(RE-7014) Add support for statsd

They way we were using graphite was incorrect for the type of data we were sending it.  statsd is the appropriate mechanism for our needs.
statsd and graphite are mutually exclusive and configuring statsd will take precendence over Graphite.  Example of configuration in vmpooler.yaml.example

spec/spec_helper.rb

@@ -1,3 +1,7 @@
+require 'simplecov'
+SimpleCov.start do
+  add_filter '/spec/'
+end
 require 'helpers'
 require 'rbvmomi'
 require 'rspec'

spec/vmpooler/pool_manager_spec.rb

@@ -5,13 +5,12 @@ describe 'Pool Manager' do
   let(:logger) { double('logger') }
   let(:redis) { double('redis') }
   let(:config) { {} }
-  let(:graphite) { nil }
   let(:pool) { 'pool1' }
   let(:vm) { 'vm1' }
   let(:timeout) { 5 }
   let(:host) { double('host') }
 
-  subject { Vmpooler::PoolManager.new(config, logger, redis, graphite) }
+  subject { Vmpooler::PoolManager.new(config, logger, redis) }
 
   describe '#_check_pending_vm' do
     let(:pool_helper) { double('pool') }
@@ -252,6 +251,65 @@ describe 'Pool Manager' do
     end
   end
 
+  describe '#_stats_running_ready' do
+    let(:pool_helper) { double('pool') }
+    let(:vsphere) { {pool => pool_helper} }
+    let(:graphite) { double('graphite') }
+    let(:config) { {
+      config: { task_limit: 10 },
+      pools: [ {'name' => 'pool1', 'size' => 5} ],
+      graphite: { 'prefix' => 'vmpooler' }
+    } }
+
+    before do
+      expect(subject).not_to be_nil
+      $vsphere = vsphere
+      allow(logger).to receive(:log)
+      allow(pool_helper).to receive(:find_folder)
+      allow(redis).to receive(:smembers).and_return([])
+      allow(redis).to receive(:set)
+      allow(redis).to receive(:get).with('vmpooler__tasks__clone').and_return(0)
+      allow(redis).to receive(:get).with('vmpooler__empty__pool1').and_return(nil)
+    end
+
+    context 'graphite' do
+      let(:graphite) { double('graphite') }
+      subject { Vmpooler::PoolManager.new(config, logger, redis, graphite) }
+
+      it 'increments graphite when enabled and statsd disabled' do
+        allow(redis).to receive(:scard).with('vmpooler__ready__pool1').and_return(1)
+        allow(redis).to receive(:scard).with('vmpooler__cloning__pool1').and_return(0)
+        allow(redis).to receive(:scard).with('vmpooler__pending__pool1').and_return(0)
+        allow(redis).to receive(:scard).with('vmpooler__running__pool1').and_return(5)
+
+        expect(graphite).to receive(:log).with('vmpooler.ready.pool1', 1)
+        expect(graphite).to receive(:log).with('vmpooler.running.pool1', 5)
+        subject._check_pool(config[:pools][0])
+      end
+    end
+
+    context 'statsd' do
+      let(:statsd) { double('statsd') }
+      let(:config) { {
+        config: { task_limit: 10 },
+        pools: [ {'name' => 'pool1', 'size' => 5} ],
+        statsd: { 'prefix' => 'vmpooler' }
+      } }
+      subject { Vmpooler::PoolManager.new(config, logger, redis, graphite, statsd) }
+
+      it 'increments statsd when configured' do
+        allow(redis).to receive(:scard).with('vmpooler__ready__pool1').and_return(1)
+        allow(redis).to receive(:scard).with('vmpooler__cloning__pool1').and_return(0)
+        allow(redis).to receive(:scard).with('vmpooler__pending__pool1').and_return(0)
+        allow(redis).to receive(:scard).with('vmpooler__running__pool1').and_return(5)
+
+        expect(statsd).to receive(:increment).with('vmpooler.ready.pool1', 1)
+        expect(statsd).to receive(:increment).with('vmpooler.running.pool1', 5)
+        subject._check_pool(config[:pools][0])
+      end
+    end
+  end
+
   describe '#_create_vm_snapshot' do
     let(:snapshot_manager) { 'snapshot_manager' }
     let(:pool_helper) { double('snapshot_manager') }