Monitoring thread variables in ruby - ruby

Question

I'm building a task runner where each task is built from a number of commands:
def run
begin
#Validating task params
set_progress "Validating params", "Validating params: #{#params}"
validate_params
#task_info["steps"].each do |step|
#log.info "Running command: #{step["description"]}"
set_progress step["description"]
command = Command.factory #params, step, #signature, #log
timeout = General.in_seconds step["timeout"]
command_res = Timeout.timeout(timeout) do
command.execute
end
end
set_progress "Completed"
rescue Exception => exception
#log.error exception.message + "\nBACK TRACE:\n" + exception.backtrace.join("\n")
set_progress #progress, "Failed, check logs. exception: #{exception.message}"
end
end
Now the command is ran by "command.execute", and there is a field inside the command class which is called "current_status" which i would like to monitor each X seconds and check the command status in order to update the user about the command status, how can i do it ? i probably need to run the command in a separate thread and then monitor it, but how can i monitor it ?

Answer 1

a quick and dirty methodology which might contain syntax errors :P
class JobManager
def initialize
#threads =[]
end
def registered_jobs
#registered_jobs ||= [Job1.new, Job2.new]
end
def start_jobs
registered_jobs.each {|j| #threads << Thread.new { j.run } }
end
def statuses?
registered_jobs.collect {|j| j.status? }
end
end
Usage:
manager = JobManager.new
manager.start_jobs
# elsewhere
manager.statuses? # returns [Job1.status?, Job2.status?]
This is the sort of idiom I'd use in my code. It's important to be aware that the status variables are subject to race conditions if they are not properly guarded against concurrent modification and access.