Timestamp replaced

and this is my current config

input {
	file {
		path => "/Users/apple/Desktop/Logstash_trial_3/event.log.20180214"
		start_position => "beginning"
		sincedb_path => "/dev/null"
		codec => json

	}
}

filter {
	json{
		source => "message"
		#target =>"doc"
		remove_field => ["message"]
	}
	mutate{
		rename => ["_id" , "ID"]
	}

}

output {
	elasticsearch {
		hosts => "localhost:9200"
		index => "realrollingdata"
		document_type => "eventdata"
	}
	stdout {}
	
}