Logging

The Virtual Parameter Service uses Serilog for structured logging and the standard ASP.NET Core logging framework for host-level messages.

Application Logging (Serilog)

Application logs capture the operational activity of the VPS — session lifecycle events, parameter processing, errors, and diagnostics.

Configuration

Serilog is configured via the Serilog section in AppConfig.json. See the AppConfig Reference for the full schema.

Log Levels

Level	When to Use
Verbose	Very detailed tracing information. Use only for deep debugging.
Debug	Internal system events useful for diagnosing problems.
Information	General operational events (session started, session ended).
Warning	Unexpected but recoverable situations.
Error	Failures that prevent part of the system from functioning.
Fatal	Critical failures that cause the service to stop.

Recommended production level

Use Information for production deployments. Switch to Debug when investigating issues.

Default Log File Location

When no log path is configured, logs are written to:

WindowsDocker

C:\ProgramData\Mclaren_Applied_Ltd\VirtualParameterService\Logs\vps-svc-log.txt

Specify explicitly via environment variable or command argument:

/logs/vps-svc-log.txt

Host Logging (ASP.NET Core)

The underlying .NET host produces its own log messages (startup diagnostics, hosting lifecycle events). These are configured separately via appsettings.json.

Reducing Host Log Noise

By default, appsettings.json is configured to minimise host log output:

{
  "Logging": {
    "LogLevel": {
      "Default": "Warning",
      "Microsoft.Hosting.Lifetime": "Warning",
      "Microsoft.AspNetCore.Hosting.Diagnostics": "None"
    }
  }
}

This prevents the host framework from flooding the console with startup and request-handling messages, keeping the output focused on VPS-specific logs.

Info

appsettings.json is located in the root directory alongside the executable. It is separate from AppConfig.json.