From 7f51db4ee309ecee29963ec1355ebc9bc9769ae6 Mon Sep 17 00:00:00 2001
From: Mike Perham <mperham@gmail.com>
Date: Thu, 23 May 2013 22:58:06 -0700
Subject: [PATCH] Add Sidekiq::Queue#latency

---
 Changes.md             |  4 +++-
 lib/sidekiq/api.rb     |  8 ++++++++
 lib/sidekiq/version.rb |  2 +-
 test/test_api.rb       | 10 +++++++---
 4 files changed, 19 insertions(+), 5 deletions(-)

diff --git a/Changes.md b/Changes.md
index f40d4021..32deddd5 100644
--- a/Changes.md
+++ b/Changes.md
@@ -2,7 +2,9 @@ HEAD
 -----------
 
 - Record the timestamp when jobs are enqueued. Add
-  Sidekiq::Stats::Job#enqueued_at to query the time. [mariovisic, #944]
+  Sidekiq::Job#enqueued\_at to query the time. [mariovisic, #944]
+- Add Sidekiq::Queue#latency - calculates diff between now and
+  enqueued\_at for the oldest job in the queue.
 
 2.12.0
 -----------
diff --git a/lib/sidekiq/api.rb b/lib/sidekiq/api.rb
index 2e1af1bf..100b542f 100644
--- a/lib/sidekiq/api.rb
+++ b/lib/sidekiq/api.rb
@@ -128,6 +128,14 @@ module Sidekiq
       Sidekiq.redis { |con| con.llen(@rname) }
     end
 
+    def latency
+      entry = Sidekiq.redis do |conn|
+        conn.lrange(@rname, -1, -1)
+      end.first
+      return 0 unless entry
+      Time.now.to_f - Sidekiq.load_json(entry)['enqueued_at']
+    end
+
     def each(&block)
       page = 0
       page_size = 50
diff --git a/lib/sidekiq/version.rb b/lib/sidekiq/version.rb
index ed42424a..e434da6b 100644
--- a/lib/sidekiq/version.rb
+++ b/lib/sidekiq/version.rb
@@ -1,3 +1,3 @@
 module Sidekiq
-  VERSION = "2.12.0"
+  VERSION = "2.12.1"
 end
diff --git a/test/test_api.rb b/test/test_api.rb
index 1dac7b9c..77c5284d 100644
--- a/test/test_api.rb
+++ b/test/test_api.rb
@@ -164,6 +164,7 @@ class TestApi < Minitest::Test
     it 'shows queue as empty' do
       q = Sidekiq::Queue.new
       assert_equal 0, q.size
+      assert_equal 0, q.latency
     end
 
     class ApiWorker
@@ -171,8 +172,8 @@ class TestApi < Minitest::Test
     end
 
     it 'can enumerate jobs' do
+      q = Sidekiq::Queue.new
       Time.stub(:now, Time.new(2012, 12, 26)) do
-        q = Sidekiq::Queue.new
         ApiWorker.perform_async(1, 'mike')
         assert_equal ['TestApi::ApiWorker'], q.map(&:klass)
 
@@ -181,9 +182,12 @@ class TestApi < Minitest::Test
         assert_equal [1, 'mike'], job.args
         assert_equal Time.new(2012, 12, 26), job.enqueued_at
 
-        q = Sidekiq::Queue.new('other')
-        assert_equal 0, q.size
       end
+
+      assert q.latency > 10_000_000
+
+      q = Sidekiq::Queue.new('other')
+      assert_equal 0, q.size
     end
 
     it 'can delete jobs' do