You can pass in a reference to :duct/logger

For example:

:app.handler/whatever
{:logger #ig/ref :duct/logger}

The :duct.module/logging module sets the configuration up with default logging configurations for both dev and prod.

In your handler itself, you'd access the logger like:

(defmethod ig/init-key :app.handler/whatever [_ {:keys [logger]}]
  (log/log logger :info ::message))

Newer versions of the duct/logger library also allow for (log/info logger ::message) as a shortcut.

I got it. Thanks.

If I want to use logger in ig/halt-key, then return {:server server :logger logger} is the way?

Yep

Thank you very much!

In Integrant 0.8.0-alpha2 I've added a resolve-key multimethod that might be useful if you just want to use the server in references.

Though it's still experimental functionality.

That sounds great.