**[API docs](http://ptaoussanis.github.io/timbre/)** | **[CHANGELOG](https://github.com/ptaoussanis/timbre/blob/master/CHANGELOG.md)** | [contact & contributing](#contact--contributing) | [other Clojure libs](https://www.taoensso.com/clojure-libraries) | [Twitter](https://twitter.com/#!/ptaoussanis) | current [semantic](http://semver.org/) version: ```clojure [com.taoensso/timbre "2.7.1"] ; See CHANGELOG for breaking changes since 1.x ``` # Timbre, a (sane) Clojure logging & profiling library Logging with Java can be maddeningly, unnecessarily hard. Particularly if all you want is something *simple that works out-the-box*. Timbre is an attempt to make **simple logging simple** and more **complex logging reasonable**. No XML! ## What's in the box™? * Small, uncomplicated **all-Clojure** library. * **Super-simple map-based config**: no arcane XML or properties files! * **Low overhead** with dynamic logging level. * **No overhead** with compile-time logging level. (v2.6+) * Flexible **fn-centric appender model** with **middleware**. * Sensible built-in appenders including simple **email appender**. * Tunable **rate limit** and **asynchronous** logging support. * Robust **namespace filtering**. * **[tools.logging](https://github.com/clojure/tools.logging) support** (optional). * Dead-simple, logging-level-aware **logging profiler**. ## Getting started ### Dependencies Add the necessary dependency to your [Leiningen](http://leiningen.org/) `project.clj` and `require` the library in your ns: ```clojure [com.taoensso/timbre "2.7.1"] ; project.clj (ns my-app (:require [taoensso.timbre :as timbre :refer (trace debug info warn error fatal spy with-log-level)])) ; ns ``` ### Logging By default, Timbre gives you basic print output to `*out*`/`*err*` at a `debug` logging level: ```clojure (info "This will print") => nil %> 2012-May-28 17:26:11:444 +0700 localhost INFO [my-app] - This will print (spy :info (* 5 4 3 2 1)) => 120 %> 2012-May-28 17:26:14:138 +0700 localhost INFO [my-app] - (* 5 4 3 2 1) 120 (trace "This won't print due to insufficient logging level") => nil ``` There's little overhead for checking logging levels: ```clojure (time (trace (Thread/sleep 5000))) %> "Elapsed time: 0.054 msecs" (time (when false)) %> "Elapsed time: 0.051 msecs" ``` And _no_ overhead when using a compile-time logging level (set `TIMBRE_LOG_LEVEL` environment variable): ```clojure (time (dotimes [_ 1000000000] (trace (Thread/sleep 5000)))) %> "Elapsed time: 387.159 msecs" (time (dotimes [_ 1000000000] nil)) %> "Elapsed time: 389.231 msecs" ``` First-argument exceptions generate a stack trace: ```clojure (info (Exception. "Oh noes") "arg1" "arg2") %> 2012-May-28 17:35:16:132 +0700 localhost INFO [my-app] - arg1 arg2 java.lang.Exception: Oh noes NO_SOURCE_FILE:1 my-app/eval6409 Compiler.java:6511 clojure.lang.Compiler.eval <...> ``` ### Configuration Configuring Timbre couldn't be simpler. Let's check out (some of) the defaults: ```clojure @timbre/config => {:current-level :debug :ns-whitelist [] :ns-blacklist [] :middleware [] ; As of Timbre 1.4.0, see source for details :timestamp-pattern "yyyy-MMM-dd HH:mm:ss ZZ" :timestamp-locale nil :appenders {:standard-out { <...> } :spit { <...> } <...> } :shared-appender-config {}} ``` Easily adjust the current logging level: ```clojure (timbre/set-level! :warn) ``` And the default timestamp formatting for log messages: ```clojure (timbre/set-config! [:timestamp-pattern] "yyyy-MMM-dd HH:mm:ss ZZ") (timbre/set-config! [:timestamp-locale] (java.util.Locale/GERMAN)) ``` Filter logging output by namespaces: ```clojure (timbre/set-config! [:ns-whitelist] ["some.library.core" "my-app.*"]) ``` ### Built-in appenders #### File appender ```clojure (timbre/set-config! [:appenders :spit :enabled?] true) (timbre/set-config! [:shared-appender-config :spit-filename] "/path/my-file.log") ``` #### Email ([Postal](https://github.com/drewr/postal)) appender ```clojure ;; [com.draines/postal "1.9.2"] ; Add to project.clj dependencies ;; (:require [taoensso.timbre.appenders (postal :as postal-appender)]) ; Add to ns (timbre/set-config! [:appenders :postal] postal-appender/postal-appender) (timbre/set-config! [:shared-appender-config :postal] ^{:host "mail.isp.net" :user "jsmith" :pass "sekrat!!1"} {:from "me@draines.com" :to "foo@example.com"}) ;; Rate limit to one email per message per minute (timbre/set-config! [:appenders :postal :limit-per-msecs] 60000) ;; Make sure emails are sent asynchronously (timbre/set-config! [:appenders :postal :async?] true) ``` #### IRC ([irclj](https://github.com/flatland/irclj)) appender ```clojure ;; [irclj "0.5.0-alpha2"] ; Add to project.clj dependencies ;; (:require [taoensso.timbre.appenders (irc :as irc-appender)]) ; Add to ns (timbre/set-config! [:appenders :irc] irc-appender/irc-appender) (timbre/set-config! [:shared-appender-config :irc] {:host "irc.example.org" :port 6667 :nick "logger" :name "Logger" :chan "#logs"}) ``` #### Socket ([server-socket](https://github.com/technomancy/server-socket)) appender Listens on the specified interface (use :all for all interfaces, defaults to localhost if unspecified) and port. Connect with either of: ``` telnet localhost 9000 netcat localhost 9000 ``` ```clojure ;; [server-socket "1.0.0"] ; Add to project.clj dependencies ;; (:require [taoensso.timbre.appenders (socket :as socket-appender)]) ; Add to ns (timbre/set-config! [:appenders :socket] socket-appender/socket-appender) (timbre/set-config! [:shared-appender-config :socket] {:listen-addr :all :port 9000}) ``` #### MongoDB ([congomongo](https://github.com/aboekhoff/congomongo)) appender ```clojure ;; [congomongo "0.4.1"] ; Add to project.clj dependencies ;; (:require [taoensso.timbre.appenders (mongo :as mongo-appender)]) ; Add to ns (timbre/set-config! [:appenders :mongo] mongo-appender/mongo-appender) (timbre/set-config! [:shared-appender-config :mongo] {:db "logs" :collection "myapp" :server {:host "127.0.0.1" :port 27017}}) ``` ### Custom appenders Writing a custom appender is dead-easy: ```clojure (timbre/set-config! [:appenders :my-appender] {:doc "Hello-world appender" :min-level :debug :enabled? true :async? false :limit-per-msecs nil ; No rate limit :fn (fn [{:keys [ap-config level prefix throwable message] :as args}] (when-not (:my-production-mode? ap-config) (println prefix "Hello world!" message))) ``` And because appender fns are just regular Clojure fns, you have *unlimited power*: write to your database, send a message over the network, check some other state (e.g. environment config) before making a choice, etc. See the `timbre/config` docstring for more information on appenders. ## Profiling The usual recommendation for Clojure profiling is: use a good **JVM profiler** like [YourKit](http://www.yourkit.com/), [JProfiler](http://www.ej-technologies.com/products/jprofiler/overview.html), or [VisualVM](http://docs.oracle.com/javase/6/docs/technotes/guides/visualvm/index.html). And these certainly do the job. But as with many Java tools, they can be a little hairy and often heavy-handed - especially when applied to Clojure. Timbre includes an alternative. Let's add it to our app's `ns` declaration: ```clojure (:require [taoensso.timbre.profiling :as profiling :refer (p profile)]) ``` Wrap forms that you'd like to profile with the `p` macro and give them a name: ```clojure (defn my-fn [] (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))))) (my-fn) => 42 ``` The `profile` macro can now be used to log times for any wrapped forms: ```clojure (profile :info :Arithmetic (dotimes [n 100] (my-fn))) => "Done!" %> 2012-Jul-03 20:46:17 +0700 localhost INFO [my-app] - Profiling my-app/Arithmetic Name Calls Min Max MAD Mean Total% Total my-app/slow-sleep 100 2ms 2ms 31μs 2ms 57 231ms my-app/fast-sleep 100 1ms 1ms 27μs 1ms 29 118ms my-app/add 100 44μs 2ms 46μs 100μs 2 10ms my-app/sub 100 42μs 564μs 26μs 72μs 2 7ms my-app/div 100 54μs 191μs 17μs 71μs 2 7ms my-app/mult 100 31μs 165μs 11μs 44μs 1 4ms Unaccounted 6 26ms Total 100 405ms ``` It's important to note that Timbre profiling is fully **logging-level aware**: if the level is insufficient, you *won't pay for profiling*. Likewise, normal namespace filtering applies. (Performance characteristics for both checks are inherited from Timbre itself). And since `p` and `profile` **always return their body's result** regardless of whether profiling actually happens or not, it becomes feasible to use profiling more often as part of your normal workflow: just *leave profiling code in production as you do for logging code*. A simple **sampling profiler** is also available: `taoensso.timbre.profiling/sampling-profile`. ## This project supports the CDS and ![ClojureWerkz](https://raw.github.com/clojurewerkz/clojurewerkz.org/master/assets/images/logos/clojurewerkz_long_h_50.png) goals * [CDS](http://clojure-doc.org/), the **Clojure Documentation Site**, is a **contributer-friendly** community project aimed at producing top-notch, **beginner-friendly** Clojure tutorials and documentation. Awesome resource. * [ClojureWerkz](http://clojurewerkz.org/) is a growing collection of open-source, **batteries-included Clojure libraries** that emphasise modern targets, great documentation, and thorough testing. They've got a ton of great stuff, check 'em out! ## Contact & contribution Please use the [project's GitHub issues page](https://github.com/ptaoussanis/timbre/issues) for project questions/comments/suggestions/whatever **(pull requests welcome!)**. Am very open to ideas if you have any! Otherwise reach me (Peter Taoussanis) at [taoensso.com](https://www.taoensso.com) or on Twitter ([@ptaoussanis](https://twitter.com/#!/ptaoussanis)). Cheers! ## License Copyright © 2012, 2013 Peter Taoussanis. Distributed under the [Eclipse Public License](http://www.eclipse.org/legal/epl-v10.html), the same as Clojure.