logviewer-mode of emacs
近来经常需要查看某些 Log 文件，当用 Emacs 打开这些巨大的 Log 文件的时候，总是需要等待较长的时间，且没有什么语法高亮， 不能让自己感兴趣的区域来吸引眼球。
Google 了一下，发现没有很合适的 log viewer ， 有一个 log4j， 试用了一下，效果不好，还有一个纯粹的 viewer-mode ， 也不太好。 于是自己动手写了一个，主要特色有：
- Log 语法高亮
- 与 VIM 打开 /var/log/messages 时的效果类似。
- 打开大文件时自动分割成若干小文件，并逐片打开和显示这个功能在打开大文件时候比较好用，该状态下，可通过 n 和 p 来在分片中切换 。
- (未完成)Log 级别过滤该功能尚未添加，主要是想可以对 log 进行过滤，比如只显示 ERROR 以上级别的 log 等， 现在对这个功能的需求不大，等以后再加上吧。
代码如下（使用方法参考代码注释）:
;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;; ;; logviewer.el --- Simple log viewer. ;; ;; Copyright (C) 2011, Yang, Ying-chao ;; ;; Author: Yang, Ying-chao <yangyingchao@gmail.com> ;; ;; This file is NOT part of GNU Emacs. ;; ;; This program is free software; you can redistribute it and/or ;; modify it under the terms of the GNU General Public License ;; as published by the Free Software Foundation; either version 2 ;; of the License, or (at your option) any later version. ;; ;; This program is distributed in the hope that it will be useful, ;; but WITHOUT ANY WARRANTY; without even the implied warranty of ;; MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the ;; GNU General Public License for more details. ;; ;; You should have received a copy of the GNU General Public License ;; along with this program; if not, write to the Free Software ;; Foundation, Inc., 59 Temple Place - Suite 330, Boston, MA 02111-1307, USA. ;; ;; Commentary: ;; ;; This is a simple log viewer, with syntax highlight. ;; ;; To use logviewer, you should put logviewer.el into the top of load-path ;; of emacs, the add following lines into your .emacs: ;; (require 'logviewer) ;; ;; When log files are huge, it will try to split huge logs into small ones ;; to speed up loading. In that case, you can press "n" & "p" to go to next ;; part (or previous part) to the log file. You can custom variable ;; logviewer-split-line to proper number to control the size of the slice of ;; huge file. ;; ;; TODO: ;; Add support of log filtering, ie, show logs whos level is higher than ;; some specified one. ;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;
;; Code ;; custom hooks (defvar logviewer-mode-hook nil) ;; default mode map, really simple (defvar logviewer-mode-map (let ((logviewer-mode-map (make-keymap))) (define-key logviewer-mode-map "n" (lambda () (interactive) (logviewer-next-file t))) (define-key logviewer-mode-map "p" (lambda () (interactive) (logviewer-next-file nil))) logviewer-mode-map) "Keymap for PS major mode") (defvar logviewer-indent-width 4) (defvar logviewer-font-lock-keywords `( ;; Date & time. (,(rx line-start (*? not-newline) (+ digit) ":" (+ digit) ":" (+ digit) (? "." (+ digit))) . font-lock-builtin-face) (,(rx symbol-start (group (*? not-newline) (+ digit) ":" (+ digit) ":" (+ digit) (? "." (+ digit))) (1+ space) (group (1+ (or alnum "-" "_" blank))) (? "["(* digit) "]")":") (1 font-lock-builtin-face) (2 font-lock-variable-name-face)) (,(rx symbol-start (group (or "ERROR" "FATAL" "error" "fatal" )) ":" (group (+ (*? not-newline))) line-end) (1 font-lock-warning-face) (2 font-lock-comment-face)) (,(rx symbol-start (group (or "info" "INFO" )) ":" (group (+ (*? not-newline))) line-end) (1 font-lock-function-name-face) (2 font-lock-doc-face)) (,(rx symbol-start (group (or "DEBUG" "debug" )) ":" (group (+ (*? not-newline))) line-end) (1 font-lock-keyword-face) (2 font-lock-string-face)) ) ) (defvar logviewer-mode-syntax-table (make-syntax-table) "Syntax table for Logviewer mode") ;; (modify-syntax-entry ?( "()" logviewer-mode-syntax-table) ;; (modify-syntax-entry ?) ")(" ;; logviewer-mode-syntax-table) (defvar logviewer-imenu-expressions '((nil "^\\(?:[fF]unction\\|Add-Class\\)\\s-+\\([-a-z0-9A-Z_^:.]+\\)[^-a-z0-9A-Z_^:.]" 1)) "alist of regexp identifying the start of logviewer definitions" ) (defvar logviewer-split-line 50000 "Lines when trying to split files.") (defvar Logviewer-current-file nil "Log file viewed by logviewer") (defun logviewer-process-sentinel (process event) "description" (when (memq (process-status process) '(signal exit)) (let* ((exit-status (process-exit-status process)) (command (process-command process)) (source-buffer (process-buffer process)) ) (condition-case err (delete-process process) (error (let ((err-str (format "Error in process sentinel: %s" (error-message-string err)))) (message err-str))))))) ;;;; Overrite function provied by Emacs itself. (defun abort-if-file-too-large (size op-type filename) "If file SIZE larger than `large-file-warning-threshold', allow user to abort. OP-TYPE specifies the file operation being performed (for message to user)." (let* ((re-log-str (rx (or "LOG" "log" "Log"))) (log-cache (expand-file-name "~/.emacs.d/log_cache")) (cur-file nil) (process nil) (filename-base (file-name-sans-extension (file-name-nondirectory filename))) (out-file-prefix (format "%s/%s" log-cache filename-base))) (if (and large-file-warning-threshold size (> size large-file-warning-threshold)) (if (string-match re-log-str filename) ;; This is logfile. (if (y-or-n-p (format "LogFile %s is large (%dMB), really %s? " (file-name-nondirectory filename) (/ size 1048576) op-type)) (if (and (string= op-type "open") (executable-find "split")) (progn (if (file-exists-p log-cache) nil (mkdir log-cache t)) (setq Logviewer-current-file (format "%s000" out-file-prefix)) (message (format "%s*" out-file-prefix)) (call-process-shell-command "rm" nil "*Messages*" nil "-rf" (format "%s*" out-file-prefix)) (setq process (start-process "Split-process" "*Messages*" "split" "--suffix-length=3" "-d" "-l" (format "%s" logviewer-split-line) (expand-file-name filename) out-file-prefix)) (set-process-sentinel process 'logviewer-process-sentinel) (while (not (file-exists-p Logviewer-current-file)) (sleep-for 0.5)) (set-buffer (get-buffer-create filename-base)) (toggle-read-only 0) (erase-buffer) (insert-file-contents Logviewer-current-file nil) (switch-to-buffer filename-base) (toggle-read-only 1) (add-to-list 'recentf-list filename) (logviewer-mode) (error "See this instead") ) nil (error "Aborted") ) (when (not (y-or-n-p (format "YC: File %s is large (%dMB), really %s? " (file-name-nondirectory filename) (/ size 1048576) op-type))) (error "Aborted")) ) ) ))) (defun get-next-file (cc) "Get next file, or previous file. if direc = t, it returns next file, or it returns previous file" (let ((filename-pre nil) (filename-sub nil) (filename Logviewer-current-file) (filename-sub-num 0) (sub-len 0) (new-seq 0) (fmt "") (pre-rx (rx line-start (group (+? not-newline)) (group (+ digit)) line-end))) (if (string-match pre-rx filename) (progn (setq filename-pre (match-string 1 filename)) (setq filename-sub (match-string 2 filename)) (setq sub-len (length filename-sub)) (if cc (setq new-seq (1+ (string-to-number filename-sub))) (setq new-seq (1- (string-to-number filename-sub))) ) (format (format "%%s%%0%dd" sub-len) filename-pre new-seq)) (error "Failed to parse filename")))) (defun logviewer-next-file (dir) "view next/previous file" (let ((next-file nil)) (if (string-match "log_cache" Logviewer-current-file) (progn (setq next-file (get-next-file dir)) (if (file-exists-p next-file) (progn (message (format "Now viewing: %s" next-file)) (toggle-read-only 0) (erase-buffer) (insert-file-contents next-file nil) (setq Logviewer-current-file next-file) (toggle-read-only 1)) (progn (let ((msg nil)) (if dir (setq msg (concat "Tail of log reached. File " next-file " does not exist!" )) (setq msg (concat "Head of log reached. File " next-file " does not exist!" ))) (error msg)) ) )) (error "This is the whole file")))) (defun logviewer-setup-imenu () "Installs logviewer-imenu-expression." (require 'imenu t) ;; imenu doc says these 3 are buffer-local by default (setq imenu-generic-expression logviewer-imenu-expressions) (imenu-add-menubar-index) ) (defun logviewer-mode () "Major mode for editing Logviewer files" (interactive) (kill-all-local-variables) (setq major-mode 'logviewer-mode) (setq mode-name "logviewer") (set-syntax-table logviewer-mode-syntax-table) (use-local-map logviewer-mode-map) (set (make-local-variable 'font-lock-defaults) '(logviewer-font-lock-keywords)) (toggle-read-only t) (if (not Logviewer-current-file) (setq Logviewer-current-file (buffer-file-name))) (run-hooks 'logviewer-mode-hook)) (add-to-list 'auto-mode-alist '("\\.log\\'" . logviewer-mode)) (provide 'logviewer)
