Merge pull request hirefire#14 from samoli/minimum_workers.

Add min_workers option

README.md

@@ -44,6 +44,7 @@ And that's it. Next time you deploy to [Heroku](http://heroku.com/) it'll automa
     HireFire.configure do |config|
       config.environment      = nil # default in production is :heroku. default in development is :noop
       config.max_workers      = 5   # default is 1
+      config.min_workers      = 0   # default is 0
       config.job_worker_ratio = [
           { :jobs => 1,   :workers => 1 },
           { :jobs => 15,  :workers => 2 },

lib/hirefire/configuration.rb

@@ -8,6 +8,12 @@ class Configuration
     #
     # @return [Fixnum] default: 1
     attr_accessor :max_workers
+
+    ##
+    # Contains the min amount of workers that should always be running
+    #
+    # @return [Fixnum] default: 0
+    attr_accessor :min_workers
 
     ##
     # Contains the job/worker ratio which determines
@@ -33,6 +39,7 @@ class Configuration
     # @return [HireFire::Configuration]
     def initialize
       @max_workers      = 1
+      @min_workers      = 0
       @job_worker_ratio = [
           { :jobs => 1,   :workers => 1 },
           { :jobs => 25,  :workers => 2 },

lib/hirefire/environment/base.rb

@@ -160,13 +160,13 @@ def hire
       # or "updated, unless the job didn't fail"
       #
       # If there are workers active, but there are no more pending jobs,
-      # then fire all the workers
+      # then fire all the workers or set to the minimum_workers
       #
       # @return [nil]
       def fire
-        if jobs == 0 and workers > 0
-          Logger.message("All queued jobs have been processed. Firing all workers.")
-          workers(0)
+        if jobs == 0 and workers > min_workers
+          Logger.message("All queued jobs have been processed. " + (min_workers > 0 ? "Setting workers to #{min_workers}." : "Firing all workers."))
+          workers(min_workers)
         end
       end
 
@@ -189,6 +189,15 @@ def log_and_hire(amount)
       def max_workers
         HireFire.configuration.max_workers
       end
+
+      ##
+      # Wrapper method for HireFire.configuration
+      # Returns the min amount of workers that should always be running
+      #
+      # @return [Fixnum] the min amount of workers that should always be running
+      def min_workers
+        HireFire.configuration.min_workers
+      end
 
       ##
       # Wrapper method for HireFire.configuration

spec/configuration_spec.rb

@@ -9,6 +9,7 @@
 
     configuration.environment.should      == nil
     configuration.max_workers.should      == 1
+    configuration.min_workers.should      == 0
     configuration.job_worker_ratio.should == [
         { :jobs => 1,   :workers => 1 },
         { :jobs => 25,  :workers => 2 },
@@ -22,6 +23,7 @@
     HireFire.configure do |config|
       config.environment      = :noop
       config.max_workers      = 10
+      config.min_workers      = 0
       config.job_worker_ratio = [
           { :jobs => 1,   :workers => 1 },
           { :jobs => 15,  :workers => 2 },
@@ -35,6 +37,7 @@
 
     configuration.environment.should      == :noop
     configuration.max_workers.should      == 10
+    configuration.min_workers.should      == 0
     configuration.job_worker_ratio.should == [
         { :jobs => 1,   :workers => 1 },
         { :jobs => 15,  :workers => 2 },

spec/environment_spec.rb

@@ -100,6 +100,16 @@ def jobs=(amount)
       base.expects(:workers).with(0).once
       base.fire
     end
+
+    it 'should set the workers to minimum workers when there arent any jobs' do
+      base.jobs    = 0
+      base.workers = 10
+      base.stubs(:min_workers).returns(2)
+
+      HireFire::Logger.expects(:message).with('All queued jobs have been processed. Setting workers to 2.')
+      base.expects(:workers).with(2).once
+      base.fire
+    end
   end
 
   describe '#hire' do