Elastic Search Logstash how to query all fields and get all fields into pipeline?

[MLsuper]

So I have a logstash pipeline that is currently setup with this: for a query

input {
  hosts => ...
  query => '{ "query": {
                          "match_all": {}
    }}'
  target => "[@metasource][_source]"
  index=>...
  user=>...
  password=>...

}

 output{
  hosts => ...
  user=>...
  password=>...
  index=>...

}

I have a Elasticsearch input for a existing index and my output is an Elasticsearch output for a new index

however when I start the pipeline I only receive documents with default fields, I want all the fields of each document in the existing index.

So basically I want my input and output index the same
so both indexes same replica

also and how would I want "specific fields"?

thank you so much please!