• kdb+

  Creating heartbeat monitor for server-client

  Posted by ngumbo on March 4, 2022 at 12:00 am

  What would be the way of going about creating a heartbeat table server side to monitor response times to each of the servers clients. I have been exploring this but am unsure on how to send a message from server to client and only know how to do client to server messages. To measure response time I can use a timer just unsure on how to go about sending the message?

  ngumbo replied 8 months, 1 week ago 2 Members · 3 Replies
• 3 Replies

• 

  pmallon

  Member

  March 4, 2022 at 12:00 am

  Hi,

  Is there a specific reason for server>client?

  I have tried to cover both below, hopefully it is at least a starter for you and helps..

  q)/server process
  q)p 50001
  q)/ heartbeat table to log hbs
  q)heartbeat:([host:`$();port:`long$()];hdl:`int$();lastPing:`timestamp$();pings:`long$())
  q)/function to log hearbeat on server
  q)registerHeartBeat:{[hst;prt] `heartbeat upsert (hst;prt;.z.w;.z.p;)1+0^first exec pings from heartbeat where host=hst,port=prt }

   

  q)/client process
  q)p 50000
  q)/ hdl to server
  q).R.Server:hopen `::50001
  q)/ send heartbeat from client to server
  q)sendHeartBeat:{ .R.Server (`registerHeartBeat;.z.h;system "p")}
  q)/ call send a heart beat from client to server
  q)sendHeartBeat[] / this could be on a timer
  `heartbeat
  
  // check on the server 
  q)heartbeat
  host port | hdl lastPing pings
  ---------------------| ---------------------------------------
  desktop 50000| 9 2022.03.04D12:31:48.583133000 1

   

  / initiating from server side
  / have each client process register with the server on startup (for this I have just manually called sendHeartBeat from client) 
  / to add hdls to heartbeat table
  
  q)/ callback type idea to initiate a registerHeartBeat call
  q)reportToServer:{ .z.w (`registerHeartBeat;.z.h;system "p")}
  q)/ this function on server would request a heart beat from each hdl in the heartbeat table
  q)getHeartBeatFromServer:{ (exec distinct hdl from heartbeat)@:(reportToServer;`)}
  q)/ call above function, which could be on a timer
  q)getHeartBeatFromServer[]
  ,`heartbeat
  q)heartbeat
  host port | hdl lastPing pings
  ---------------------| ---------------------------------------
  desktop 50000| 9 2022.03.04D12:33:28.583133000 2
  
  
  

  Thanks

   

• 

  ngumbo

  Member

  March 7, 2022 at 12:00 am

  Hey Patrick, thanks again for the detailed response its much appreciated, I believe it is requested to be done server side so no setup has to be done client side regardless of which clients are connecting in.

• 

  pmallon

  Member

  March 7, 2022 at 12:00 am

  Yea Ok, that’s a fair point.  In that case hopefully the 2nd point above helps get you started… if not let me know.

  thanks

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