That looks OK, if your API is supposed to send availableSpace or node: {...} information it's in the event. If I remember correctly, the stdout output can be seen in journalctl -fu logstash if you want to make sure the events look like you want. Then you can uncomment the Elasticsearch output and see if Kibana picks up the documents.
(Also, copy-pasting logs is easier to read and is indexable for search engines, better than screenshots)