It's simple. I wanted to log to Graylog from my Clojure application. I banged my head numerous times trying to figure out how and why it did't want to work. Here's what I did to complete my mission. ## Graylog Go to **System > Inputs > Gelf UDP / TCP > Launch new input**. By default that input will be created on port **12201**. ## Using Timbre Add `[com.taoensso/timbre "4.10.0"]` to your project file. In the middleware or where you configure your logging on startup, add this configuration: ```clojure (ns wildfire.logging (:require [taoensso.timbre :as timbre] [taoensso.timbre.appenders.core :as appenders] [taoensso.timbre.appenders.3rd-party.gelf :as gelf])) ``` ```clojure ; This configuration includes the console and file appenders (defn init [config] (timbre/with-config (timbre/merge-config! {:level :info :ns-blacklist ["*datomic*"] :output-fn (partial timbre/default-output-fn {:stacktrace-fonts {}}) :appenders {:println (appenders/println-appender) :spit (appenders/spit-appender {:fname "log/wildfire.log" :append? true}) :gelf (gelf/gelf-appender "graylog.example.com" 12201 :udp)}}))) ``` ## Using Logstash Gelf I chose to give [mp911de/logstash-gelf](https://github.com/mp911de/logstash-gelf) a bash for now. Add a Gelf dependency to your project file `[biz.paluch.logging/logstash-gelf "1.12.0"]` Edit the configuration file: **env > [dev | prod] > resources > logback.xml** with the configuration for that Gelf dependency. ```xml udp:graylog.example.com 12201 1.1 wildfire true true true yyyy-MM-dd HH:mm:ss,SSS 8192 INFO

``` ## Things that went wrong - **I was using the wrong Graylog input**: I had setup a Syslog input on port **1514**. I was connecting to that instead of a Gelf input configured in Graylog. - **The Gelf reference did not exist in my project**: With Timbre working, I knew I was on the right track. Something was wrong with logback. An old appender existed in the configuration file and the namespace for that class was not referenced in the project. I found [mp911de/logstash-gelf](https://github.com/mp911de/logstash-gelf), updated my project.clj and it still didn't work. - **The configuration was invalid**: RTFM! I updated the configuration to use the properties defined in the spec and it worked. I am so new to configuring logging in Clojure that I confused myself silly. At least I now have a working implementation that makes me happy.