module NebulousStomp

NebulousStomp

¶ ↑

A little module that implements The Nebulous Protocol, a way of passing data over STOMP between different systems. Specifically, it allows you to send a message, a Request, and receive another message in answer, a Response. (Which is not something STOMP does, out of the box).

This library covers two specific use cases (three if you are picky):

1) Request-Response: a program that consumes incoming messages, works out what message to
   send in response, and sends it.

2) Question-Answer: a program that sends a request and then waits for a response; the other
   end of the Request-Response use case. We support optional caching of responses in Redis,
   to speed things up if your program is likely to make the same request repeatedly within a
   short time.

3) Since we are talking to Redis, we expose a basic, simple interface for you to talk to it
   yourself.

These are the externally-facing classes:

* Listener      -- implements the request-response use case
* Message       -- a Nebulous-Stomp message
* NebulousStomp -- main class
* RedisHelper   -- implements the Redis use case
* Request       -- implements the Request-Response use case; a wrapper for Message
* Target        -- represents a single Target

These classes are used internally:

* Param            -- helper class to store and return configuration
* RedisHandler     -- internal class to wrap the Redis gem
* RedisHandlerNull -- a "mock" version of  RedisHandler for use in testing
* StompHandler     -- internal class to wrap the Stomp gem
* StompHandlerNull -- a "mock" version of StompHandler for use in testing

Constants

VERSION: Nebulous version number

Public Class Methods

add_target(name, targetHash) → Target click to toggle source

Add a Nebulous target called <name> with a details as per <targetHash>.

<targetHash> must contain a send queue and a receive queue, or a NebulousError will be raised. Have a look in NebulousStomp::Target for the default hash you are overriding here.

Note that Param expects the target hash to have a :name key. We don’t; we add it in.

# File lib/nebulous_stomp.rb, line 90
def self.add_target(name, targetHash) 
  t = NebulousStomp::Target.new targetHash.merge(name: name)
  Param.add_target(t)
  t
end

get_target(name) # → Target click to toggle source

Given a target name, return the Target object.

# File lib/nebulous_stomp.rb, line 102
def self.get_target(name)
  Param.get_target(name)
end

init(paramHash) → (nil) click to toggle source

Initialise library for use and override default options with any in <paramHash>.

The default options are defined in Nebulous::Param.

# File lib/nebulous_stomp.rb, line 74
def self.init(paramHash={}) 
  Param.set(paramHash)
  nil
end

logger.info(__FILE__) { "message" } click to toggle source

Return a Logger instance to log things to. If one was not given to Param, return a logger instance that uses a DevNull IO object, that is, goes nowhere.

# File lib/nebulous_stomp.rb, line 123
def self.logger
  Param.get_logger || Logger.new( DevNull.new )
end

on? → Boolean click to toggle source

True if Nebulous is configured to be running

# File lib/nebulous_stomp.rb, line 133
def self.on?
  h = Param.get(:stompConnectHash)
  !(h.nil? || h.empty?)
end

redis_on? → Boolean click to toggle source

True if the Redis cache is configured to be running

# File lib/nebulous_stomp.rb, line 144
def self.redis_on?
  h = Param.get(:redisConnectHash)
  !(h.nil? || h.empty?)
end

set_logger(Logger.new STDOUT) click to toggle source

Set an instance of Logger to log stuff to.

# File lib/nebulous_stomp.rb, line 112
def self.set_logger(logger)
  Param.set_logger(logger)
end