Pass logger dependency to PostSharp aspect

Question

I'm trying to pass my logger to a Logging Aspect that I've created with PostSharp. I have one logger per job run (because I need to send each job's logs to different folders), each job runs in different threads using BackgroundWorker. This is the code that I have:

[Serializable]
public class LogExecutionTimeAttribute : OnMethodBoundaryAspect
{
    [NonSerialized]
    public static Func<ILog> GetLogger;

    private string methodName;

    public override void CompileTimeInitialize(MethodBase method, AspectInfo aspectInfo)
    {
        this.methodName = method.Name;
    }

    public override void OnEntry(MethodExecutionArgs args)
    {
        args.MethodExecutionTag = Stopwatch.StartNew();
        base.OnEntry(args);
    }

    public override void OnExit(MethodExecutionArgs args)
    {
        Stopwatch sw = (Stopwatch)args.MethodExecutionTag;
        sw.Stop();
        var logger = GetLogger();
        logger.DebugFormat(
            "{0} executed in {1} seconds.", 
            this.methodName, 
            sw.ElapsedMilliseconds / 1000.0);
        base.OnExit(args);
    }
}

Each thread would do:

var log = CreateLoggerForJobId(jobId);
LogExecutionTimeAttribute.GetLogger = () => log;

I'm doubtful about the Func<ILog> GetLogger being static - How will it work when called from multiple threads? My manual tests seem to suggest that this is working, but I'm not sure if this is thread safe. I am also not sure if using NonSerialized attribute on GetLogger helps.

Entire working code is here:

https://gist.github.com/rnarayana/5518327f9c7c94f8c2fde4ae7fee7733

Answer 1

You're reading and writing the GetLogger static field on multiple threads simultaneously, so the shown code is not thread-safe. You can mark the field with the [ThreadStatic] attribute to have a unique value on each thread.

Also, you don't need to mark the field as [NonSerialized] because static fields are not serialized anyway (https://stackoverflow.com/questions/3903079/does-default-serialization-in-c-sharp-serialize-static-fields).