g. 3.3.0-dev-00291)

<PackageReference Include="Serilog.Settings.Configuration" Version="3.3.0-dev-00291" />

2.) Compile it from source, as you demonstrated in your question

3.) Wait until 3.3.0 is out