Remove race condition at ceilometer::db initialisation

On the first run, the ceilometer::db class was failing due to the fact
that the MongoDB service was not actually listening yet when it came
to it. It return with an ERRNO 111 - ECONNREFUSED.

This patch adds a dependency to ceilometer::db, this dependency ensure
that the MongoDB service is listening before giving the hand to ceilometer::db.

close #13

manifests/telemetry/server.pp

@@ -27,10 +27,19 @@ class cloud::telemetry::server(
 
   include 'cloud::telemetry'
 
-# Install MongoDB database
+  $db_conn = regsubst($ceilometer_database_connection, 'mongodb:\/\/(\.*)', '\2')
+  exec {'check_mongodb' :
+    command   => "/usr/bin/mongo ${db_conn}",
+    logoutput => false,
+    tries     => 60,
+    try_sleep => 5,
+    require   => Service['mongodb'],
+  }
+
+  # Install MongoDB database
   class { 'ceilometer::db':
     database_connection => $ceilometer_database_connection,
-    require             => Class['mongodb']
+    require             => Exec['check_mongodb'],
   }
 
 # Install Ceilometer-collector

spec/classes/privatecloud_telemetry_server_spec.rb

@@ -61,6 +61,12 @@ describe 'cloud::telemetry::server' do
       should contain_ceilometer_config('DEFAULT/use_syslog').with('value' => 'yes')
     end
 
+    it 'check mongodb is started' do
+      should contain_exec('check_mongodb').with({
+        :command => '/usr/bin/mongo 10.0.0.2/ceilometer',
+      })
+    end
+
     it 'configure ceilometer db' do
       should contain_class('ceilometer::db').with(
           :database_connection => 'mongodb://10.0.0.2/ceilometer'