Add helper method to encapsulate hz check, #2431

lib/sidekiq/util.rb

@@ -51,5 +51,18 @@ module Sidekiq
       end
     end
 
+    def want_a_hertz_donut?
+      # what's a hertz donut?
+      # punch!  Hurts, don't it?
+      info = Sidekiq.redis {|c| c.info }
+      if info['connected_clients'].to_i > 1000 && info['hz'].to_i >= 10
+        Sidekiq.logger.warn { "Your Redis `hz` setting is too high at #{info['hz']}.  See mperham/sidekiq#2431.  Set it to 3 in #{info[:config_file]}" }
+        true
+      else
+        Sidekiq.logger.debug { "Redis hz: #{info['hz']}.  Client count: #{info['connected_clients']}" }
+        false
+      end
+    end
+
   end
 end

test/helper.rb

@@ -32,3 +32,17 @@ REDIS = Sidekiq::RedisConnection.create(:url => REDIS_URL, :namespace => 'testy'
 Sidekiq.configure_client do |config|
   config.redis = { :url => REDIS_URL, :namespace => 'testy' }
 end
+
+def capture_logging(lvl=Logger::INFO)
+  old = Sidekiq.logger
+  begin
+    out = StringIO.new
+    logger = Logger.new(out)
+    logger.level = lvl
+    Sidekiq.logger = logger
+    yield
+    out.string
+  ensure
+    Sidekiq.logger = old
+  end
+end

test/test_sidekiq.rb

@@ -69,11 +69,15 @@ class TestSidekiq < Sidekiq::Test
 
   describe 'error handling' do
     it 'deals with user-specified error handlers which raise errors' do
+      output = capture_logging do
         Sidekiq.error_handlers << proc {|x, hash|
           raise 'boom'
         }
         cli = Sidekiq::CLI.new
         cli.handle_exception(RuntimeError.new("hello"))
       end
+      assert_includes output, "boom"
+      assert_includes output, "ERROR"
+    end
   end
 end

test/test_util.rb

@@ -0,0 +1,18 @@
+require_relative 'helper'
+require 'sidekiq'
+require 'sidekiq/web_helpers'
+
+class TestUtil < Sidekiq::Test
+
+  class Helpers
+    include Sidekiq::Util
+  end
+
+  def test_hertz_donut
+    obj = Helpers.new
+    output = capture_logging(Logger::DEBUG) do
+      assert_equal false, obj.want_a_hertz_donut?
+    end
+    assert_includes output, "hz: 10"
+  end
+end