How can I log benchmark tests to CSV file in MVC controllers? - asp.net-mvc

Question

I have an ASP.NET Core app with various controllers that inherit from BaseController. I need to implement some basic benchmarking tests, using Stopwatch, it will just start at the beginning of an action method and finish at the end. I can turn this on and off via appsettings.json. There is an ILogger factory in Startup.cs:
public void Configure ( IApplicationBuilder app, IHostingEnvironment env, ILoggerFactory loggerFactory ) {
loggerFactory.AddConsole( Configuration.GetSection( "Logging" ) );
loggerFactory.AddDebug();
loggerFactory.AddFile(#"C:\Logs\Portal\portal-{Date}.txt");
I have added ILogger to my BaseController (below), I am hoping this will be supplied via DI. Given the above, can I use this to log my benchmark results to file in a different location to the startup file? I would like a .csv file with certain columns which i can populate with results. Is this possible?
public class BaseController : Controller {
protected AppSettings AppSettings;
protected IMapper Mapper;
protected IPortalApiService PortalApiService;
protected ILogger Logger;
protected UserManager<ApplicationUser> UserManager;
private static Stopwatch _stopWatch = new Stopwatch();
private static long _seconds;
public BaseController ( IMapper mapper,
IOptions<AppSettings> appSettings,
UserManager<ApplicationUser> userManager,
IPortalApiService PortalApiService,
ILogger logger) {
Mapper = mapper;
AppSettings = appSettings.Value;
UserManager = userManager;
PortalApiService = PortalApiService;
Logger = logger;
}
public BaseController ( IMapper mapper,
IOptions<AppSettings> appSettings,
UserManager<ApplicationUser> userManager,
ILogger logger) {
Mapper = mapper;
AppSettings = appSettings.Value;
UserManager = userManager;
Logger = logger;
}
protected Task<ApplicationUser> GetCurrentUserAsync () {
return UserManager.GetUserAsync( HttpContext.User );
}
public void StartBenchmark()
{
if (AppSettings.EnableBenchmarkLogging)
{
_stopWatch = Stopwatch.StartNew();
}
}
public void EndBenchmark()
{
if (_stopWatch.IsRunning)
{
_stopWatch.Stop();
_seconds = _stopWatch.ElapsedMilliseconds;
//logging to do
}
}
}

Answer 1

It is not a good idea to use a BaseController in MVC. There are better ways to implement crosscutting concerns. In this particular case, you could use a global filter.
public class BenchmarkFilter : IActionFilter
{
private readonly ILogger Logger;
// DON'T DECLARE STATIC!!
private Stopwatch _stopWatch = new Stopwatch();
public BenchmarkFilter(ILogger logger)
{
_logger = logger ??
throw new ArgumentNullException(nameof(logger));
}
public void OnActionExecuting(ActionExecutingContext context)
{
_stopWatch = Stopwatch.StartNew();
}
public void OnActionExecuted(ActionExecutedContext context)
{
if (_stopWatch.IsRunning)
{
_stopWatch.Stop();
var seconds = _stopWatch.ElapsedMilliseconds;
//logging to do
}
}
}
This allows you to inject services via DI through the constructor without having to add those parameters to every controller that subclasses a common BaseController, separating the concern of benchmarking from the controller entirely.
Usage
In Startup.cs, add the filter in the ConfigureServices method.
public void ConfigureServices(IServiceCollection services)
{
services.AddMvc(options =>
{
options.Filters.Add(typeof(BenchmarkFilter)); // runs on every action method call
});
services.AddScoped<BenchmarkFilter>();
// ....
}