ES 8.18.3 - ruby api: getting "<Elastic::Transport::Transport::Error: Net::ReadTimeout with #<TCPSocket:(closed)>>"

Elastic Stack Elasticsearch
1

I have a ruby program that ingests data into ES (using bulk)

I am seeing periodic failures on bulk uploads which raise exception <Elastic::Transport::Transport::Error: Net::ReadTimeout with #<TCPSocket:(closed)>>

These come in cluster so I assume they are trigged by load on the clusters.

We recently upgraded to version 8 which does not have a separate elasticsearch-transport gem. I had code that handled these but now there are no exception constants for Elastic::Transport.

How can I trap these errors?

current code:

    index_params= { index: index_n,  body: batch } # timeout: 10,K body: batch }                                                                                                                                                 
    begin
      r = @conn.perform_api_request(:bulk, index_params, true )
#    rescue Elasticsearch::Transport::Transport::Errors => e                                                                                                                                                                     
#      $logger.warn "bulk error #{e.message}"                                                                                                                                                                                    
#      @transport_failure = true                                                                                                                                                                                                 
    rescue => e
      $logger.warn "bulk error #{e.inspect}" # .message}"                                                                                                                                                                        
      if e.message == 'execution expired' or e.message.match(/^Failed to open/)  # timeout                                                                                                                                       
        @transport_failure = true
      end
    end

with the pre version 8 code commented.

now outputs

[2025-11-26T10:50:32] WARN  : bulk error #<Elastic::Transport::Transport::Error: Net::ReadTimeout with #<TCPSocket:(closed)>>
[2025-11-26T10:50:42] WARN  : bulk error #<Elastic::Transport::Transport::Error: Net::ReadTimeout with #<TCPSocket:(closed)>>

Also and ideas about what is causing the problem at the ES end

Grasping at straws I have reduced the batch size to 1000 from 5000. docs are small - order of 1KB with less than a dozen fields