Merge pull request #559 from bobtfish/event_sprintf_fixnums

Small fix for logstash/event.rb's sprintf method.

lib/logstash/event.rb

@@ -205,6 +205,7 @@ class LogStash::Event
   # is an array (or hash?) should be. Join by comma? Something else?
   public
   def sprintf(format)
+    format = format.to_s
     if format.index("%").nil?
       return format
     end

spec/event.rb

@@ -45,6 +45,10 @@ describe LogStash::Event do
       insist { subject.sprintf("%{[j][k1]}") } == "v"
       insist { subject.sprintf("%{[j][k2][0]}") } == "w"
     end
+
+    it "should be able to take a non-string for the format" do
+      insist { subject.sprintf(2) } == "2"
+    end
   end
   
   context "#[]" do