/
worker.rb
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/
worker.rb
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#--
# Copyright (c) 2005-2011, John Mettraux, jmettraux@gmail.com
#
# Permission is hereby granted, free of charge, to any person obtaining a copy
# of this software and associated documentation files (the "Software"), to deal
# in the Software without restriction, including without limitation the rights
# to use, copy, modify, merge, publish, distribute, sublicense, and/or sell
# copies of the Software, and to permit persons to whom the Software is
# furnished to do so, subject to the following conditions:
#
# The above copyright notice and this permission notice shall be included in
# all copies or substantial portions of the Software.
#
# THE SOFTWARE IS PROVIDED "AS IS", WITHOUT WARRANTY OF ANY KIND, EXPRESS OR
# IMPLIED, INCLUDING BUT NOT LIMITED TO THE WARRANTIES OF MERCHANTABILITY,
# FITNESS FOR A PARTICULAR PURPOSE AND NONINFRINGEMENT. IN NO EVENT SHALL THE
# AUTHORS OR COPYRIGHT HOLDERS BE LIABLE FOR ANY CLAIM, DAMAGES OR OTHER
# LIABILITY, WHETHER IN AN ACTION OF CONTRACT, TORT OR OTHERWISE, ARISING FROM,
# OUT OF OR IN CONNECTION WITH THE SOFTWARE OR THE USE OR OTHER DEALINGS IN
# THE SOFTWARE.
#
# Made in Japan.
#++
require 'ruote/fei'
module Ruote
#
# Workers fetch 'msgs' and 'schedules' from the storage and process them.
#
# Read more at http://ruote.rubyforge.org/configuration.html
#
class Worker
EXP_ACTIONS = %w[ reply cancel fail receive dispatched ]
# 'apply' is comprised in 'launch'
# 'receive' is a ParticipantExpression alias for 'reply'
PROC_ACTIONS = %w[ cancel_process kill_process ]
DISP_ACTIONS = %w[ dispatch dispatch_cancel ]
attr_reader :storage
attr_reader :context
attr_reader :run_thread
attr_reader :running
def initialize(storage)
@subscribers = []
# must be ready before the storage is created
# services like Logger to subscribe to the worker
@storage = storage
@context = Ruote::Context.new(storage, self)
@last_time = Time.at(0.0).utc # 1970...
@running = true
@run_thread = nil
@msgs = []
@sleep_time = 0.000
end
# Runs the worker in the current thread. See #run_in_thread for running
# in a dedicated thread.
#
def run
step while @running
end
# Triggers the run method of the worker in a dedicated thread.
#
def run_in_thread
Thread.abort_on_exception = true
# TODO : remove me at some point
@running = true
@run_thread = Thread.new { run }
end
# Joins the run thread of this worker (if there is no such thread, this
# method will return immediately, without any effect).
#
def join
@run_thread.join if @run_thread
end
def subscribe(actions, subscriber)
@subscribers << [ actions, subscriber ]
end
def shutdown
@running = false
return unless @run_thread
begin
@run_thread.join
rescue Exception => e
end
end
# Returns true if the engine system is inactive, ie if all the process
# instances are terminated or are stuck in an error.
#
# NOTE : for now, if a branch of a process is in error while another is
# still running, this method will consider the process instance inactive
# (and it will return true if all the processes are considered inactive).
#
def inactive?
# the cheaper tests first
return false if @msgs.size > 0
return false unless @context.storage.empty?('schedules')
return false unless @context.storage.empty?('msgs')
wfids = @context.storage.get_many('expressions').collect { |exp|
exp['fei']['wfid']
}
error_wfids = @context.storage.get_many('errors').collect { |err|
err['fei']['wfid']
}
(wfids - error_wfids == [])
end
protected
def step
now = Time.now.utc
delta = now - @last_time
if delta >= 0.8
#
# at most once per second, deal with 'ats' and 'crons'
@last_time = now
@storage.get_schedules(delta, now).each { |sche| trigger(sche) }
end
# msgs
@msgs = @storage.get_msgs if @msgs.empty?
processed = 0
collisions = 0
while msg = @msgs.shift
r = process(msg)
if r != false
processed += 1
else
collisions += 1
end
if collisions > 2
@msgs = @msgs[(@msgs.size / 2)..-1] || []
end
#@msgs.concat(@storage.get_local_msgs)
#print r == false ? '*' : '.'
break if Time.now.utc - @last_time >= 0.8
end
#p processed
if processed == 0
@sleep_time += 0.001
@sleep_time = 0.499 if @sleep_time > 0.499
sleep(@sleep_time)
else
@sleep_time = 0.000
end
end
def trigger(schedule)
msg = Ruote.fulldup(schedule['msg'])
return false unless @storage.reserve(schedule)
@storage.put_msg(msg.delete('action'), msg)
true
end
def process(msg)
return false unless @storage.reserve(msg)
begin
action = msg['action']
if msg['tree']
#
# warning here, it could be a reply, with a 'tree' key...
launch(msg)
elsif EXP_ACTIONS.include?(action)
Ruote::Exp::FlowExpression.do_action(@context, msg)
elsif DISP_ACTIONS.include?(action)
@context.dispatch_pool.handle(msg)
elsif PROC_ACTIONS.include?(action)
self.send(action, msg)
#else
# msg got deleted, might still be interesting for a subscriber
end
notify(msg)
rescue Exception => exception
@context.error_handler.msg_handle(msg, exception)
end
true
end
def notify(msg)
@subscribers.each do |actions, subscriber|
if actions == :all || actions.include?(msg['action'])
subscriber.notify(msg)
end
end
end
# Works for both the 'launch' and the 'apply' msgs.
#
def launch(msg)
tree = msg['tree']
variables = msg['variables']
exp_class = @context.expmap.expression_class(tree.first)
# msg['wfid'] only : it's a launch
# msg['fei'] : it's a sub launch (a supplant ?)
exp_hash = {
'fei' => msg['fei'] || {
'engine_id' => @context.engine_id,
'wfid' => msg['wfid'],
'subid' => Ruote.generate_subid(msg),
'expid' => '0' },
'parent_id' => msg['parent_id'],
'original_tree' => tree,
'variables' => variables,
'applied_workitem' => msg['workitem'],
'forgotten' => msg['forgotten']
}
if not exp_class
exp_class = Ruote::Exp::RefExpression
elsif is_launch?(msg, exp_class)
def_name, tree = Ruote::Exp::DefineExpression.reorganize(tree)
variables[def_name] = [ '0', tree ] if def_name
exp_class = Ruote::Exp::SequenceExpression
end
exp = exp_class.new(@context, exp_hash.merge!('original_tree' => tree))
exp.initial_persist
exp.do_apply
end
def is_launch?(msg, exp_class)
return false if exp_class != Ruote::Exp::DefineExpression
return true if msg['action'] == 'launch'
(msg['trigger'] == 'on_re_apply')
end
def cancel_process(msg)
root = @storage.find_root_expression(msg['wfid'])
return unless root
flavour = (msg['action'] == 'kill_process') ? 'kill' : nil
@storage.put_msg(
'cancel',
'fei' => root['fei'],
'wfid' => msg['wfid'], # indicates this was triggered by cancel_process
'flavour' => flavour)
end
alias :kill_process :cancel_process
end
end