a helper for creating list of 'HH:MM' for the `at` option of `Clockwork.every` with alignment and hour ranges

README.md

Use this in your clock.rb file:

require 'clockwork'

include ClockHelper

module Clockwork
  # ...
  every 1.day, "do_something", at: steps(every: 3.hours, aligned_at: '01:32') do
    # do things ...
  end
  # ...
end

clock_helper.rb

module ClockHelper
  # creates a list of 'HH:MM' for the `at:` option of `Clockwork.every`
  #
  # steps(every: 4.hours, aligned_at: '17:03')
  # #=> ["01:03", "05:03", "09:03", "13:03", "17:03", "21:03"]
  # steps(every: 2.hours, between: 12.hours..17.hours, aligned_at: '17:03')
  # #=> ["13:03", "15:03"]
  def steps(every:, aligned_at: '00:00', between: 0.hours...24.hours)
    beginning_of_day = aligned_at.to_time.beginning_of_day
    step_offset = (aligned_at.to_time.to_i + aligned_at.to_time.utc_offset) % every
    between.step(every).
      map { |step_in_between| (beginning_of_day + step_in_between + step_offset) }.
      select { |t| ((t.to_i + aligned_at.to_time.utc_offset) % 24.hours).in?(between) }.
      map { |t| t.strftime("%H:%M") }
  end
end

clock_helper_spec.rb

require 'rails_helper'

describe ClockHelper do
  subject { Class.new { include ClockHelper }.new }

  describe "#steps" do
    it "should align times throughout the day" do
      expect(subject.steps(every: 4.hours, aligned_at: "17:03")).
        to eq ["01:03", "05:03", "09:03", "13:03", "17:03", "21:03"]
    end

    context "with specific time span" do
      it "should also align times" do
        expect(subject.steps(every: 2.hours, between: 16.hours..20.hours, aligned_at: "17:03")).
          to eq ["17:03", "19:03"]
      end

      context "when time is outside of the span" do
        it "should also align times" do
          expect(subject.steps(every: 2.hours, between: 12.hours..17.hours, aligned_at: "17:03")).
            to eq ["13:03", "15:03"]
        end
      end

      context "when close to the end of day" do
        it "should also align times" do
          expect(subject.steps(every: 2.hours, between: 20.hours...24.hours, aligned_at: "17:03")).
            to eq ["21:03", "23:03"]
        end
      end
    end

    context "with < 1h intervals" do
      it do
        expect(subject.steps(every: 15.minutes, between: 12.hours...13.5.hours, aligned_at: "17:03")).
          to eq ["12:03", "12:18", "12:33", "12:48", "13:03", "13:18"]
      end
    end
  end
end