I been Using EventMachine for quite a while a know and I really found it
great as It Manage show much more me that i didn't have to worry for
anything.But recently I just found this weird issue which i just fail to
understand
Here what is just telling
I have Eventmachine loop Which look like this
EventMachine::run {
EventMachine::add_periodic_timer(10)
do
EventMachine::defer(@operation_block,@callback_block)
end }
here my operation block look like(Code below use of amqp using carrot
gem)
@operation_block = Proc.new {
begin
puts "Initiating the queue"
@carrot ||= Carrot.new(:host => localhost)
@queue ||= @carrot.queue("my_queue")
puts "The Queue is Poping the message"
if @queue.pop
[MY LOGIC HERE]
$input_to_callback = "SUCCESS" ## IF LOGIC GET
EVALUATED WITHOUT ERROR ELSE WILL SET TO FAIL
else
$input_to_callback = "NOTHING TO PROCESSES"
end
rescue
puts e
retry!
end
$input_to_callback
}
Here my callback block look like
@callback_block = Proc.new {|operation_block_output|
if operation_block_output == "SUCCESS"
puts "YAHOOOOOOOOO SUCCESS"
elsif operation_block_output == "NOTHING TO PROCESSES"
puts "BOO Nothing to processes"
else
puts "FAIL ALARM"
end
}
Now Here come the Trouble
The Code Though Work the way it should until something bad happen
Here what i meant
Now suppose I running this Above Code
I have a queue set name "my_queue" or it will create one if it doesn't
exists the queue is initially empty
here the output that I get on console
Initiating the queue
The Queue is Poping the Message
BOO Nothing to processes
As I message built the output Change in console accordingly based
Now the trouble
If I momentarily shutdown my AMQP server Here the output(to show what
i meant)
Initiating the queue
Broken Pipe => Error That Caught in
begin rescue block in operation block
Now Start AMQP Server
The Code just never seem move ahead from line where it currently got
error
that means I never Seem to print the line
The Queue is Poping the message
not only the current defer for which is retry happened but also the
new defer operation block that get initiated after the Timer time just
elapsed
i.e means of the subsequent call to operation block
never seem to move ahead and do processing and always print the
following
output only
Initiating the queue
Just never seem to move ahead(stuck) and do Processing that it meant
to i.e fetch the message from the queue do the processing accordingly
and all the other stuff(as the AMQP server is running now)
Thanks
···
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