From 989106dcb128e32fe6c035a6434087508e2c639e Mon Sep 17 00:00:00 2001
From: Nick Elser <nick.elser@gmail.com>
Date: Wed, 6 May 2015 23:23:45 -0700
Subject: [PATCH] version 0.1.1

---
 CHANGELOG.md           |  5 +++++
 README.md              | 20 +++++++++++++++++---
 lib/zhong/at.rb        | 17 +++++++++++++++++
 lib/zhong/job.rb       |  2 +-
 lib/zhong/scheduler.rb | 33 +++++++++++++++++++++++++++++----
 lib/zhong/version.rb   |  2 +-
 6 files changed, 70 insertions(+), 9 deletions(-)

diff --git a/CHANGELOG.md b/CHANGELOG.md
index ec92866..6944dd4 100644
--- a/CHANGELOG.md
+++ b/CHANGELOG.md
@@ -1,3 +1,8 @@
+## 0.1.1
+
+- Handle multiple ats (at: ["mon 8:00, tues 9:30"]).
+- Job callbacks (:before_tick, :after_tick, etc).
+
 ## 0.1.0
 
 - First release.
diff --git a/README.md b/README.md
index 2439bc4..75610df 100644
--- a/README.md
+++ b/README.md
@@ -1,6 +1,8 @@
 # Zhong
 
-Useful, reliable distributed cron.
+Useful, reliable distributed cron. Tired of your cron-like scheduler running key jobs twice? Would you like to be able to run your cron server on multiple machines and have it "just work"? Have we got the gem for you.
+
+Zhong uses Redis to acquire exclusive locks on jobs, as well as recording when they last ran. This means that you can rest easy at night, knowing that your customers are getting their monthly Goat Fancy magazine subscriptions and you are rolling around in your piles of money without a care in the world.
 
 # Installation
 
@@ -18,13 +20,25 @@ r = Redis.new
 Zhong.schedule(redis: r) do |s|
   s.category "stuff" do
     s.every(5.seconds, "foo") { puts "foo" }
-    s.every(1.week, "baz", at: "mon 22:45") { puts "baz" }
+    s.every(1.week, "baz", at: ["mon 22:45", "wed 23:13"]) { puts "baz" }
   end
 
   s.category "clutter" do
-    s.every(1.second, "compute", if: -> (t) { rand < 0.5 }) { puts "something happened" }
+    s.every(1.second, "compute", if: -> (t) { t.wday == 3 && rand < 0.5 }) { puts "something happened on wednesday" }
+  end
+
+  # note: callbacks that return nil or false will cause event to not run
+  s.on(:before_tick) do
+    puts "ding"
+    true
+  end
+
+  s.on(:after_tick) do
+    puts "dong"
+    true
   end
 end
+
 ```
 
 ## TODO
diff --git a/lib/zhong/at.rb b/lib/zhong/at.rb
index 43ff4c1..8309ea7 100644
--- a/lib/zhong/at.rb
+++ b/lib/zhong/at.rb
@@ -43,6 +43,11 @@ def next_at(time = Time.now)
     def self.parse(at, grace: 0)
       return unless at
 
+      # TODO: refactor this mess
+      if at.respond_to?(:each)
+        return MultiAt.new(at.map { |a| parse(a, grace: grace) })
+      end
+
       case at
       when /\A([[:alpha:]]+)\s+(.*)\z/
         wday = WDAYS[$1]
@@ -67,4 +72,16 @@ def self.parse(at, grace: 0)
       throw FailedToParse, at
     end
   end
+
+  class MultiAt
+    attr_accessor :ats
+
+    def initialize(ats = [])
+      @ats = ats
+    end
+
+    def next_at(time = Time.now)
+      ats.map { |at| at.next_at(time) }.min
+    end
+  end
 end
diff --git a/lib/zhong/job.rb b/lib/zhong/job.rb
index 08e904b..1bdd11b 100644
--- a/lib/zhong/job.rb
+++ b/lib/zhong/job.rb
@@ -95,7 +95,7 @@ def to_s
 
     def next_at
       every_time = @every.next_at(@last_ran) if @last_ran && @every
-      at_time = @at.next_at(time) if @at
+      at_time = @at.next_at(Time.now) if @at
       [every_time, at_time, Time.now].compact.max || "now"
     end
 
diff --git a/lib/zhong/scheduler.rb b/lib/zhong/scheduler.rb
index 6c06495..3581df8 100644
--- a/lib/zhong/scheduler.rb
+++ b/lib/zhong/scheduler.rb
@@ -12,6 +12,7 @@ class Scheduler
 
     def initialize(config = {})
       @jobs = {}
+      @callbacks = {}
       @config = DEFAULT_CONFIG.merge(config)
       @logger = @config[:logger] ||= Util.default_logger
       @redis = @config[:redis] ||= Redis.new(ENV["REDIS_URL"])
@@ -28,7 +29,18 @@ def category(name)
     end
 
     def every(period, name, opts = {}, &block)
-      add(Job.new(name, opts.merge(@config).merge(every: period, category: @category), &block))
+      job = Job.new(name, opts.merge(@config).merge(every: period, category: @category), &block)
+      add(job)
+    end
+
+    def error_handler(&block)
+      @error_handler = block if block_given?
+      @error_handler
+    end
+
+    def on(event, &block)
+      fail "Unsupported callback #{event}" unless [:before_tick, :after_tick, :before_run, :after_run].include?(event.to_sym)
+      (@callbacks[event.to_sym] ||= []) << block
     end
 
     def start
@@ -39,11 +51,20 @@ def start
       @logger.info "starting at #{redis_time}"
 
       loop do
-        now = redis_time
+        if fire_callbacks(:before_tick)
+          now = redis_time
 
-        jobs.each { |_, job| job.run(now) }
+          jobs.each do |_, job|
+            if fire_callbacks(:before_run, job, now)
+              job.run(now)
+              fire_callbacks(:after_run, job, now)
+            end
+          end
 
-        sleep(interval)
+          fire_callbacks(:after_tick)
+
+          sleep(interval)
+        end
 
         break if @stop
       end
@@ -56,6 +77,10 @@ def stop
       Thread.new { @logger.info "stopped" }
     end
 
+    def fire_callbacks(event, *args)
+      @callbacks[event].to_a.all? { |h| h.call(*args) }
+    end
+
     private
 
     def add(job)
diff --git a/lib/zhong/version.rb b/lib/zhong/version.rb
index 1bacfef..eb25575 100644
--- a/lib/zhong/version.rb
+++ b/lib/zhong/version.rb
@@ -1,3 +1,3 @@
 module Zhong
-  VERSION = "0.1.0"
+  VERSION = "0.1.1"
 end