Experimental, subject to change.
Minimal Telemere facade API for library authors, etc.
Allows library code to use Telemere if it's present, or fall back to
something like `tools.logging` otherwise.

(ns my-lib
  (:require
    [taoensso.telemere.api :as t]   ; `com.taoensso/telemere-api` dependency
    [clojure.tools.logging :as ctl] ; `org.clojure/tools.logging` dependency
    ))

(t/require-telemere-if-present) ; Just below `ns` form

;; Optional convenience for library users
(defn set-min-level!
  "If using Telemere, sets Telemere's minimum level for <library> namespaces.
  Possible levels: #{:trace :debug :info :warn :error :fatal :report}.
  Default level: `:warn`.
  [min-level]
  (t/if-telemere
    (do (t/set-min-level! nil "my-lib(.*)" min-level) true)
    false))

(defonce ^:private __set-default-min-level (set-min-level! :warn))

(signal!
  {:kind :log, :id :my-id, :level :warn,
   :let  [x :x]
   :msg  ["Hello" "world" x]
   :data {:a :A :x x}
   :fallback (ctl/warn (str "Hello world" x))})