Naughty log watcher

From awesome

Here's a log watcher implementation in pure Lua. It will show a naughty popup each time something changes in one of the predefined log files.

1. You need to make and install luainotify from here:

http://www3.telus.net/taj_khattra/luainotify.html

2. Require the module:

require("inotify")

3. Set some config variables (make sure the files are readable to you):

config.logs = {
  mpd       = { file = "/home/koniu/.mpd/mpd.log", },
  aptitude  = { file = "/var/log/aptitude", },
  syslog    = { file = "/var/log/syslog",
                ignore = { "Changing fan level" },
  },
  awesome   = { file = "/home/koniu/log/awesome",
                ignore = {
                  "/var/lib/dpkg", -- aptwidget failure when aptitude running
                  "wicd", "wired profiles found", -- wicd junk
                  "seek to:", "Close unzip stream", -- gmpc junk
                  "^nolog"
                },
  },
}
config.logs_quiet = nil
config.logs_interval = 1

4. Add the log watcher functions to your rc:

function log_watch()
  local events, nread, errno, errstr = inot:nbread()
  if events then
    for i, event in ipairs(events) do
      for logname, log in pairs(config.logs) do
        if event.wd == log.wd then log_changed(logname) end
      end
    end
  end
end

function log_changed(logname)
  local log = config.logs[logname]

  -- read log file
  local f = io.open(log.file)
  local l = f:read("*a")
  f:close()

  -- first read just set length
  if not log.len then
    log.len = #l

  -- if updated
  else
    local diff = l:sub(log.len +1, #l-1)

    -- check if ignored
    local ignored = false
    for i, phr in ipairs(log.ignore or {}) do
    if diff:find(phr) then ignored = true; break end
    end

    -- display log updates
    if not (ignored or config.logs_quiet) then
      naughty.notify{
        title = '<span color="white">' .. logname .. "</span>: " .. log.file,
        text = awful.util.escape(diff),
        hover_timeout = 0.2, timeout = 0,
      }
    end

    -- set last length
    log.len = #l
  end
end

local errno, errstr
inot, errno, errstr = inotify.init(true)
for logname, log in pairs(config.logs) do
  log_changed(logname)
  log.wd, errno, errstr = inot:add_watch(log.file, { "IN_MODIFY" })
end

awful.hooks.timer.register(config.logs_interval, log_watch)

That's it. Screenshots: http://omploader.org/vMW9jNw, http://omploader.org/vMW9reQ