elog

What is elog

elog is a simple logging library for elisp. It is extended from logito

How to use elog

1. require the file

   (require 'elog)
       

2. use `elog-open-log’ macro to generate your own logging function.

   (elog-open-log TYPE IDENT &rest init-args)
       

   This macro generate two functions: the `elog-IDENT-log’ for logging job and the `elog-IDENT-close-log’ for cleanning job.

   `TYPE’ specify which kind of elog-object is used. Now, elog support four types of elog-object:

   message

   use `message’ function to do the logging job.

   buffer

   log item will be recoreded in a specify buffer.

   file

   log item will be recoreded in a specify file.

   syslog

   log item will be send to a syslogd server.

   `init-args’ is used to initialize the elog-object.

   • the base elog-object

     :serverity

     specify the logging level. The default value is `elog-info’

     :fmt

     specify the logging format string. There are some %-sequences has a special meaning in it. %I means the `IDENT’ argument %T means current time %L means level %M means message

   • the elog-buffer-object

     :buffer

     It specify which buffer is used to record the logging item.

   • the elog-file-object

     :file

     It specify which file is used to record the logging item.

   • the elog-syslog-object

     :host

     It specify the syslogd server host

     :port

     It specify the syslogd service port

     :facility

     It specify the facility

3. use `IDENT-log’ function to do the logging job.

   (IDENT-log LEVEL FORMAT-STRING &rest OBJECTS)

4. use `IDENT-close-log’ function to do the cleanning job if you wish.

   (IDENT-close-log)

5. use `IDENT-set-log-serverity’ function to change the logging serverity

   (IDENT-set-log-serverity NEW-SERVERITY)

6. use `IDENT-log-serverity’ function to get the current logging serverity

   (IDENT-log-serverity)

Examples

use message function to display log

(elog-open-log message "MSG" :prelog-functions (list (lambda (log)
                                                       (message "start to log at %s" (current-time-string))))
                             :postlog-functions (list (lambda (log)
                                                       (message "log done at %s" (current-time-string)))))

(MSG-log elog-error "%s-%d" "hello" 123)

record log to a buffer

(elog-open-log buffer "BUF" :buffer "elog")

(BUF-log elog-error "%s-%d" "hello" 123)

(BUF-close-log)

record log to a file

(defun elog-get-log-name ()
  (format "/tmp/%s/elog.log" (format-time-string "%Y%m/%d")))
(elog-open-log file "FILE" :file 'elog-get-log-name
                           :modes 700
                           :max-size 10
                           :old-dir "/tmp/elog/"
                           :compress-command "gzip %L")
(FILE-log-serverity)
(FILE-set-log-serverity elog-emerg)

 (FILE-log elog-error "%s-%d" "hello" 123)

record log to syslog

(elog-open-log syslog "SYSLOG" :host "10.8.208.121" :port 514 :facility elog-local7)

(SYSLOG-log elog-error "%s-%d" "hello" 123)

(SYSLOG-close-log)

How to extend elog

Elog is extensible. You just need to define a new subclass of elog-object three method:

elog-should-log-p

this function is used to check if the log item should be recorded

elog-insert-log

this function is used to do the actual logging job

elog-close-log

this function is used to do the cleanning job.