<match worker.**>
  @type route
  remove_tag_prefix worker
  <route **>
    add_tag_prefix metrics.event
    copy # For fall-through. Without copy, routing is stopped here. 
  </route>
  <route **>
    add_tag_prefix backup
    copy
  </route>
</match>

<match metrics.event.**>
  @type stdout
</match>

<match backup.**>
  @type file
  path /var/log/fluent/bakcup
</match>

<match worker.**>
  @type route
  remove_tag_prefix worker
  add_tag_prefix metrics.event
  <route **>
    copy
  </route>
  <route **>
    copy
    @label @BACKUP
  </route>
</match>

<match metrics.event.**>
  @type stdout
</match>

<label @BACKUP>
  <match metrics.event.**>
    @type file
    path /var/log/fluent/bakcup
  </match>
</label>