appenders can't be removed using (merge-config! {:appenders {:appender-name nil}})

[andreasthoelke]

Using [com.taoensso/timbre "4.3.1"] in a fresh project, when I run

(-> (timbre/merge-config! {:appenders {:println nil}})
    :appenders
    :println)

I get:

{:enabled? true,
 :async? false,
 :min-level nil,
 :rate-limit nil,
 :output-fn :inherit,
 :fn #object[taoensso.timbre.appenders.core$println_appender$fn__24977 0x7e0d7a88 "taoensso.timbre.appenders.core$println_appender$fn__24977@7e0d7a88"]}

instead of nil, as I would expect.

Similarly appenders that I add with merge-config!

(timbre/merge-config! {:appenders {:spit (appenders/spit-appender {:fname "log.txt"})}})

can't be removed via merge-config!

(-> (timbre/merge-config! {:appenders {:spit nil}})
    :appenders
    :spit)

returns:

{:enabled? true,
 :async? false,
 :min-level nil,
 :rate-limit nil,
 :output-fn :inherit,
 :fn #object[taoensso.timbre.appenders.core$println_appender$fn__24977 0x7e0d7a88 "taoensso.timbre.appenders.core$println_appender$fn__24977@7e0d7a88"]}

With regards to disabling (vs. removing) an appender (which seemed to be the problem here [https://github.com//issues/161]), you can still do

(timbre/merge-config! {:appenders {:println {:enabled? false}}})

I.e.

(-> (timbre/merge-config! {:appenders {:println {:enabled? false}}})
    :appenders
    :println)

returns enabled? false:

{:enabled? false,
 :async? false,
 :min-level nil,
 :rate-limit nil,
 :output-fn :inherit,
 :fn #object[taoensso.timbre.appenders.core$println_appender$fn__24977 0x7e0d7a88 "taoensso.timbre.appenders.core$println_appender$fn__24977@7e0d7a88"]}

as expected.

[ptaoussanis]

Hey Andreas, thanks so much for the detailed report! Have pushed a fix that'll go out with the next Timbre release.

In the meantime, your suggestion to use (timbre/merge-config! {:appenders {:println {:enabled? false}}}) is good. Otherwise folks can just mod their Timbre config map manually using the standard Clojure API, so something like: (timbre/swap-config! assoc-in [:appenders :println] nil), etc.

Whatever's most convenient, there's no magic happening underneath; Timbre's config is just a standard map (at timbre/*config*). To get rid of an appender you just need to remove the appender key (or set it's :enabled? val to false).

Cheers :-)

[andreasthoelke]

Thank you Peter! Yep, the config approach seems simple and super flexible.

Good point in using

(timbre/swap-config! assoc-in [:appenders :println :enabled?] false)

over

(timbre/merge-config! {:appenders {:println {:enabled? false}}})

as the former makes the path to the config param more readable.
And of cause you can have a helper like

(def set-log-config-param! (partial timbre/swap-config! assoc-in))

and then be even more consise and also compatible with the timbre v3.4.0 set-config! syntax:

(set-log-config-param! [:appenders :println :enabled?] false)

I wonder if a similar timbre/set-config-param! would make sense to ease transitioning
log configs between v3 and v4?

[ptaoussanis]

Hi Andreas, no problem :-)

I wonder if a similar timbre/set-config-param! would make sense to ease transitioning
log configs between v3 and v4?

Do you think this is a common problem? Is it because new users don't know how to use assoc-in? (Sincere question).

[andreasthoelke]

Yeah, I think (timbre/swap-config! assoc-in [:appenders :println :enabled?] false) will do fine. It makes it clear what is happening under the hood.
Thanks again for the considered response!