SerilogFactory don't log my messages but it logs exceptions - servicestack

Question

I want to use the SerilogFactory, the LogFactory is initialized before initializing the AppHost.
This is my startup.cs :
public class Startup
{
public Startup(IConfiguration configuration)
{
Configuration = configuration;
}
public IConfiguration Configuration { get; }
public void ConfigureServices(IServiceCollection services)
{
}
public void Configure(IApplicationBuilder app, IHostingEnvironment env)
{
if (env.IsDevelopment())
{
app.UseDeveloperExceptionPage();
}
var logger = new LoggerConfiguration().WriteTo.File("log.txt").CreateLogger();
LogManager.LogFactory = new SerilogFactory(logger);
app.Map("/api", api =>
{
api.UseServiceStack(new AppHost(env.ApplicationName, Configuration));
});
}
}
And this is my sample service :
public class TestService : ServiceStack.Service
{
public static ILog Log = LogManager.GetLogger(typeof(TestService));
public bool Get(GetTest request)
{
Log.Info("foo");
Log.Warn("???");
throw new System.Exception("plop");
return true;
}
}
After calling the "GetTest" request, I can see the details of the exception in my "log.txt" file but I can't see the Info "foo" or the Warm "???" in the file.
2019-07-03 18:07:55.597 +02:00 [INF] Initializing Application Tmpi.PocketTournee took 352.2006ms. No errors detected.
2019-07-03 18:08:07.446 +02:00 [ERR] ServiceBase<TRequest>::Service Exception
System.Exception: plop
at Tmpi.PocketTournee.ServiceInterface.TestService.Get(GetTest request) in C:\Projects\VS2017\PocketTournee\WebService\Sources\Tmpi.PocketTournee.ServiceInterface\TestService.cs:line 15
If I initialize the LogFactory AFTER initializing the AppHost, I can see my own logs but this time the exception details and the servicestack init info have disappeared :
2019-07-03 18:25:05.420 +02:00 [INF] foo
2019-07-03 18:25:05.434 +02:00 [WRN] ???

Answer 1

So I've set some breakpoint to watch the type of LogManager.LogFactory :
Before registering the first LogFactory the type of LogManager.LogFactory is ServiceStack.Logging.NullLogFactory
*After registering the first LogFactory the type of LogManager.LogFactory is of course ServiceStack.Logging.Serilog.SerilogFactory nothing wrong here
*But after AppHost initialization the type of LogManager.LogFactory is reverted to ServiceStack.NetCore.NetCoreLogFactory
Like in this code :
var logFactory = new SerilogFactory(new LoggerConfiguration()
.WriteTo.File("log.txt")
.CreateLogger());
// Here LogManager.LogFactory is {ServiceStack.Logging.NullLogFactory}
LogManager.LogFactory = logFactory;
// Here LogManager.LogFactory is {ServiceStack.Logging.Serilog.SerilogFactory}
app.Map("/api", api =>
{
api.UseServiceStack(new AppHost(env.ApplicationName, Configuration));
});
// Here LogManager.LogFactory is {ServiceStack.NetCore.NetCoreLogFactory}
LogManager.LogFactory = logFactory;