Add Sidekiq::Workers API, closes #639

Changes.md

@@ -1,6 +1,19 @@
 HEAD
 -----------
 
+- Add Sidekiq::Workers API giving programmatic access to the current
+  set of active workers.
+
+```
+workers = Sidekiq::Workers.new
+workers.size => 2
+workers.each do |name, work|
+  # name is a unique identifier per Processor instance
+  # work is a Hash which looks like:
+  # { 'queue' => name, 'run_at' => timestamp, 'payload' => msg }
+end
+```
+
 - Allow environment-specific sections within the config file which
 override the global values [dtaniwaki, #630]
 

lib/sidekiq/api.rb

@@ -333,4 +333,43 @@ module Sidekiq
     end
   end
 
+
+  ##
+  # Programmatic access to the current active worker set.
+  #
+  # WARNING WARNING WARNING
+  #
+  # This is live data that can change every millisecond.
+  # If you do #size => 5 and then expect #each to be
+  # called 5 times, you're going to have a bad time.
+  #
+  #    workers = Sidekiq::Workers.new
+  #    workers.size => 2
+  #    workers.each do |name, work|
+  #      # name is a unique identifier per Processor instance
+  #      # work is a Hash which looks like:
+  #      # { 'queue' => name, 'run_at' => timestamp, 'payload' => msg }
+  #    end
+
+  class Workers
+    include Enumerable
+
+    def each(&block)
+      Sidekiq.redis do |conn|
+        workers = conn.smembers("workers")
+        workers.each do |w|
+          msg = conn.get("worker:#{w}")
+          next unless msg
+          block.call(w, Sidekiq.load_json(msg))
+        end
+      end
+    end
+
+    def size
+      Sidekiq.redis do |conn|
+        conn.scard("workers")
+      end.to_i
+    end
+  end
+
 end

test/test_api.rb

@@ -269,6 +269,29 @@ class TestApi < MiniTest::Unit::TestCase
       assert_equal 0, r.size
     end
 
+    it 'can enumerate workers' do
+      w = Sidekiq::Workers.new
+      assert_equal 0, w.size
+      w.each do |x, y|
+        assert false
+      end
+
+      s = '12345'
+      data = Sidekiq.dump_json({ 'payload' => {}, 'queue' => 'default', 'run_at' => Time.now.to_i })
+      Sidekiq.redis do |c| 
+        c.multi do
+          c.sadd('workers', s)
+          c.set("worker:#{s}", data)
+        end
+      end
+
+      assert_equal 1, w.size
+      w.each do |x, y|
+        assert_equal s, x
+        assert_equal 'default', y['queue']
+      end
+    end
+
     def add_retry(jid = 'bob', at = Time.now.to_f)
       payload = Sidekiq.dump_json('class' => 'ApiWorker', 'args' => [1, 'mike'], 'queue' => 'default', 'jid' => jid, 'retry_count' => 2, 'failed_at' => Time.now.utc)
       Sidekiq.redis do |conn|