.NET 8 ISOLATED upgrade stopped logging Infomation, Debug

Question

I recently upgraded our Azure Functions app from .NET 6 (in-progress model) to .NET 8 (isolated worker model). Some strange behavior is occuring where I'm unable to see Information (or below) level logs. The settings pertaining to logs are the same; everything worked in .NET 6. I'm trying to see these logs locally in my console.

Code:

Logger?.LogError("Test if we can log error");
Logger?.LogWarning("Test if we can log warning");
Logger?.LogInformation("Test if we can log info");
Logger?.LogDebug("Test if we can log debug");

Logs:

[2024-05-30T10:24:45.823Z] Test if we can log error
[2024-05-30T10:24:45.824Z] Test if we can log warning
.. that's it

Logging obviously works because I can see Error and Warning log levels. My host.json:

{
  "version": "2.0",
  "logging": {
    "logLevel": {
      "AlarmFunctions.Functions": "Debug",
      "DataLayer": "Debug",
      "ServiceLayer": "Debug",
      "Function": "Warning",
      "default": "Warning"
    },
    "applicationInsights": {
      "samplingSettings": {
        "isEnabled": true,
        "excludedTypes": "Trace;Request"
      },
      "LogLevel": {
        "Default": "Warning"
      }
    }
  }
}

Important to note is that logLevel in host.json does not apply anymore. Above provided logging code is located in namespace AlarmFunctions.Functions.SomeClassName but changing loglevel to "AlarmFunctions.Functions": "Error" still makes the warning log show up.

I tried changing ApplicationInsights log level as well but it doesn't change anything. I also tried this but it doesn't work either.

Am i missing something?

Thanks

Answer 1

If you are looking to set log levels specific to Functions. You need to add filter in Program.cs file.

My Function:

using Microsoft.AspNetCore.Http;
using Microsoft.Extensions.Logging;
using Microsoft.AspNetCore.Mvc;
using Microsoft.Azure.Functions.Worker;
using Microsoft.Azure.Functions.Worker.Http;
using System.Threading.Tasks;

namespace FunctionApp12
{
    public class Function1
    {
        private readonly ILogger<Function1> _logger;
        public Function1 (ILogger<Function1> logger)
        {
            _logger = logger;
        }
        [Function("Function1")]
        public IActionResult Run(
            [HttpTrigger(AuthorizationLevel.Function, "get", "post", Route = null)] HttpRequest req)
        {
            _logger?.LogCritical("Critical log");
            _logger?.LogWarning("Warning log");
            _logger?.LogError("Error Log");
            _logger?.LogInformation("Information log");

            var responseMessage = "Welcome to Azure Functions";

           return new OkObjectResult(responseMessage);
        }
    }
}

FunctionApp12.csproj:

<Project Sdk="Microsoft.NET.Sdk">
  <PropertyGroup>
    <TargetFramework>net8.0</TargetFramework>
    <AzureFunctionsVersion>v4</AzureFunctionsVersion>
    <OutputType>Exe</OutputType>
    <ImplicitUsings>enable</ImplicitUsings>
    <Nullable>enable</Nullable>
  </PropertyGroup>
  <ItemGroup>
    <FrameworkReference Include="Microsoft.AspNetCore.App" />
    <PackageReference Include="Microsoft.Azure.Functions.Worker.Extensions.Http" Version="3.2.0" />
    <PackageReference Include="Microsoft.Azure.Functions.Worker.Sdk" Version="1.17.2" />
    <PackageReference Include="Microsoft.Azure.Functions.Worker.Extensions.Http.AspNetCore" Version="1.3.1" />
    <PackageReference Include="Microsoft.ApplicationInsights.WorkerService" Version="2.22.0" />
    <PackageReference Include="Microsoft.Azure.Functions.Worker.ApplicationInsights" Version="1.2.0" />  
  </ItemGroup>
  <ItemGroup>
    <None Update="host.json">
      <CopyToOutputDirectory>PreserveNewest</CopyToOutputDirectory>
    </None>
    <None Update="local.settings.json">
      <CopyToOutputDirectory>PreserveNewest</CopyToOutputDirectory>
      <CopyToPublishDirectory>Never</CopyToPublishDirectory>
    </None>
  </ItemGroup>
</Project>

Program.cs:

using Microsoft.Extensions.DependencyInjection;
using Microsoft.Extensions.Configuration;
using Microsoft.Extensions.Hosting;
using Microsoft.Extensions.Logging;
using Microsoft.Azure.Functions.Worker;

var host = new HostBuilder()
    .ConfigureFunctionsWebApplication()
    .ConfigureServices(services =>
    {
        services.AddApplicationInsightsTelemetryWorkerService();
        services.ConfigureFunctionsApplicationInsights();
    })
    .ConfigureLogging((context, logging) =>
    {
       logging.AddFilter("FunctionApp12.Function1", LogLevel.Warning);
    })
    .Build();

host.Run();

host.json:

{
    "version": "2.0",
  "logging": {
    "logLevel": {
      "default": "Debug"
    },
    "applicationInsights": {
      "samplingSettings": {
        "isEnabled": true,
        "excludedTypes": "Request"
      },
      "enableLiveMetricsFilters": true
    }
  }
}

OUTPUT: