Clojure Logging

logging.cli

(ns log-first.core
	 (:require [clojure.java.io :as io]
                   [taoensso.timbre :as timbre]
		   [taoensso.timbre.appenders.core :as appenders])
  (:gen-class))

;And into project.cli
; :dependencies [[org.clojure/clojure "1.10.1"]
;				 [com.taoensso/timbre "5.1.2"]]

(timbre/refer-timbre) ; set up timbre aliases

;; Disable logging to the console in timbre v4.0.0+:
(timbre/merge-config! {:appenders {:println {:enabled? false}}})

;; Create a "spit to file" appender in timbre v4.0.0+: 
(timbre/merge-config! {:appenders {:spit (appenders/spit-appender {:fname "log.txt"})}})

; Set the lowest-level to output as :debug
(timbre/set-level! :debug)

 ; Demonstrate logging with Timbre
  (trace "Hell, Timbre! trace")  ; will not be logged, below current log-level
  (debug "Hell, Timbre! debug")
  (info  "Hell, Timbre! info")
  (warn  "Hell, Timbre! warn")
  (error "Hell, Timbre! error")
  (fatal "Hell, Timbre! fatal")
  
   ; Demonstrate 3 arities of spy
  (info "Arg-1")
  (info "Arg-1" :Arg-2)
  (info "Arg-1" :Arg-2 ["Arg-3"] )
  (info "Arg-1" :Arg-2 ["Arg-3"] {:Arg 4} )
  
    ; Demonstrate 3 arities of spy
  (assert (= {:a 1}     (spy :info "Spy returns the last value" {:a 1} )))
  (assert (= 42         (spy (* 6 7) ))) ; no level implies :debug
  (assert (= 42         (spy :warn (* 6 7))))
  (assert (= {:a 1}     (spy :error "optional message" {:a 1} )))

  ; Even exceptions look nice in the logs
  (error (Exception. "Doh!") "Any extra" :items {:go "here"} )