amqp/examples/rpc/amqp_rpc_client.lua

#!/usr/bin/luajit

-- @author 4mig4 <4mig4-github@gmail.com>
-- @release 1.0.0
-- @licence ISC
--
---------------------------------------------------------------------------------
-- Copyright (c) 2018 4mig4 <4mig4-github@gmail.com>
--
-- Permission to use, copy, modify, and distribute this software for any
-- purpose with or without fee is hereby granted, provided that the above
-- copyright notice and this permission notice appear in all copies.
--
-- THE SOFTWARE IS PROVIDED "AS IS" AND THE AUTHOR DISCLAIMS ALL WARRANTIES
-- WITH REGARD TO THIS SOFTWARE INCLUDING ALL IMPLIED WARRANTIES OF
-- MERCHANTABILITY AND FITNESS. IN NO EVENT SHALL THE AUTHOR BE LIABLE FOR
-- ANY SPECIAL, DIRECT, INDIRECT, OR CONSEQUENTIAL DAMAGES OR ANY DAMAGES
-- WHATSOEVER RESULTING FROM LOSS OF USE, DATA OR PROFITS, WHETHER IN AN
-- ACTION OF CONTRACT, NEGLIGENCE OR OTHER TORTIOUS ACTION, ARISING OUT OF
-- OR IN CONNECTION WITH THE USE OR PERFORMANCE OF THIS SOFTWARE.
---------------------------------------------------------------------------------


--       PING PONG (Client) example
--       https://www.rabbitmq.com/direct-reply-to.html

---------------------------------------------------------------------------------
-- Requires

local amqp = require ('amqp')
local uuid = require('resty.uuid')
local inspect = require('inspect')
local argparse = require('argparse')
--local cqueues = require('cqueues')
---------------------------------------------------------------------------------
-- Main
local parser = argparse()
--
-- Instantiate a context
--

local ctx = amqp:new({role = "consumer",
                      exchange = '',
                      queue = 'amq.rabbitmq.reply-to',
                      routing_key = 'test',
                      ssl = false,
                      user = "guest",
                      password = "guest",
                      no_ack = true,
                      durable = true,
                      auto_delete = true,
                      consumer_tag = '',
                      exclusive = false,
                      properties = {}
                    })

--
-- Define callback function that will process the answer (see below)
--

ctx.opts.callback =
  function(f)

    print('---f---',inspect(f))

    if f.body == 'pong' then

      print('received: pong')

      local payload = 'ping'
      local correlation_id = uuid.generate()
      local properties = {
                           reply_to = 'amq.rabbitmq.reply-to',
                           content_type = 'application/json',
                           content_encoding = 'utf-8',
                           correlation_id = correlation_id,
                           delivery_mode = 2,
                           headers = { ['api-version'] = 1,   -- custome headers
                                       correlation_id = correlation_id }
                         }

        local ok, err = ctx:publish(payload, ctx.opts, properties)

        if ok then
          print('replied: ping')
        else
          error('could not publish: '..err)
        end

      end
    end

local function rpc_client(args)
  local host = '127.0.0.1'
  local port = 5672

  if ctx.opts.user and args.user then ctx.opts.user = args.user end
  if ctx.opts.password and args.password then ctx.opts.password = args.password end
  if args.ssl then ctx.opts.ssl = args.ssl end
  if args.host then host = args.host end
  if args.port then port = args.port end

  local ok, err
  ok , err = ctx:connect(host,port)

  if not ok then
    error('could not connect'..err)
  end

  --
  -- Setup connection to AMQP server
  --

  ok, err = ctx:setup() -- because of this we need to use consume_loop()

  if not ok then
    error('could not setup: '..err)
  end

  --
  -- Prepare to consume
  --

  ok, err = ctx:prepare_to_consume() -- this has to be right after setup()

  if not ok then
    error('could not prepare to consume: '..err)
  end

  --
  -- Publish ( AKA send command to PING-PONG server in our case )
  --

  local correlation_id = uuid.generate()
  local properties = { 
                      reply_to = 'amq.rabbitmq.reply-to',
                      content_type = 'application/json',
                      content_encoding = 'utf-8',
                      correlation_id = correlation_id,
                      delivery_mode = 2,
                      headers = { ['api-version'] = 1,
                                  correlation_id = correlation_id }
                    }

  local payload = 'ping'

  ok, err = ctx:publish(payload, ctx.opts, properties)

  if not ok then
    error('could not publish: '..err)
  end

  print('sent: ping')

  --
  -- Wait for answer
  --

  -- Enter consume loop
  -- callback will be called only on reception of BODY_FRAME.
  -- setup() and prepare_to_consume() calls are needed because were are using
  -- consume_loop(callback) method and not consume() method.

  ok = ctx:consume_loop(ctx.opts.callback)

  if not ok then
    error('could not consume loop: ')
  end
end

-- Argument handling ---------------------------------------------------------
parser:option('-H --host','rabbitmq hostname', '127.0.0.1')
parser:option('-P --port','rabbitmq port', 5672)
parser:option('-u --user','rabbitmq username', 'guest')
parser:option('-p --password','rabbitmq password', 'guest')
parser:flag('-s --ssl','enable ssl')

local args = parser:parse()

rpc_client(args)