gnmic supports exporting subscription updates to a TCP server

A TCP output can be defined using the below format in gnmic config file under outputs section:

    - type: tcp # required
      address: IPAddress:Port # a UDP server address 
      rate: 10ms # maximum sending rate, e.g: 1ns, 10ms
      buffer-size: # number of messages to buffer in case of sending failure
      format: json # export format. json, protobuf, prototext, protojson, event
      keep-alive: # enable TCP keepalive and specify the timer, e.g: 1s, 30s
      retry-interval: # time duration to wait before re-dial in case there is a failure

A TCP output can be used to export data to an ELK stack, using Logstash TCP input