Feature Request: thread_id

[breezewish]

It would be great if the thread_id could be printed out, which could be helpful to learn the context in multi-threaded applications.

[Techcable]

I believe this should be possible through the use of the FnValue struct.

The following code should create a new child logger. The new child will have a "thread_id" key in its context, computed by the FnValue" Because the FnValue is lazily evaluated )only at the point logging actually occurs), you can even clone the child logger and use it from multiple threads.

let child = parent.new(o!(
    "thread_id" => slog::FnValue(|| {
        format!("{:?}", std::thread::current().id())
    })
));
// any use of the `child` logger will have `thread_id` as context.
play(&child);

You should also be able to modify this to work with the root loger (just move it to the initial o!() instead of creating a new child).

Please let me know if this doesn't work