A short template on the use of Timbre for Clojure logging
Just execute using lein:
> lein run Hello, World! Shutting down...
> cat log.txt
2014-Oct-30 23:00:11 -0700 localhost.localdomain INFO [log-timbre.core] - Hello, Timbre! info
2014-Oct-30 23:00:11 -0700 localhost.localdomain INFO [log-timbre.core] - Hello, Timbre! spy :info Hello, Timbre! spy :info
2014-Oct-30 23:00:11 -0700 localhost.localdomain DEBUG [log-timbre.core] - Hello, Timbre! debug
2014-Oct-30 23:00:11 -0700 localhost.localdomain INFO [log-timbre.core] - arg2 arg3
java.lang.Exception: Doh!
log-timbre.core/-main core.clj: 36
clojure.lang.RestFn.invoke RestFn.java: 397
clojure.lang.Var.invoke Var.java: 375
user/eval3 form-init6280606650468310964.clj: 1
clojure.lang.Compiler.eval Compiler.java: 6767
clojure.lang.Compiler.eval Compiler.java: 6757
clojure.lang.Compiler.load Compiler.java: 7194
clojure.lang.Compiler.loadFile Compiler.java: 7150
clojure.main/load-script main.clj: 274
clojure.main/init-opt main.clj: 279
clojure.main/initialize main.clj: 307
clojure.main/null-opt main.clj: 342
clojure.main/main main.clj: 420
clojure.lang.RestFn.invoke RestFn.java: 421
clojure.lang.Var.invoke Var.java: 383
clojure.lang.AFn.applyToHelper AFn.java: 156
clojure.lang.Var.applyTo Var.java: 700
clojure.main.main main.java: 37
2014-Oct-30 23:00:12 -0700 localhost.localdomain INFO [log-timbre.core] - (my-fn) => 42
2014-Oct-30 23:00:12 -0700 localhost.localdomain INFO [log-timbre.core] - Profiling: :log-timbre.core/Arithmetic
Id nCalls Min Max MAD Mean Time% Time
:log-timbre.core/slow-sleep 100 2.0ms 5.0ms 99.0μs 2.0ms 47 213.0ms
:log-timbre.core/fast-sleep 100 1.0ms 5.0ms 79.0μs 1.0ms 24 111.0ms
:log-timbre.core/div 100 68.0μs 1.0ms 85.0μs 234.0μs 5 23.0ms
:log-timbre.core/mult 100 42.0μs 544.0μs 54.0μs 149.0μs 3 15.0ms
:log-timbre.core/sub 100 43.0μs 464.0μs 59.0μs 143.0μs 3 14.0ms
:log-timbre.core/add 100 55.0μs 379.0μs 45.0μs 136.0μs 3 14.0ms
Clock Time 100 457.0ms
Accounted Time 85 390.0ms
(ns log-timbre.core
(:require [clojure.java.io :as io]
[taoensso.timbre :as timbre] )
(:gen-class))
; Set up the name of the log output file and delete any contents from previous runs (the
; default is to continually append all runs to the file).
(def log-file-name "log.txt")
(io/delete-file log-file-name :quiet)
(timbre/refer-timbre) ; set up timbre aliases
; The default setup is simple console logging. We with to turn off console logging and
; turn on file logging to our chosen filename.
(timbre/set-config! [:appenders :standard-out :enabled?] false)
(timbre/set-config! [:appenders :spit :enabled?] true)
(timbre/set-config! [:shared-appender-config :spit-filename] log-file-name)
(timbre/set-config! [:shared-appender-config :spit-filename] log-file-name)
; Set the lowest-level to output as :debug
(timbre/set-level! :debug)
(defn my-fn
"A simple fn to demonstrate profiling"
[]
(let [nums (vec (range 1000))]
(+ (p :fast-sleep (Thread/sleep 1) 10)
(p :slow-sleep (Thread/sleep 2) 32)
(p :add (reduce + nums))
(p :sub (reduce - nums))
(p :mult (reduce * nums))
(p :div (reduce / nums)))))
(defn -main []
(println "Hello, World!") ; a short message to the console
; Demonstrate logging with Timbre
(trace "Hello, Timbre! trace") ; will not be logged, below current log-level
(debug "Hello, Timbre! debug")
(info "Hello, Timbre! info")
(warn "Hello, Timbre! warn")
(error "Hello, Timbre! error")
(fatal "Hello, Timbre! fatal")
; Demonstrate multiple arities
(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"} )
; Demonstrate profiling with Timbre
(info "(my-fn) => " (my-fn))
(profile :info :Arithmetic (dotimes [n 100] (my-fn)))
; Note that when using "lein run", we must place a call to (shutdown-agents) at the end of
; the main program. If this is omitted there is a one minute delay before (non-daemon)
; agent threads will shutdown. For some reason, however, this is not required for "lein
; test". Presumably "lein test" either calls either (shutdown-agents) or (System/exit 0)
; when it is complete.
(shutdown-agents)
)