Delete elasticsearch index using logstash output/filter plugin

i need to delete elasticsearch index before insert data. any option is available for logstsah output/filter plugin. i tried some error occur.

please help me

// output {
http {
http_method => "delete"
url => "http://localhost:9200/testdata"
format => "json"
content_type => "application/json"
}
elasticsearch {
hosts => ["http://localhost:9200"]
index => "testdata"
}