Logstash reading in XML files to Elasticsearch

I have the following logstash conf file:

input {
  stdin {
    type => "stdin-type"
  }

  file {
     type => "file"
     path => "/Users/jhwhite/Downloads/search_result/*.xml"
    }
}

output {
  stdout { }
  elasticsearch { host => "localhost" protocol => "http" }
}

When I run bin/logstash -f logstash-simple.conf I get the following error:

Exception in thread ">output" org.elasticsearch.discovery.MasterNotDiscoveredException: waited for [30s]
    at org.elasticsearch.action.support.master.TransportMasterNodeOperationAction$3.onTimeout(org/elasticsearch/action/support/master/TransportMasterNodeOperationAction.java:180)
    at org.elasticsearch.cluster.service.InternalClusterService$NotifyTimeout.run(org/elasticsearch/cluster/service/InternalClusterService.java:492)
    at java.util.concurrent.ThreadPoolExecutor.runWorker(java/util/concurrent/ThreadPoolExecutor.java:1142)
    at java.util.concurrent.ThreadPoolExecutor$Worker.run(java/util/concurrent/ThreadPoolExecutor.java:617)
    at java.lang.Thread.run(java/lang/Thread.java:745)

When I run the getting started guide from Logstash (http://ift.tt/1lb9SyY) I get the same thing trying to read in from an external conf file.

How do I get Logstash to read in a collection of external xml files?