Logfile per Component Hierarchy

Question

Hello I have the following problem:

ComponentA with Unique Name
   ChildComponent
      ChildChild
   AnotherChild

Everytime a new instance of ComponentA is created I want to redirect the output to a unique file named ComponentA-UniqueName including all child component log entries.

How can this be achieved?

Daniel

Answer 1

Out of the box, dynamically changing appenders is hard to do. I would consider logging to a different medium, like a database table, that enables filtering and grouping log data.

Update:

Using contexts you can provide per-instance information across instance boundaries. Consider the following implementations:

class ComponentA
{
    public void DoStuff()
    {
        using(log4net.ThreadContext.Stacks["component"].Push(this.Id))
        {
            childComponent.DoStuff();
        }
    }
}

class ChildComponent
{
    public void DoStuff()
    {
        using(log4net.ThreadContext.Stacks["component"].Push(this.Id))
        {
            childChild.DoStuff();
        }
    }
}

Whenever messages are logged (regardless of which component does the logging), the current context stacks are included. In your appender configuration, use the %property{component} formatter to output the content of the component stack which will include ids of both the ComponentA instance and the ChildComponent instance.

Answer 2

I have a solution which works pretty fine for us:

http://gist.github.com/387423

Daniel