lua-resty-rabbitmq - Lua RabbitMQ client library which uses cosocket api for communication over STOMP 1.2 with a RabbitMQ broker which has the STOMP plugin.

This library is opinionated and has certain assumptions and limitations which may be addressed in future;

• RabbitMQ server should have the STOMP adapter enabled that supports STOMP v1.2
• Assumption that users, vhost, exchanges, queues and bindings are already setup
• In the first version our aim to implement a client library with persistent publishing to an exchange with some binding and handle RECEIPTs, the focus would be to reuse sockets using cosocktcp sockets.

This library is under development.

This library uses STOMP 1.2 for communication with RabbitMQ broker and implements extensions and restrictions of the RabbitMQ Stomp plugin.

Internally, RabbitMQ uses AMQP to communicate further. This way the library enables implementation of consumers and producers which communicate with the RabbitMQ broker over STOMP, over AMQP. The protocol is frame based and has a command, headers and body terminated by an EOL (^@) which consists of \r (013) and required \n (010) over a TCP stream:

COMMAND
header1:value1
header2: value2

BODY^@

COMMAND is followed by EOL, then EOL separated header in key:value pair format and then a blank line which is where the BODY starts and the frame is terminated by ^@ EOL. COMMAND and headers are UTF-8 encoded.

To connect we create and send a CONNECT frame over a TCP socket provided by the cosocket api connecting to the broker IP, both IPv4 and IPv6 are supported. In the frame we use login, passcode for authentication, accept-version to enforce client STOMP version support and host to select the VHOST of the broker.

CONNECT
accept-version:1.2
login:guest
passcode:guest
host:/devnode
heart-beat:optional

^@

On error, an ERROR frame is returned for example:

ERROR
message:Bad CONNECT
content-type:text/plain
version:1.0,1.1,1.2
content-length:32

Access refused for user 'admin'^@

On successful connection, we are returned a CONNECTED frame by the broker, for example:

CONNECTED
session:session-sGF0vjCKH1bLhFr6w9QwuQ
heart-beat:0,0
server:RabbitMQ/3.0.4
version:1.2

For creating a connection, username, password, vhost, heartbeat, broker host and port should be provided.

We can publish messages to an exchange with a routing key, persistence mode, delivery mode and other header using the SEND command:

SEND
destination:/exchange/exchange_name/routing_key
app-id: luaresty
delivery-mode:2
persistent:true
content-type:json/application
content-length:5

hello^@

Note that content-length includes the message and EOL byte.

FIXME: Add docs on methods

A simple producer that can send reliable persistent message to an exchange with some binding with publisher confirms:

local rabbitmq = require "resty.rabbitmq"

local mq, err = rabbitmq:new()
if not mq then
      return
end

mq:set_timeout(1000)

local ok, err = mq:connect {
                    host = "127.0.0.1",
                    port = 61613,
                    username = "guest",
                    password = "guest",
                    vhost = "/"
                }

if not ok then
    return
end

local msg = "{'a': 'test'}"
local exchange = "test"
local binding = "binding"
local app_id = "luaresty"
local persistent = "true"
local content_type = "application/json"

local ok, err = mq:send(msg, exchange, binding, app_id, persistent, content_type)
if not ok then
    return
end

local ok, err = mq:set_keepalive(0, 10000)
if not ok then
    return
end

• Fix README docs
• Write tests
• Fix all FIXMEs in the code

Rohit "bhaisaab" Yadav, [email protected]

This module is licensed under the MIT license.

Copyright 2013 Rohit "bhaisaab" Yadav, Wingify

Permission is hereby granted, free of charge, to any person obtaining a copy of this software and associated documentation files (the "Software"), to deal in the Software without restriction, including without limitation the rights to use, copy, modify, merge, publish, distribute, sublicense, and/or sell copies of the Software, and to permit persons to whom the Software is furnished to do so, subject to the following conditions:

The above copyright notice and this permission notice shall be included in all copies or substantial portions of the Software.

THE SOFTWARE IS PROVIDED "AS IS", WITHOUT WARRANTY OF ANY KIND, EXPRESS OR IMPLIED, INCLUDING BUT NOT LIMITED TO THE WARRANTIES OF MERCHANTABILITY, FITNESS FOR A PARTICULAR PURPOSE AND NONINFRINGEMENT. IN NO EVENT SHALL THE AUTHORS OR COPYRIGHT HOLDERS BE LIABLE FOR ANY CLAIM, DAMAGES OR OTHER LIABILITY, WHETHER IN AN ACTION OF CONTRACT, TORT OR OTHERWISE, ARISING FROM, OUT OF OR IN CONNECTION WITH THE SOFTWARE OR THE USE OR OTHER DEALINGS IN THE SOFTWARE.

• STOMP 1.2 Spec
• The lua-resty-mysql library
• Openresty google group