Hello World TRP in Ruby

Lets look at a sample program in Ruby that sends a Hello Request command to Trisul and gets back a Hello Response.

Also see : Programming model , Messages and Fields

div(info). Pre-requisites You must have Ruby installed on your machine

Step 1 : Install required gems

As root run

  gem install protobuf
  gem install ffi-rzmq

Step 2 : Generate the Ruby TRP definitions

The TRP protocol is completely defined in a file called trp.proto. Download the file and save it in your working directory. You then need to process the trp.proto file and generate bindings for your language.

C:\Users\Vivek\Documents\devbo>protoc trp.proto --ruby_out . ./trp.pb.rb writing...

Step 3 : Save and run this program

Lets get to the good stuff first. Run this program first and understand the output. We can explain the parts in the next section.

Save this program into your working directory.

if RUBY_VERSION =~ /1.8/
  require 'rubygems'
  gem 'ruby_protobuf'
end

require './trp.pb'
begin
  FFI_RZMQ_AVAIL=true
  require 'ffi-rzmq'
rescue
  FFI_RZMQ_AVAIL=false
end

# dispatch and get trp response
def  get_trp_response(endpoint,trp_request,timeout_seconds=-1)

  outbuf=""

  # out
  outbuf=trp_request.encode
  ctx=ZMQ::Context.new
  sock = ctx.socket(ZMQ::REQ)

  # time out for context termination
  sock.setsockopt(ZMQ::LINGER, 5*1_000)

  # Initialize a poll set
  poller = ZMQ::Poller.new
  poller.register(sock, ZMQ::POLLIN)


  sock.connect(endpoint)
  sock.send_string(outbuf)

  ret = poller.poll(timeout_seconds * 1_000 )
  if  ret == -1 
    sock.close
    ctx.terminate 
    raise "zeromq poll error #{endpoint} " 
  end
  if  ret == 0 
    sock.close
    ctx.terminate 
    raise "no registerted sockets #{endpoint} " 
  end

  poller.readables.each do |rsock|
  #in 
  dataarray=""
  rsock.recv_string(dataarray)
  resp =TRP::Message.new
  resp.decode dataarray
  if resp.trp_command.to_i == TRP::Message::Command::ERROR_RESPONSE
    print "TRP ErrorResponse: #{resp.error_response.error_message}\n"
    rsock.close
    ctx.terminate 
    raise resp.error_response.error_message
  end

  rsock.close
  ctx.terminate 
  #unwrap_resp = unwrap_response(resp)
  #unwrap_resp.instance_variable_set("@trp_resp_command_id",resp.trp_command.to_i)
  yield resp if block_given?
  return resp

  end
end


raise "Usage : $0 trp_zmq_endpount" if  ARGV.length !=1
conn = ARGV.shift

# create a new command of type HelloRequest
 request=TRP::Message.new
 request.trp_command = TRP::Message::Command::HELLO_REQUEST
 request.hello_request =TRP::HelloRequest.new
 request.hello_request.station_id = "TRP_TUTORIAL"

get_trp_response(conn,request) do |response|
  puts "Got Hello Response"
  puts "Station ID          : " + response.hello_response.station_id
  puts "Station ID  Request: " + response.hello_response.station_id_request
  puts "Message             : " + response.hello_response.message

end

Run the program

Before you run the program :

1. You need to know the zmq endpoint of the trp server
2. Ensure that the linux firewall allows endpoint connection through

Now run the program

    $ruby testtrp.rb ipc:///usr/local/var/lib/trisul-hub/domain0/hub0/context0/run/trp_0
    
    Got Hello Response
    Got Hello Response
    Station ID          : TRP:1 
    Station ID  Request : TRP_TUTORIAL
    Message             : hello from trp