Setup plugin sketch

logstash.conf

input {
  setup {
    ns => "connection"
    params => {
      host => "127.0.0.1"
      port => 6666
      username => "user"
      password => "the pwd"
    }
  }
  couchdb_changes {
    merge_from_ns => "connection" # will put the params defined above into the local context 
    db => "mydb" # other params, possibly allow to overwrite ns-params
  }
  couchdb_changes {
    merge_from_ns => "connection"
    db => "myotherdb"
  }
}