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require File.join(File.dirname(__FILE__),'error')
DEFAULT_TASK_MAX_DURATION = 36000
module OpenTox
# Class for handling asynchronous tasks
class Task
attr_accessor :pid, :observer_pid
def self.create service_uri, params={}
task = Task.new RestClient.post(service_uri,params).chomp
pid = fork do
begin
result_uri = yield
if URI.accessible?(result_uri)
task.completed result_uri
else
raise "#{result_uri} is not a valid URI"
end
rescue
# TODO add service URI to Kernel.raise
# serialize error and send to task service
#task.error $!
task.error $!
raise
end
end
Process.detach(pid)
task.pid = pid
# watch if task has been cancelled
observer_pid = fork do
task.wait_for_completion
begin
Process.kill(9,task.pid) if task.cancelled?
rescue
$logger.warn "Could not kill process of task #{task.uri}, pid: #{task.pid}"
end
end
Process.detach(observer_pid)
task.observer_pid = observer_pid
task
end
def kill
Process.kill(9,@pid)
Process.kill(9,@observer_pid)
rescue # no need to raise an aexeption if processes are not running
end
def description
metadata[RDF::DC.description]
end
def cancel
kill
RestClient.put(File.join(@uri,'Cancelled'),{})
end
def completed(uri)
#TODO: subjectid?
#TODO: error code
raise "\"#{uri}\" does not exist." unless URI.accessible? uri
RestClient.put(File.join(@uri,'Completed'),{:resultURI => uri})
end
def error error
$logger.error self if $logger
report = ErrorReport.create(error,"http://localhost")
RestClient.put(File.join(@uri,'Error'),{:errorReport => report})
kill
end
# waits for a task, unless time exceeds or state is no longer running
# @param [optional,Numeric] dur seconds pausing before checking again for completion
def wait_for_completion(dur=0.3)
due_to_time = Time.new + DEFAULT_TASK_MAX_DURATION
while running?
sleep dur
raise "max wait time exceeded ("+DEFAULT_TASK_MAX_DURATION.to_s+"sec), task: '"+@uri.to_s+"'" if (Time.new > due_to_time)
end
end
end
# get only header for ststus requests
def running?
RestClient.head(@uri){ |response, request, result| result.code.to_i == 202 }
end
def cancelled?
RestClient.head(@uri){ |response, request, result| result.code.to_i == 503 }
end
def completed?
RestClient.head(@uri){ |response, request, result| result.code.to_i == 200 }
end
def error?
RestClient.head(@uri){ |response, request, result| result.code.to_i == 500 }
end
def method_missing(method,*args)
method = method.to_s
begin
case method
when /=/
res = RestClient.put(File.join(@uri,method.sub(/=/,'')),{})
super unless res.code == 200
#when /\?/
#return hasStatus == method.sub(/\?/,'').capitalize
else
response = metadata[RDF::OT[method]].to_s
response = metadata[RDF::OT1[method]].to_s #if response.empty? # API 1.1 compatibility
if response.empty?
$logger.error "No #{method} metadata for #{@uri} "
raise "No #{method} metadata for #{@uri} "
end
return response
end
rescue
$logger.error "Unknown #{self.class} method #{method}"
#super
end
end
#TODO: subtasks
end
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