Debug logs from NServiceBus and application code not showing up

[timbussmann]

The default log level for Azure Functions is set to Information. When lowering this level in the hosts.json to Debug, e.g.

{
    "version": "2.0",
    "logging": {
      "logLevel": {
        "default": "Debug"
      }
    }
}

debug log statements from NServiceBus, but also from user code that is using the logger retrieved via executionContext.GetLogger does not show up.

There is a corresponding issue in Microsoft's azure functions worker repo: Azure/azure-functions-dotnet-worker#573 (marked as duplicate of Azure/azure-functions-dotnet-worker#1125). This doesn't seem to be a NServiceBus related problem as this repro-sample doesn't use NSB at all.

---

The workaround to get the debug log statements working is to configure the logger on the host builder configuration in addition to the hosts.json:

var host = new HostBuilder()
    .ConfigureFunctionsWorkerDefaults()
    .ConfigureLogging(l =>
    {
        l.SetMinimumLevel(LogLevel.Debug);
    })
    ...