EventMachineAlignedPeriodic

home :: https://github.com/jf647/EventMachineAlignedPeriodic

EventMachine helper to call a block on a periodic schedule with clock alignment.

EventMachineAlignedPeriodic helps to kick off a block of code on a periodic schedule aligned with a time period. Rather than have something starting at 2 seconds, 17 seconds, 32 seconds and so on you can have it consistently launch at 0, 15, 30.

require 'eventmachine'
require 'eventmachine_alignedperiodic'
require 'logger'

log = Logger.new(STDOUT)
log.level = Logger::DEBUG

periodic = EventMachine::AlignedPeriodic.new(interval, proc {
      |partial| do_something(partial)
}, offset, log)

def do_something(partial)
    puts "Yay! I just did something"
    if partial
        puts "... but only partially"
    end
end

EM.run {
    periodic.start
    puts "next event is at #{periodic.nextevent}"
    periodic.poke
    periodic.stop
}

Assuming that interval was 900 (15 minutes) and offset was 30, do_something will be called at the next aligned 15 minute interval. So if you started your program at 10:07:06, it would be called at 10:15:30, then at 10:30:30, 10:45:30 and so on.

Clock resolution and EventMachine latency means that the proc is usually kicked off tens or hundreds of microseconds after the interval.

The first time the proc is called and the last time (when the EventMachine loop shuts down) the partial flag will be true. Every other time it will be false.

The MIT License (MIT)

Copyright (c) 2012, 2013 James FitzGibbon james@nadt.net

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.

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