Add Syslog back-end

project.clj

@@ -13,6 +13,7 @@
   :dependencies
   [[org.clojure/clojure "1.5.1"]
    [com.taoensso/encore "2.91.0"]
+   [net.java.dev.jna/jna "3.4.0"]
    [io.aviso/pretty     "0.1.33"]]
 
   :plugins
@@ -44,6 +45,7 @@
      [cheshire                "5.6.3"]
      [ymilky/franzy           "0.0.1"]
      [com.newrelic.agent.java/newrelic-agent "3.31.1"]
+     [net.java.dev.jna/jna    "3.4.0"]
      [raven-clj               "1.5.0"]]}
 
    :dev

src/taoensso/timbre/appenders/3rd_party/syslog_appender.clj

@@ -0,0 +1,96 @@
+(ns taoensso.timbre.appenders.3rd-party.syslog-appender
+  "Requires https://github.com/java-native-access/jna"
+  {:author "Audrius Molis @audriu"
+   :inspired-by "https://github.com/joshrotenberg/brolog"}
+  (:require
+   [taoensso.timbre :as timbre])
+  (:import [com.sun.jna Function]))
+
+(def ^:private timbre->syslog-priority
+  "Map timbre log levels to syslog levels"
+  {:trace  7 ;debug
+   :debug  7 ;debug
+   :info   6 ;info
+          ;5 ;notice
+   :warn   4 ;warning
+   :error  3 ;err
+          ;2 ;crit
+   :report 1 ;alert
+   :fatal  0 ;emerg
+   })
+
+(defn- <<3 [n] (bit-shift-left n 3))
+
+(def ^:private facility-map
+  {:log-kern     (<<3 0)
+   :log-user     (<<3 1)
+   :log-mail     (<<3 2)
+   :log-daemon   (<<3 3)
+   :log-auth     (<<3 4)
+   :log-syslog   (<<3 5)
+   :log-lpr      (<<3 6)
+   :log-news     (<<3 7)
+   :log-uucp     (<<3 8)
+   :log-cron     (<<3 9)
+   :log-authpriv (<<3 10)
+   :log-ftp      (<<3 11)
+   :log-ntp      (<<3 12)
+   :log-security (<<3 13)
+   :log-local0   (<<3 16)
+   :log-local1   (<<3 17)
+   :log-local2   (<<3 18)
+   :log-local3   (<<3 19)
+   :log-local4   (<<3 20)
+   :log-local5   (<<3 21)
+   :log-local6   (<<3 22)
+   :log-local7   (<<3 23)})
+
+(def ^:private options
+  {:log-pid    (byte 0x01) ;; log the pid
+   :log-cons   (byte 0x02) ;; log to the console if errors in sending
+   :log-odelay (byte 0x04) ;; delay open until first call
+   :log-ndelay (byte 0x08) ;; don't delay open
+   :log-nowait (byte 0x10) ;; don't wait for console forks (deprecated)
+   :log-perror (byte 0x20) ;; log to stderr as well
+   })
+
+(defn- openlog
+  [ident option facility]
+  (let [f (com.sun.jna.Function/getFunction "c" "openlog")]
+    (.invoke f Integer (to-array [ident option facility]))))
+
+(defn- syslog
+  [priority format & args]
+  (let [f (com.sun.jna.Function/getFunction "c" "syslog")]
+    (.invoke f Integer (to-array (flatten [priority format args])))))
+
+(defn- log-message [ident syslog-options facility data]
+  (openlog ident syslog-options facility)
+  (let [{:keys [level vargs]} data
+        priority (timbre->syslog-priority level)]
+    (syslog priority (str vargs))))
+
+(defn syslog-appender
+  "Returns a syslog appender. All parameters are optional.
+  (journald-appender
+    {:ident \"my-app\"
+     :syslog-options bytemap of values from 'options' map.
+     :facility :log-user}})"
+  [config]
+  (let [{:keys [ident syslog-options facility]
+         :or {facility :log-user}} config
+        facility (facility-map facility)]
+    {:enabled?   true
+     :async?     true
+     :min-level  nil
+     :output-fn  :inherit
+     :fn (fn [data] (log-message ident syslog-options facility data))}))
+
+(comment
+  (timbre/merge-config!
+   {:appenders
+    {:syslog-appender
+     (taoensso.timbre.appenders.3rd-party.syslog-appender/syslog-appender
+      {:ident "my-app"
+       :syslog-options (byte 0x03)
+       :facility :log-user})}}))