Azure Isolated Function does not route logs to serilog

[waynebrantley]

nothing that the function framework outputs ends up in serilog. This could be exceptions from any host extension like sqlTrigger.

Any injection of ILogger does work as expected.

Reproduction: ``func init

That gives you a base function project. Change program.cs to:

Log.Logger = new LoggerConfiguration()
    .MinimumLevel.Debug()
    .Enrich.FromLogContext()
    .WriteTo.Seq("http://localhost:5341")
    .CreateLogger();
    
var host = new HostBuilder()
    .ConfigureFunctionsWebApplication()
    .ConfigureServices(services =>
    {
        services.AddApplicationInsightsTelemetryWorkerService();
        services.ConfigureFunctionsApplicationInsights();
        services.AddSerilog(Log.Logger);
    })
    .Build();

host.Run();

When you run it you will see lots of output on the console screen - and none of that ends up in seq (did not go through serilog).

Add a function to the project (and the Microsoft.Azure.Functions.Worker.Extensions.Sql package):

using Microsoft.Azure.Functions.Worker;
using Microsoft.Azure.Functions.Worker.Extensions.Sql;

namespace Company.FunctionApp1;

public static class SqlTrigger
{

    [Function("SomeTrigger")]
    public static void Run(
        [SqlTrigger("[dbo].[SomeTable]", "Main.ConnectionString")]
        FunctionContext context)
    {
    }
}

Run that and you will see lots more logs and errors about the connection string not being valid - again none of that is in seq.

There are logs in seq (going thru serilog) in the above example from Microsoft.AspNetCore.DataProtection and Microsoft.Hosting, etc - so that part of the serilog works - but anything from function app does not.

Not sure if this is an issue with logging not setup properly by AddSerilog or if this is an issue with https://github.com/Azure/azure-functions-host or https://github.com/Azure/azure-webjobs-sdk

Thoughts?