**[CHANGELOG]** | [API] | current [Break Version]: ```clojure [com.taoensso/timbre "4.2.1"] ; Stable [com.taoensso/timbre "4.3.0-RC1"] ; Dev, see CHANGELOG for details ``` # Timbre ## A pure Clojure/Script logging library Java logging is a mess of complexity that buys you _nothing_. It can be comically hard to get even the simplest logging working, and it's no better at scale. Timbre offers an **all Clojure/Script** alternative that **works out the box**. It's fast, deeply flexible, and easy to configure. **No XML!** ## Features * Full **Clojure** + **ClojureScript** support (v4+) * No XML or properties files. **A single, simple config map**, and you're set * Deeply flexible **fn appender model** with **middleware** * **Great performance** at any scale * Filter logging by levels and **namespace whitelist/blacklist patterns** * **Zero overhead** with **complete Clj+Cljs elision** for compile-time level/ns filters * Useful built-in appenders for **out-the-box** Clj+Cljs logging * Powerful, easy-to-configure per-appender **rate limits** and **async logging** * [Logs as Clojure values][] (v3+) * [tools.logging] support (optional, useful when integrating with legacy logging systems) * Level and ns-filter aware **logging profiler** * Small, simple, cross-platform codebase ## 3rd-party tools, appenders, etc. Link | Description ------------------------ | ----------------------------------------------------- [@palletops/log-config] | Library to help manage Timbre logging config [@fzakaria/slf4j-timbre] | Route log4j/logback/sfl4j log output to Timbre Your link here? | **PR's welcome!** ## Getting started Add the necessary dependency to your project: ```clojure [com.taoensso/timbre "4.2.1"] ``` And setup your namespace imports: ```clojure (ns my-clj-ns ; Clojure namespace (:require [taoensso.timbre :as timbre :refer (log trace debug info warn error fatal report logf tracef debugf infof warnf errorf fatalf reportf spy get-env log-env)] [taoensso.timbre.profiling :as profiling :refer (pspy pspy* profile defnp p p*)])) (ns my-cljs-ns ; ; ClojureScript namespace (:require [taoensso.timbre :as timbre :refer-macros (log trace debug info warn error fatal report logf tracef debugf infof warnf errorf fatalf reportf spy get-env log-env)])) ``` > You can also call `(timbre/refer-timbre)` to configure Clj ns referrals **automatically** ### Logging By default, Timbre gives you basic `println` and `js/console` (v4+) output at a `:debug` log level: ```clojure (info "This will print") => nil %> 15-Jun-13 19:18:33 localhost INFO [my-app.core] - This will print (spy :info (* 5 4 3 2 1)) => 120 %> 15-Jun-13 19:19:13 localhost INFO [my-app.core] - (* 5 4 3 2 1) => 120 (defn my-mult [x y] (info "Lexical env:" (get-env)) (* x y)) => #'my-mult (my-mult 4 7) => 28 %> 15-Jun-13 19:21:53 localhost INFO [my-app.core] - Lexical env: {x 4, y 7} (trace "This won't print due to insufficient log level") => nil ``` First-argument exceptions generate a nicely cleaned-up stack trace using [io.aviso.exception][] (Clj only): ```clojure (info (Exception. "Oh noes") "arg1" "arg2") %> 15-Jun-13 19:22:55 localhost INFO [my-app.core] - arg1 arg2 java.lang.Exception: On noes ``` Other utils include: `log-errors`, `log-and-rethrow-errors`, `logged-future`, and `handle-uncaught-jvm-exceptions!` (please see the [API] for details). #### Disabling stacktrace colors ANSI colors are enabled by default for stacktraces. To turn these off (e.g. for log files or emails), you can add the following entry to your top-level config **or** individual appender map/s: ```clojure :output-fn (partial timbre/default-output-fn {:stacktrace-fonts {}}) ``` ### Configuration This is the biggest win over Java logging IMO. Here's `timbre/example-config` (also Timbre's default config): > The example below shows config for **Timbre v4**. See [here](https://github.com/ptaoussanis/timbre/tree/v3.4.0#configuration) for an example of **Timbre v3** config. ```clojure (def example-config "Example (+default) Timbre v4 config map. APPENDERS An appender is a map with keys: :min-level ; Level keyword, or nil (=> no minimum level) :enabled? ; :async? ; Dispatch using agent? Useful for slow appenders :rate-limit ; [[ncalls-limit window-ms] <...>], or nil :output-fn ; Optional override for inherited (fn [data]) -> string :fn ; (fn [data]) -> side effects, with keys described below An appender's fn takes a single data map with keys: :config ; Entire config map (this map, etc.) :appender-id ; Id of appender currently dispatching :appender ; Entire map of appender currently dispatching :instant ; Platform date (java.util.Date or js/Date) :level ; Keyword :error-level? ; Is level e/o #{:error :fatal}? :?ns-str ; String, or nil :?file ; String, or nil ; Waiting on CLJ-865 :?line ; Integer, or nil ; Waiting on CLJ-865 :?err_ ; Delay - first-arg platform error, or nil :vargs_ ; Delay - raw args vector :hostname_ ; Delay - string (clj only) :msg_ ; Delay - args string :timestamp_ ; Delay - string :output-fn ; (fn [data]) -> formatted output string ; (see `default-output-fn` for details) :context ; *context* value at log time (see `with-context`) :profile-stats ; From `profile` macro MIDDLEWARE Middleware are simple (fn [data]) -> ?data fns (applied left->right) that transform the data map dispatched to appender fns. If any middleware returns nil, NO dispatching will occur (i.e. the event will be filtered). The `example-config` source code contains further settings and details. See also `set-config!`, `merge-config!`, `set-level!`." {:level :debug ; e/o #{:trace :debug :info :warn :error :fatal :report} ;; Control log filtering by namespaces/patterns. Useful for turning off ;; logging in noisy libraries, etc.: :ns-whitelist [] #_["my-app.foo-ns"] :ns-blacklist [] #_["taoensso.*"] :middleware [] ; (fns [data]) -> ?data, applied left->right ;; Clj only: :timestamp-opts default-timestamp-opts ; {:pattern _ :locale _ :timezone _} :output-fn default-output-fn ; (fn [data]) -> string :appenders {:example-println-appender ; Appender id ;; Appender definition (just a map): {:enabled? true :async? false :min-level nil :rate-limit [[1 250] [10 5000]] ; 1/250ms, 10/5s :output-fn :inherit :fn ; Appender's fn (fn [data] (let [{:keys [output-fn]} data formatted-output-str (output-fn data)] (println formatted-output-str)))}}}) ``` A few things to note: * Appenders are _trivial_ to write & configure - **they're just fns**. It's Timbre's job to dispatch useful args to appenders when appropriate, it's their job to do something interesting with them. * Being 'just fns', appenders have basically limitless potential: write to your database, send a message over the network, check some other state (e.g. environment config) before making a choice, etc. #### Log levels and ns filters The **log level** may be set: * At compile-time: (`TIMBRE_LEVEL` environment variable) * Statically using: `timbre/set-level!`/`timbre/merge-level!` * Dynamically using: `timbre/with-level` The **ns filters** may be set: * At compile-time: (`TIMBRE_NS_WHITELIST`, `TIMBRE_NS_BLACKLIST` env vars) * Statically using: `timbre/set-config!`/`timbre/merge-config!` * Dynamically using: `timbre/with-config` There are also variants of the core logging macros that take an **explicit config arg**: ```clojure (timbre/log* <& args>) ; or (timbre/logf* <& args>) ``` Logging calls excluded by a compile-time option (e.g. during Cljs compilation) will be **entirely elided from your codebase**, e.g.: ```bash #!/bin/bash # edn values welcome: export TIMBRE_LEVEL=':warn' # Elide all lower logging calls export TIMBRE_NS_WHITELIST='["my-app.*"]' # Elide all other ns logging calls export TIMBRE_NS_BLACKLIST='["my-app.foo" "my-app.bar.*"]' lein cljsbuild once # Compile js with appropriate logging calls excluded lein uberjar # Compile jar '' ``` ### Built-in appenders #### Redis ([Carmine]) appender (v3+) ```clojure ;; [com.taoensso/carmine ] ; Add to project.clj deps ;; (:require [taoensso.timbre.appenders (carmine :as car-appender)]) ; Add to ns (timbre/merge-config! {:appenders {:carmine (car-appender/carmine-appender)}}) ``` This gives us a high-performance Redis appender: * **All raw logging args are preserved** in serialized form (**even errors!**) * Only the most recent instance of each **unique entry** is kept (hash fn used to determine uniqueness is configurable) * Configurable number of entries to keep per log level * **Log is just a value**: a vector of Clojure maps: **query+manipulate with standard seq fns**: group-by hostname, sort/filter by ns & severity, explore exception stacktraces, filter by raw arguments, stick into or query with **Datomic**, etc. A simple query utility is provided: `car-appender/query-entries`. #### Email ([Postal]) appender ```clojure ;; [com.draines/postal ] ; Add to project.clj deps ;; (:require [taoensso.timbre.appenders (postal :as postal-appender)]) ; Add to ns (timbre/merge-config! {:appenders {:postal (postal-appender/postal-appender ^{:host "mail.isp.net" :user "jsmith" :pass "sekrat!!1"} {:from "me@draines.com" :to "foo@example.com"})}}) ``` #### File appender ```clojure ;; (:require [taoensso.timbre.appenders.core :as appenders]) ; Add to ns (timbre/merge-config! {:appenders {:spit (appenders/spit-appender {:fname "/path/my-file.log"})}}) ``` #### Other included appenders A number of 3rd-party appenders are included out-the-box [here](https://github.com/ptaoussanis/timbre/tree/master/src/taoensso/timbre/appenders/3rd_party). **Please see the relevant docstring for details**. Thank you to the respective authors! Just give me a shout if you've got an appender you'd like to have added. ## Profiling (currently Clj only) The usual recommendation for Clojure profiling is: use a good **JVM profiler** like [YourKit], [JProfiler], or [VisualVM]. 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. 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 ``` You can also use the `defnp` macro to conveniently wrap whole fns. Timbre profiling is fully **log level & ns filter aware**: if the level is insufficient or ns filtered, you **won't pay for profiling**. And since `p` and `profile` **always return their body's result**, it becomes feasible to use profiling more often as part of your normal workflow: just *leave profiling code in production as you do logging code*. A simple sampling profiler is also included. ## This project supports the ![ClojureWerkz-logo] goals * [ClojureWerkz] is a growing collection of open-source, **batteries-included Clojure libraries** that emphasise modern targets, great documentation, and thorough testing. ## Contacting me / contributions Please use the project's [GitHub issues page] for all questions, ideas, etc. **Pull requests welcome**. See the project's [GitHub contributors page] for a list of contributors. Otherwise, you can reach me at [Taoensso.com]. Happy hacking! \- [Peter Taoussanis] ## License Distributed under the [EPL v1.0] \(same as Clojure). Copyright © 2015-2016 [Peter Taoussanis]. [Taoensso.com]: https://www.taoensso.com [Peter Taoussanis]: https://www.taoensso.com [@ptaoussanis]: https://www.taoensso.com [More by @ptaoussanis]: https://www.taoensso.com [Break Version]: https://github.com/ptaoussanis/encore/blob/master/BREAK-VERSIONING.md [CHANGELOG]: https://github.com/ptaoussanis/timbre/releases [API]: http://ptaoussanis.github.io/timbre/ [GitHub issues page]: https://github.com/ptaoussanis/timbre/issues [GitHub contributors page]: https://github.com/ptaoussanis/timbre/graphs/contributors [EPL v1.0]: https://raw.githubusercontent.com/ptaoussanis/timbre/master/LICENSE [Hero]: https://raw.githubusercontent.com/ptaoussanis/timbre/master/hero.png "Title" [Logs as Clojure values]: #redis-carmine-appender-v3 [@palletops/log-config]: https://github.com/palletops/log-config [@fzakaria/slf4j-timbre]: https://github.com/fzakaria/slf4j-timbre [tools.logging]: https://github.com/clojure/tools.logging [io.aviso.exception]: https://github.com/AvisoNovate/pretty [Carmine]: https://github.com/ptaoussanis/carmine [Postal]: https://github.com/drewr/postal [YourKit]: http://www.yourkit.com/) [JProfiler]: http://www.ej-technologies.com/products/jprofiler/overview.html [VisualVM]: http://docs.oracle.com/javase/6/docs/technotes/guides/visualvm/index.html [ClojureWerkz-logo]: https://raw.github.com/clojurewerkz/clojurewerkz.org/master/assets/images/logos/clojurewerkz_long_h_50.png [ClojureWerkz]: http://clojurewerkz.org/