I just typed that cURL command and it did not send data to my localhost:9200. It returned null line.
Each json seperated from each other by new line.For example like this:
{"type": "server", "timestamp": "2019-12-07T19:09:46,351Z", "level": "INFO", "component": "o.e.e.NodeEnvironment", "cluster.name": "docker-cluster", "node.name": "f97588749c79", "message": "heap size [989.8mb], compressed ordinary object pointers [true]" }
{"type": "server", "timestamp": "2019-12-07T19:09:46,353Z", "level": "INFO", "component": "o.e.n.Node", "cluster.name": "docker-cluster", "node.name": "f97588749c79", "message": "node name [f97588749c79], node ID [qJbs-xKRTxiaoIGXbrsVkg], cluster name [docker-cluster]" }