contrib/statusd/statusd_ticker.lua

   1 -- Authors: Matus Telgarsky <mtelgars@andrew.cmu.edu>
   2 -- License: Unknown
   3 -- Last Changed: Unknown
   4 --
   5 -- little ticker boondoggle
   6 --
   7 -- Selects amongst a set of specified commands and scrolls them not only line by line
   8 --  but also within each line.  Waits and marks ends of lines, beginning of command.
   9 --  Should work great with an rss reader though I didn't care to try.
  10 --
  11 -- Author: Matus Telgarsky < mtelgars at andrew dot cmu dot edu >
  12 --
  13 -- I couldn't sleep and felt like learning lua.
  14 --
  15 --
  16
  17 local settings = {
  18     timer = nil,
  19     commands = {
  20         'printf "hello world"',
  21         'fortune',
  22         'df --si',
  23     },
  24     random = true,
  25     line_len = 50,
  26     step = 2,
  27     new = {
  28         hint = "critical",
  29         interval = 1 * 1000,
  30     },
  31     line = {
  32         hint = "important",
  33         interval = 1 * 1000,
  34     },
  35     scroll = {
  36         hint = "normal",
  37         interval = 0.375 * 1000,
  38     },
  39     update_fun = nil, --forward decl hack
  40 }
  41
  42 local message = {
  43     fd = nil,
  44     s = nil,
  45     len = nil,
  46     pos = nil,
  47 }
  48
  49 local function ticker_timer(style)
  50     statusd.inform("ticker_hint", settings[style].hint)
  51     settings.timer:set(settings[style].interval, settings.update_fun)
  52 end
  53
  54 local function ticker_line_init()
  55     message.len = string.len(message.s)
  56     message.pos = 0
  57 end
  58
  59 local function ticker_single()
  60     return settings.commands[1]
  61 end
  62
  63 local function ticker_random()
  64     --don't do same twice, uniformly distribute chances across others
  65     local newpos = math.random(1, settings.commands.count-1)
  66     if newpos >= settings.commands.pos then
  67         newpos = newpos + 1
  68     end
  69
  70     settings.commands.pos = newpos
  71     return settings.commands[settings.commands.pos]
  72 end
  73
  74 local function ticker_rotate()
  75     local c = settings.commands[settings.commands.pos]
  76
  77     if settings.commands.pos == settings.commands.count then
  78         settings.commands.pos = 1
  79     else
  80         settings.commands.pos = settings.commands.pos + 1
  81     end
  82
  83     return c
  84 end
  85
  86 local function ticker_update()
  87     if message.fd == nil then
  88         message.fd = io.popen(settings.commands.get(), 'r')
  89         message.s = message.fd:read()
  90         if message.s then --XXX this is a bug workaround!
  91             ticker_line_init()
  92         end
  93         ticker_timer('new')
  94     elseif message.s == nil then
  95         message.s = message.fd:read()
  96         if message.s == nil then
  97             message.fd:close()
  98             message.fd = nil
  99         else
 100             ticker_line_init()
 101         end
 102         ticker_timer('line')
 103     elseif message.pos + settings.line_len >= message.len then
 104         message.s = nil --hang out at the end of a line
 105         ticker_timer('line')
 106     else
 107         message.pos = message.pos + settings.step
 108         ticker_timer('scroll')
 109     end
 110
 111     if message.s ~= nil then
 112         statusd.inform("ticker",
 113             string.sub(message.s, message.pos, message.pos + settings.line_len))
 114     end
 115 end
 116
 117 if statusd ~= nil then
 118     settings.timer = statusd.create_timer()
 119     statusd.inform("ticker_template", string.rep('x', settings.line_len))
 120
 121     settings.update_fun = ticker_update
 122     settings.commands.count = #(settings.commands)
 123     if settings.commands.count == 1 then
 124         settings.commands.get = ticker_single
 125     elseif settings.random then
 126         settings.commands.pos = 1
 127         settings.commands.get = ticker_random
 128     else
 129         settings.commands.pos = 1
 130         settings.commands.get = ticker_rotate
 131     end
 132
 133     ticker_update()
 134 end