Send Lisp errors to Graylog2 server

graylog2.lisp

(ql:quickload "usocket")
(ql:quickload "cl-json")
(ql:quickload "salza2")
(ql:quickload "babel")
(ql:quickload "local-time")
(ql:quickload "rutils")

(named-readtables:in-readtable rutil:rutils-readtable)

(defvar *hostname* nil)
(defvar *graylog-host* #(127 0 0 1))
(defvar *graylog-port* 12201)

(defun get-hostname ()
  (or *hostname*
      (setf *hostname* (rutil:substr (rutil:read-file "/etc/hostname") 0 -1))))

(defun unix-timestamp ()
  (local-time:timestamp-to-unix (local-time:now)))

(defun graylog (message &key level backtrace file line-no)
  (let (sock)
    (unwind-protect
         (let ((msg (salza2:compress-data
                     (babel:string-to-octets
                      (json:encode-json-to-string #{:version "1.0"
                                                    :facility "lisp"
                                                    :host (get-hostname)
                                                    :|short_message| message
                                                    :|full_message| backtrace
                                                    :timestamp (unix-timestamp)
                                                    :level level
                                                    :file file
                                                    :line line-no
                                                   })
                      :encoding :utf-8)
                     'salza2:zlib-compressor)))
           (setf sock (usocket:socket-connect *graylog-host* *graylog-port*
                                              :protocol :datagram
                                              :element-type '(unsigned-byte 8)))
           (usocket:socket-send sock msg (length msg))))
      (usocket:socket-close sock)))