Implement remote signals via heartbeat

Changes.md

@@ -1,3 +1,20 @@
+3.1.0
+-----------
+
+- New remote signals feature: you can remotely trigger Sidekiq to quiet
+  or terminate remotely via API, without signals.  This is most useful
+  on Heroku which does not support the USR1 'quiet' signal.  Now you can
+  run a rake task like this at the start of your deploy to quiet your
+  set of Sidekiq processes.
+```ruby
+namespace :sidekiq do
+  task :quiet => :environment do
+    Sidekiq::ProcessSet.new.each(&:quiet!)
+  end
+end
+```
+
+
 3.0.2
 -----------
 

lib/sidekiq/api.rb

@@ -514,6 +514,22 @@ module Sidekiq
     def [](key)
       @attribs[key]
     end
+
+    def quiet!
+      key = "#{identity}-signals"
+      Sidekiq.redis do |c|
+        c.multi do
+          c.lpush(key, 'USR1')
+          c.expire(key, 60)
+        end
+      end
+    end
+
+    private
+
+    def identity
+      @id ||= "#{self['hostname']}:#{self['pid']}"
+    end
   end
 
   ##

lib/sidekiq/cli.rb

@@ -95,16 +95,6 @@ module Sidekiq
 
     private
 
-    def fire_event(event)
-      Sidekiq.options[:lifecycle_events][event].each do |block|
-        begin
-          block.call
-        rescue => ex
-          handle_exception(ex, { :event => event })
-        end
-      end
-    end
-
     def handle_signal(sig)
       Sidekiq.logger.debug "Got #{sig} signal"
       case sig

lib/sidekiq/manager.rb

@@ -149,12 +149,15 @@ module Sidekiq
 
     def ❤(key)
       begin
-        Sidekiq.redis do |conn|
+        _, _, msg = Sidekiq.redis do |conn|
           conn.multi do
             conn.hmset(key, 'busy', @busy.size, 'beat', Time.now.to_f)
             conn.expire(key, 60)
+            conn.rpop("#{key}-signals")
           end
         end
+
+        ::Process.kill(msg, $$) if msg
       rescue => e
         # ignore all redis/network issues
         logger.error("heartbeat: #{e.message}")

lib/sidekiq/util.rb

@@ -33,5 +33,16 @@ module Sidekiq
     def identity
       @@identity ||= "#{hostname}:#{$$}"
     end
+
+    def fire_event(event)
+      Sidekiq.options[:lifecycle_events][event].each do |block|
+        begin
+          block.call
+        rescue => ex
+          handle_exception(ex, { :event => event })
+        end
+      end
+    end
+
   end
 end

lib/sidekiq/version.rb

@@ -1,3 +1,3 @@
 module Sidekiq
-  VERSION = "3.0.2"
+  VERSION = "3.1.0"
 end