Re: Logging in a Web App (Threads, Sessions and Requests)

Have you tried creating a HttpModule and populating the MDC that way?
There are lot of events you can subscribe to:

 http://www.eggheadcafe.com/articles/20030701.asp

One way to do it might be this way:

public class Log4NetHttpModule : System.Web.IHttpModule
{
 public Log4NetHttpModule()
 {

 }

 public void Init(System.Web.HttpApplication context)
 {
  context.AuthorizeRequest += new
EventHandler(context_AuthorizeRequest);
 }

 private void context_AuthorizeRequest(object sender, EventArgs e)
 {
  HttpApplication context = (HttpApplication)sender;

  if (context.Request.IsAuthenticated == true)
  {
   log4net.MDC.Set("UserIdentityName", context.User.Identity.Name);
  }
  else
  {
   log4net.MDC.Set("UserIdentityName", "N/A");
  }
 }
        
 public void Dispose()
 {
                        
 }

Make sure to add this to your web.config:

<httpModules>
 <add type="Foo.HttpModules.Log4NetHttpModule, Foo"
name="Log4NetHttpModule" />
</httpModules>

inside of <system.web>

Here is the conversion pattern:

"%5p %d{yyyy-MM-dd hh:mm:ss tt} (%c:%L) - [%X{UserIdentityName}] %m%n"

I think NLog supports things like
${aspnet-session:variable=MyVariableName} directly in its conversion
patterns so you wouldn't have to mess with the HttpModule. 

- Ron

--- "Hart, Leo" <Leo.Hart@xxxxxxx> wrote:

> I have a Log4Net problem/situation that I'm sure many of you have
> come
> across and have (hopefully) overcome.  I scoured the 'net for an
> answer
> but wasn't able to find exactly what I needed.
>  
> I'm starting to use Log4Net in my web application and I'm quite
> pleased
> with it overall.  I was a user of Log4J when I was programming J2EE
> apps, so obviously Log4Net is a comfortable fit.  
>  
> I've embedded log statements throughout the various tiers of my
> enterprise app and it's outputting useful information to my rolling
> log
> file just fine.  The problem is when the app leaves my development
> machine and moves to a production server with multiple users hitting
> it
> at once.  At that point it becomes very difficult to identify which
> log
> entries pertain to which users.  
>  
> So obviously I want to embed the session ID and/or the request ID in
> my
> log entry.  The first thing that came to mind was to simply log the
> session/request IDs in the Page_Load/Page_Unload event, but that
> doesn't
> work because the other log entries that occur in between Page_Load
> and
> Page_Unload won't have that info.  
>  
> The next thing that came to mind was MDC/NDC.  The problem with that
> is
> that MDC/NDC seems to be thread-based and since a given IIS server
> thread can support multiple sessions at once, the sessionID MDC can
> be
> overwritten.  I realized this fact once I coded the following in my
> global.asax:
>  
> 
>       Sub Session_Start(ByVal sender As Object, ByVal e As EventArgs)
>           ' Fires when the session is started
> 
>           log4net.MDC.Set("sessionID", Session.SessionID)
> 
>           m_log.Info("Session " & Session.SessionID & " is starting.")
>       End Sub
>       
>       
> 
>       Sub Session_End(ByVal sender As Object, ByVal e As EventArgs)
>           ' Fires when the session ends
> 
>           log4net.MDC.Remove("sessionID")
> 
>           m_log.Info("Session " & Session.SessionID & " has ended.")
>       End Sub
> 
>       
> 
> The last approach that came to mind was making the MDC.Set/Remove
> calls
> in my ASPX page in the Page_Load/Page_Unload events, but that might
> not
> work either given that, once again, multiple sessions are in each
> thread.  Things would get especially confusing if I turned on logging
> in
> not only my presentation tier, but my business tier, my data tier and
> any third party assemblies I'm utilizing.
>  
> So what do I do?  How do I solve this problem?  CAN I solve this
> problem?
>  
>  
> Thanks for your time...
> Leo Hart
>