mirror of https://github.com/status-im/timbre.git
360 lines
14 KiB
Markdown
360 lines
14 KiB
Markdown
<a href="https://www.taoensso.com" title="More stuff by @ptaoussanis at www.taoensso.com">
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<img src="https://www.taoensso.com/taoensso-open-source.png" alt="Taoensso open-source" width="400"/></a>
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**[CHANGELOG]** | [API] | current [Break Version]:
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```clojure
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[com.taoensso/timbre "4.10.0"] ; Please check CHANGELOG for details
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```
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> Please consider helping to [support my continued open-source Clojure/Script work]?
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>
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> Even small contributions can add up + make a big difference to help sustain my time writing, maintaining, and supporting Timbre and other Clojure/Script libraries. **Thank you!**
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>
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> \- Peter Taoussanis
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# Timbre
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## A pure Clojure/Script logging library
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Java logging is a Kafkaesque mess of complexity that buys you _nothing_. It can be comically hard to get even the simplest logging working, and it just gets worse at scale.
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Timbre offers an **all Clojure/Script** alternative that's fast, deeply flexible, easy to configure, and that **works out the box**. No XML.
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Supports optional interop with [tools.logging](https://github.com/ptaoussanis/timbre/blob/master/src/taoensso/timbre/tools/logging.clj) and [log4j/logback/slf4j](https://github.com/fzakaria/slf4j-timbre).
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Happy hacking!
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## Features
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* Full **Clojure** + **ClojureScript** support (v4+).
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* No XML or properties files. **A single, simple config map**, and you're set.
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* Simple, flexible **fn appender model** with **middleware**.
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* **Great performance** at any scale.
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* Filter logging by levels, **namespace whitelist/blacklist patterns**, and more.
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* **Zero overhead** with **complete Clj+Cljs elision** for compile-time level/ns filters.
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* Useful built-in appenders for **out-the-box** Clj+Cljs logging.
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* Powerful, easy-to-configure **rate limits** and **async logging**.
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* [Logs as Clojure values][] (v3+).
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* Small, simple, cross-platform codebase.
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## 3rd-party tools, appenders, etc.
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Link | Description
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------------------------ | -----------------------------------------------------
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[@fzakaria/slf4j-timbre] | Route log4j/logback/sfl4j log output to Timbre
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[@palletops/log-config] | Library to help manage Timbre logging config
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Your link here? | **PR's welcome!**
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## Getting started
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Add the necessary dependency to your project:
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```clojure
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[com.taoensso/timbre "4.10.0"]
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```
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And setup your namespace imports:
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```clojure
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(ns my-clj-ns ; Clojure namespace
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(:require
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[taoensso.timbre :as timbre
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:refer [log trace debug info warn error fatal report
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logf tracef debugf infof warnf errorf fatalf reportf
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spy get-env]]))
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(ns my-cljs-ns ; ; ClojureScript namespace
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(:require
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[taoensso.timbre :as timbre
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:refer-macros [log trace debug info warn error fatal report
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logf tracef debugf infof warnf errorf fatalf reportf
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spy get-env]]))
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```
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> You can also call `(timbre/refer-timbre)` to configure Clj ns referrals **automatically**.
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### Logging
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By default, Timbre gives you basic `println` and `js/console` (v4+) output at a `:debug` log level:
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```clojure
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(info "This will print") => nil
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%> 15-Jun-13 19:18:33 localhost INFO [my-app.core] - This will print
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(spy :info (* 5 4 3 2 1)) => 120
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%> 15-Jun-13 19:19:13 localhost INFO [my-app.core] - (* 5 4 3 2 1) => 120
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(defn my-mult [x y] (info "Lexical env:" (get-env)) (* x y)) => #'my-mult
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(my-mult 4 7) => 28
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%> 15-Jun-13 19:21:53 localhost INFO [my-app.core] - Lexical env: {x 4, y 7}
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(trace "This won't print due to insufficient log level") => nil
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```
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First-argument exceptions generate a nicely cleaned-up stack trace using [io.aviso.exception][] (Clj only):
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```clojure
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(info (Exception. "Oh noes") "arg1" "arg2")
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%> 15-Jun-13 19:22:55 localhost INFO [my-app.core] - arg1 arg2
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java.lang.Exception: On noes
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<Stacktrace>
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```
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Other utils include: `log-errors`, `log-and-rethrow-errors`, `logged-future`, and `handle-uncaught-jvm-exceptions!` (please see the [API] for details).
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#### Disabling stacktrace colors
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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:
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```clojure
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:output-fn (partial timbre/default-output-fn {:stacktrace-fonts {}})
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```
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And/or you can set the `TIMBRE_DEFAULT_STACKTRACE_FONTS` environment variable (supports edn).
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### Data flow
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Timbre's inherently a very simple design, no magic. It's just Clojure data and functions:
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1. Unfiltered logging calls generate a **data map**: `{:level _ :?ns-str _ ...}`
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2. The resulting data map passes through any **middleware fns**, `(fn [data]) -> ?data`
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3. The resulting data map is sent to all **appender fns**, `(fn [data]) -> ?effects`
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### Configuration
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This is the biggest win over Java logging IMO.
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**All** of Timbre's behaviour is controlled through a single, simple Clojure map.
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> See `timbre/example-config` for Timbre's default config map
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```clojure
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(def example-config
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"An example Timbre v4 config map.
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APPENDERS
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An appender is a map with keys:
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:min-level ; Level keyword, or nil (=> no minimum level)
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:enabled? ;
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:async? ; Dispatch using agent? Useful for slow appenders (clj only)
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:rate-limit ; [[ncalls-limit window-ms] <...>], or nil
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:output-fn ; Optional override for inherited (fn [data]) -> string
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:timestamp-opts ; Optional override for inherited {:pattern _ :locale _ :timezone _} (clj only)
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:ns-whitelist ; Optional, stacks with active config's whitelist
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:ns-blacklist ; Optional, stacks with active config's blacklist
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:fn ; (fn [data]) -> side effects, with keys described below
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An appender's fn takes a single data map with keys:
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:config ; Entire config map (this map, etc.)
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:appender-id ; Id of appender currently dispatching
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:appender ; Entire map of appender currently dispatching
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:instant ; Platform date (java.util.Date or js/Date)
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:level ; Keyword
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:error-level? ; Is level e/o #{:error :fatal}?
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:?ns-str ; String, or nil
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:?file ; String, or nil
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:?line ; Integer, or nil ; Waiting on CLJ-865
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:?err ; First-arg platform error, or nil
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:vargs ; Vector of raw args
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:output_ ; Forceable - final formatted output string created
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; by calling (output-fn <this-data-map>)
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:msg_ ; Forceable - args as a string
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:timestamp_ ; Forceable - string (clj only)
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:hostname_ ; Forceable - string (clj only)
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:output-fn ; (fn [data]) -> formatted output string
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; (see `default-output-fn` for details)
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:context ; *context* value at log time (see `with-context`)
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**NB** - any keys not specifically documented here should be
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considered private / subject to change without notice.
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MIDDLEWARE
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Middleware are simple (fn [data]) -> ?data fns (applied left->right) that
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transform the data map dispatched to appender fns. If any middleware
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returns nil, NO dispatch will occur (i.e. the event will be filtered).
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The `example-config` source code contains further settings and details.
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See also `set-config!`, `merge-config!`, `set-level!`."
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{:level :debug ; e/o #{:trace :debug :info :warn :error :fatal :report}
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;; Control log filtering by namespaces/patterns. Useful for turning off
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;; logging in noisy libraries, etc.:
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:ns-whitelist [] #_["my-app.foo-ns"]
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:ns-blacklist [] #_["taoensso.*"]
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:middleware [] ; (fns [data]) -> ?data, applied left->right
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;; Clj only:
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:timestamp-opts default-timestamp-opts ; {:pattern _ :locale _ :timezone _}
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:output-fn default-output-fn ; (fn [data]) -> string
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:appenders
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{;; The standard println appender:
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;; :println (println-appender {:stream :auto})
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:an-example-custom-println-appender
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;; Inline appender definition (just a map):
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{:enabled? true
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:async? false
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:min-level nil
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:rate-limit [[1 250] [10 5000]] ; 1/250ms, 10/5s
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:output-fn :inherit
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:fn ; Appender's (fn [data]) -> side effects
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(fn [data]
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(let [{:keys [output_]} data
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formatted-output-str (force output_)]
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(println formatted-output-str)))}}})
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```
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A few things to note:
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* 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.
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* 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.
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#### Log levels and ns filters
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The **log level** may be set:
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* At compile-time: (`TIMBRE_LEVEL` environment variable).
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* Statically using: `timbre/set-level!`/`timbre/merge-level!`.
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* Dynamically using: `timbre/with-level`.
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The **ns filters** may be set:
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* At compile-time: (`TIMBRE_NS_WHITELIST`, `TIMBRE_NS_BLACKLIST` env vars).
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* Statically using: `timbre/set-config!`/`timbre/merge-config!`.
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* Dynamically using: `timbre/with-config`.
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There are also variants of the core logging macros that take an **explicit config arg**:
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```clojure
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(timbre/log* <config-map> <level> <& args>) ; or
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(timbre/logf* <config-map> <level> <& args>)
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```
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Logging calls excluded by a compile-time option (e.g. during Cljs compilation) will be **entirely elided from your codebase**, e.g.:
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```bash
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#!/bin/bash
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# edn values welcome:
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export TIMBRE_LEVEL=':warn' # Elide all lower logging calls
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export TIMBRE_NS_WHITELIST='["my-app.*"]' # Elide all other ns logging calls
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export TIMBRE_NS_BLACKLIST='["my-app.foo" "my-app.bar.*"]'
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lein cljsbuild once # Compile js with appropriate logging calls excluded
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lein uberjar # Compile jar ''
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```
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### Built-in appenders
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#### Basic file appender
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```clojure
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;; (:require [taoensso.timbre.appenders.core :as appenders]) ; Add to ns
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(timbre/merge-config!
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{:appenders {:spit (appenders/spit-appender {:fname "/path/my-file.log"})}})
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;; (timbre/merge-config! {:appenders {:spit {:enabled? false}}} ; To disable
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;; (timbre/merge-config! {:appenders {:spit nil}} ; To remove entirely
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```
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#### Redis ([Carmine]) appender (v3+)
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```clojure
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;; [com.taoensso/carmine <latest-version>] ; Add to project.clj deps
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;; (:require [taoensso.timbre.appenders (carmine :as car-appender)]) ; Add to ns
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(timbre/merge-config! {:appenders {:carmine (car-appender/carmine-appender)}})
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```
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This gives us a high-performance Redis appender:
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* **All raw logging args are preserved** in serialized form (even errors).
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* Configurable number of entries to keep per log level.
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* Only the most recent instance of each **unique entry** is kept.
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* Resulting **log is just a Clojure value**: a vector of log entries (maps).
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Clojure has a rich selection of built-in and 3rd party tools for querying values like this.
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See also `car-appender/query-entries`.
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#### Email ([Postal]) appender
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```clojure
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;; [com.draines/postal <latest-version>] ; Add to project.clj deps
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;; (:require [taoensso.timbre.appenders (postal :as postal-appender)]) ; Add to ns
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(timbre/merge-config!
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{:appenders
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{:postal
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(postal-appender/postal-appender
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^{:host "mail.isp.net" :user "jsmith" :pass "sekrat!!1"}
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{:from "me@draines.com" :to "foo@example.com"})}})
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```
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#### Other included appenders
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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**. Thanks goes to the respective authors!
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Just give me a shout if you've got an appender you'd like to have added.
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## Profiling
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As of v4.6.0, Timbre's profiling features have been enhanced and exported to a dedicated profiling library called [Tufte].
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Timbre's old profiling features **will be kept for backwards compatibility** throughout v4.x, but future development will be focused exclusively on Tufte.
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Tufte has out-the-box support for integration with Timbre, and [migration](https://github.com/ptaoussanis/tufte#how-does-tufte-compare-to-the-profiling-in-timbre) is usually simple.
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Sorry for the inconvenience!
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## This project supports the ![ClojureWerkz-logo] goals
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[ClojureWerkz] is a growing collection of open-source, **batteries-included Clojure libraries** that emphasise modern targets, great documentation, and thorough testing.
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## Contacting me / contributions
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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.
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Otherwise, you can reach me at [Taoensso.com]. Happy hacking!
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\- [Peter Taoussanis]
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## License
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Distributed under the [EPL v1.0] \(same as Clojure).
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Copyright © 2015-2016 [Peter Taoussanis].
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<!--- Standard links -->
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[Taoensso.com]: https://www.taoensso.com
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[Peter Taoussanis]: https://www.taoensso.com
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[@ptaoussanis]: https://www.taoensso.com
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[More by @ptaoussanis]: https://www.taoensso.com
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[Break Version]: https://github.com/ptaoussanis/encore/blob/master/BREAK-VERSIONING.md
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[support my continued open-source Clojure/Script work]: http://taoensso.com/clojure/backers
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<!--- Standard links (repo specific) -->
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[CHANGELOG]: https://github.com/ptaoussanis/timbre/releases
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[API]: http://ptaoussanis.github.io/timbre/
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[GitHub issues page]: https://github.com/ptaoussanis/timbre/issues
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[GitHub contributors page]: https://github.com/ptaoussanis/timbre/graphs/contributors
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[EPL v1.0]: https://raw.githubusercontent.com/ptaoussanis/timbre/master/LICENSE
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[Hero]: https://raw.githubusercontent.com/ptaoussanis/timbre/master/hero.png "Title"
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<!--- Unique links -->
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[logging profiler]: #profiling
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[Logs as Clojure values]: #redis-carmine-appender-v3
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[@palletops/log-config]: https://github.com/palletops/log-config
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[@fzakaria/slf4j-timbre]: https://github.com/fzakaria/slf4j-timbre
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[io.aviso.exception]: https://github.com/AvisoNovate/pretty
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[Carmine]: https://github.com/ptaoussanis/carmine
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[Tufte]: https://github.com/ptaoussanis/tufte
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[Postal]: https://github.com/drewr/postal
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[ClojureWerkz-logo]: https://raw.github.com/clojurewerkz/clojurewerkz.org/master/assets/images/logos/clojurewerkz_long_h_50.png
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[ClojureWerkz]: http://clojurewerkz.org/
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