Barebone version of a Sinatra app to show cronjobs on a timeline.

.rvmrc

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+rvm use ree-1.8.7-head@timeline

README

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+== Description
+
+A barebone Sinatra app to show the cron jobs on a timeline.
+
+Powered by SIMILE Timeline Widget: http://www.simile-widgets.org/wiki/Timeline.
+
+Tested on Ubuntu 10.10, FireFox 3.6.13, using ree-1.8.7-head with gemset:
+
+json_pure (1.4.6)
+rack (1.2.1)
+shotgun (0.8)
+sinatra (1.1.2)
+tilt (1.2.1)
+
+== Version
+
+0.0.1 (Jan 3rd, 2011)
+
+== Installation
+
+Install the required gems and then git clone git://github.com/shanko/misc.git
+
+== Usage
+
+$ shotgun cron_timeline.rb
+
+== ToDo
+
+* Improve the rendering of the timeline
+* RSpec examples
+* Documentation
+
+== Author
+
+Shashank Date <mailto:stdate@gmail.com>
+
+== License
+
+MIT license: http://www.opensource.org/licenses/mit-license.php
+
+
+
+
+

cron_timeline.rb

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+require 'rubygems'
+require 'sinatra'
+require 'json'
+require 'models/parse_cron'
+
+get "/cron" do
+  cron_jobs = ['*/15  *  *  1 * whoami','*/30  *  *  1 * uname' ]
+  hr_window = 2
+  erb :cron, :locals => { :json => to_timeline_hash(cron_jobs,hr_window).to_json } 
+end 
+
+

models/parse_cron.rb

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+require "pp"
+
+def parse_time_element(te,from,to)
+  ret = []
+
+  if te =~ /^\d+$/
+    ret << te.to_i
+  elsif te =~ /^[*]$/
+    ret = (from..to).to_a
+  elsif te =~ /,/
+    te.split(',').each do |e|
+      if e =~ /^\d+$/
+        ret << e.to_i
+      elsif e =~ /-/
+        ret += parse_time_element(e,from,to)
+      else
+        raise "Cannot parse: #{te}"
+      end
+    end
+  elsif te =~ /^(\d+)-(\d+)\/?(\d+)?$/
+    if $3.to_i < 2
+      ret = ($1.to_i..$2.to_i).to_a
+    else
+      step = $3.to_i
+      start = $1.to_i
+      stop = $2.to_i
+      while start < stop do
+        ret << start
+        start += step
+      end
+    end
+  elsif te =~ /^[*]\/(\d+)$/
+    freq = $1.to_i
+    to_limit = (to - from + 1)
+    if freq > 0 && freq < to_limit
+      to_limit.times do |i|
+        m = i * freq
+        break if m >= to_limit
+        ret << m
+      end
+    else
+      raise "Cannot parse: #{te}"
+    end
+  else
+    raise "Cannot parse: #{te}"
+  end
+  ret
+end
+
+def canonize(min, hr, day, month, wday, cmd)
+  cmd_str   = cmd.join(" ")
+  minutes   = parse_time_element(min,   0, 59)
+  hours     = parse_time_element(hr,    0, 23)
+  days      = parse_time_element(day,   1, 31)
+  months    = parse_time_element(month, 1, 12)
+  week_days = parse_time_element(wday,  0,  6)
+  return [minutes, hours, days, months, week_days, cmd_str]
+end
+
+def will_execute_at?(cron_entry,at_time=Time.now)
+  val = true
+  at  = [at_time.min, at_time.hour, at_time.day, at_time.month, at_time.wday]
+
+  cron_entry.each_with_index do |element,i|
+    next if element.class == String
+    found = false
+    element.each{|t| found = (at[i] == t); break if found}
+    unless found
+      val = found
+      break
+    end
+  end
+
+  val
+end
+
+def will_execute_when?(cron_entry,from_time,to_time)
+  times = []
+  return times if from_time > to_time
+  min = 0
+  next_minute = from_time + min * 60
+  while (next_minute <= to_time)
+    times << next_minute if will_execute_at?(cron_entry,next_minute)
+    min += 1
+    next_minute = from_time + min * 60
+  end
+  times
+end
+
+def cron_hash(cron_jobs,hour_window=1)
+  reverse_cron_hash = {}
+  cron_jobs.each do |line|
+    next if (line.strip.size == 0) || (line =~ /^\s*#/)
+    min, hr, day, month, week_day, *cmd = line.strip.split
+
+    begin
+      cron_entry =  canonize(min, hr, day, month, week_day, cmd)
+      # pp cron_entry
+
+      from, to = Time.now, Time.now + (hour_window * 60 * 60)
+      arr = will_execute_when?(cron_entry,from,to)
+
+      arr.each do |time_element|
+        if reverse_cron_hash[time_element.to_s]
+          reverse_cron_hash[time_element.to_s] << cron_entry[-1] unless reverse_cron_hash[time_element.to_s].include?(cron_entry[-1])
+        else
+          reverse_cron_hash[time_element.to_s] = [cron_entry[-1]]
+        end
+      end
+
+    rescue
+      puts "---------------------\n"  + line + ' ' + $!.to_s
+    end
+  end
+  reverse_cron_hash
+end
+
+def to_timeline_hash(cron_jobs,hour_window)
+  chash = cron_hash(cron_jobs,hour_window)
+  events_arr = []
+  chash.each do |key,val|
+     val.each do |cmd|
+       events_arr << {"start" => key, "instant" => true, "title" => cmd, "description" => ""}
+     end
+  end
+
+  event_data = {
+    'dateTimeFormat' => 'Gregorian',
+    'events'         => events_arr 
+  }
+
+  # pp event_data
+
+  event_data
+end
+
+if __FILE__ == $0
+  # min hr day month week-day command
+  cron_jobs = ['*/15  *  *  1 * whoami','*/30  *  *  1 * uname' ]
+  # cron_jobs = `crontab -l`
+  # cron_jobs = File.readlines("cronfile.txt")
+
+  puts
+  pp to_timeline_hash(cron_jobs,2)
+end
+
+
+

public/timeline_ajax/content/history.html

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+<html>
+<head>
+    <title>Dummy Page for Keeping Track of History</title>
+</head>
+<body>
+</body>
+</html>

public/timeline_ajax/scripts/signal.js

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+/*==================================================
+ *  This file is used to detect that all outstanding
+ *  javascript files have been loaded. You can put
+ *  a function reference into SimileAjax_onLoad
+ *  to have it executed once all javascript files
+ *  have loaded.
+ *==================================================
+ */
+(function() {
+    var substring = SimileAjax.urlPrefix + "scripts/signal.js";
+    var heads = document.documentElement.getElementsByTagName("head");
+    for (var h = 0; h < heads.length; h++) {
+        var node = heads[h].firstChild;
+        while (node != null) {
+            if (node.nodeType == 1 && node.tagName.toLowerCase() == "script") {
+                var url = node.src;
+                var i = url.indexOf(substring);
+                if (i >= 0) {
+                    heads[h].removeChild(node); // remove it so we won't hit it again
+
+                    var count = parseInt(url.substr(url.indexOf(substring) + substring.length + 1));
+                    SimileAjax.loadingScriptsCount -= count;
+                    if (SimileAjax.loadingScriptsCount == 0) {
+                        var f = null;
+                        if (typeof SimileAjax_onLoad == "string") {
+                            f = eval(SimileAjax_onLoad);
+                            SimileAjax_onLoad = null;
+                        } else if (typeof SimileAjax_onLoad == "function") {
+                            f = SimileAjax_onLoad;
+                            SimileAjax_onLoad = null;
+                        }
+
+                        if (f != null) {
+                            f();
+                        }
+                    }
+                    return;
+                }
+            }
+            node = node.nextSibling;
+        }
+    }
+})();