Class: Herald

Inherits:
Object
  • Object
show all
Defined in:
lib/herald.rb,
lib/herald/item.rb,
lib/herald/version.rb,
lib/herald/watcher.rb,
lib/herald/notifier.rb,
lib/herald/watchers/rss.rb,
lib/herald/notifiers/ping.rb,
lib/herald/notifiers/post.rb,
lib/herald/notifiers/growl.rb,
lib/herald/notifiers/stdout.rb,
lib/herald/watchers/twitter.rb,
lib/herald/watchers/website.rb,
lib/herald/notifiers/callback.rb

Defined Under Namespace

Classes: Item, Watcher

Constant Summary collapse

VERSION = 
"0.2"
@@heralds = 
[]

Instance Attribute Summary collapse

Class Method Summary collapse

Instance Method Summary collapse

Constructor Details

#initialize(&block) ⇒ Herald

instance methods:



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# File 'lib/herald.rb', line 80

def initialize(&block)
  @watchers = []
  @keep_alive = true
  if block_given?
    instance_eval(&block)
  end
  @@heralds << self
  self
end

Instance Attribute Details

#keep_alive ⇒ Object

Returns the value of attribute keep_alive.



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# File 'lib/herald.rb', line 12

def keep_alive
  @keep_alive
end

#subprocess ⇒ Object

Returns the value of attribute subprocess.



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# File 'lib/herald.rb', line 12

def subprocess
  @subprocess
end

#watchers ⇒ Object

Returns the value of attribute watchers.



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# File 'lib/herald.rb', line 12

def watchers
  @watchers
end

Class Method Details

.alive? ⇒ Boolean

Returns:

  • (Boolean) 


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# File 'lib/herald.rb', line 68

def self.alive?
  @@heralds.any? { |h| h.alive? }
end

.clear ⇒ Object

stop all heralds, and remove them from list of herald instances. mostly useful for clearing @@heralds when testing



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# File 'lib/herald.rb', line 56

def self.clear
  stop()
  @@heralds.clear
  true
end

.demonize! ⇒ Object

just walk away, leaving whatever strays to themselves



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# File 'lib/herald.rb', line 63

def self.demonize!
  @@heralds.clear
  true
end

.heralds ⇒ Object 



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# File 'lib/herald.rb', line 72

def self.heralds
  @@heralds
end

.once(&block) ⇒ Object 



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# File 'lib/herald.rb', line 18

def self.once(&block)
  herald = new()
  herald.keep_alive = false
  herald.send(:instance_eval, &block)
  herald.start
end

.start ⇒ Object

batch methods



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# File 'lib/herald.rb', line 37

def self.start
  return false if @@heralds.empty?
  @@heralds.each do |herald|
    herald.start
  end
  true
end

.stop ⇒ Object 



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# File 'lib/herald.rb', line 45

def self.stop
  return false unless Herald.alive?
  @@heralds.each do |herald|
    herald.stop
  end
  true
end

.watch(&block) ⇒ Object 



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# File 'lib/herald.rb', line 14

def self.watch(&block)
  new(&block).start
end

.watch_rss(options = {}, &block) ⇒ Object 



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# File 'lib/herald.rb', line 29

def self.watch_rss(options = {}, &block)
  watch() { check(:rss, options, &block) }
end

.watch_twitter(&block) ⇒ Object

shorthand methods



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# File 'lib/herald.rb', line 26

def self.watch_twitter(&block)
  watch() { check(:twitter, &block) }
end

.watch_website(options = {}, &block) ⇒ Object 



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# File 'lib/herald.rb', line 32

def self.watch_website(options = {}, &block)
  watch() { check(:website, options, &block) }
end

Instance Method Details

#_for(*keywords) ⇒ Object

send keywords to Watchers



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# File 'lib/herald.rb', line 98

def _for(*keywords)
  @watchers.each do |watcher|
    watcher._for(*keywords)
  end
  self
end

#action(type = nil, options = {}, &block) ⇒ Object

send instructions to Watchers



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# File 'lib/herald.rb', line 106

def action(type = nil, options = {}, &block)
  @watchers.each do |watcher|
    watcher.action(type, options, &block)
  end
  self
end

#alive? ⇒ Boolean

Returns:

  • (Boolean) 


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# File 'lib/herald.rb', line 179

def alive?
  !!@subprocess
end

#check(type, options = {}, &block) ⇒ Object

create a new Watcher



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# File 'lib/herald.rb', line 91

def check(type, options = {}, &block)
  options[:keep_alive] ||= @keep_alive
  @watchers << Herald::Watcher.new(type, options, &block)
  self
end

#every(time) ⇒ Object

send sleep time to Watchers



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# File 'lib/herald.rb', line 114

def every(time)
  @watchers.each do |watcher|
    watcher.every(time)
  end
  self
end

#start ⇒ Object

start Watchers



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# File 'lib/herald.rb', line 122

def start
  if @watchers.empty?
    raise "No watchers assigned"
  end
  # if herald is already running, first stop
  stop() if alive?
  # start watching as a @subprocess
  @subprocess = fork {
    @watchers.each do |watcher|
      watcher.start
    end
    # all watchers do their tasks in a new thread.
    # join all thread in this @subprocess
    Thread.list.each do |thread| 
      thread.join unless thread == Thread.main
    end
  }
  # if herald process is persistant
  if @keep_alive
    Process.detach(@subprocess)
  else
    begin
      # wait before the end of this script
      # for all watchers to finish their jobs
      Process.waitpid(@subprocess)
    # if @subprocess PID does not exist, it will
    # be due to an error in the subprocess
    # which has terminated it and waitpid()
    # will throw an exception
    rescue Errno::ECHILD => e
      # do nothing
    end
    @subprocess = nil # signal unalive state
  end
  self # return instance object
end

#stop ⇒ Object Also known as: end, kill

is there a gentler way of doing it? or have watchers do cleanup tasks on exit? look at GOD



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# File 'lib/herald.rb', line 162

def stop
  if @subprocess
    begin
      Process.kill("TERM", @subprocess)
    # if @subprocess PID does not exist, 
    # this will be due to an error in the subprocess
    # which has terminated it
    rescue Errno::ESRCH => e
      # do nothing
    end
  end
  @subprocess = nil
  self
end