This is an adapter to the kestrel messaging server for the ActiveMessaging framework. It is in the early stages of development.
- send to any queue
- receive from any subscribed queue
require 'activemessaging-kestrel-adapter' # configure ActiveMessaging broker in an appropriate broker.yml file: # development: # adapter: kestrel # servers: localhost:22133 # empty_queues_delay: 0.1 # retry_policy: # strategy: SimpleRetry # config: # tries: 1 # delay: 5 # the retry_policy: second is optional and should be left out under # most circumstances (see below). config = YAML.load(File.read("broker.yml")) adapter = ActiveMessaging::Adapters::Kestrel::Connection.new(config[:development]) adapter.send("arbitrarily_named_queue", "message as string") adapter.subscribe("queue1") adapter.subscribe("queue2") adapter.receive # get a message from any of the subscribed queues, or nil if they are all empty
See the ActiveMessaging project for details of broker configuration. This Kestrel adapter can be configured with a retry_policy, but it is not necessary to do so as a sensible default will be used if the configuration is not present. The default policy is as shown above. The default policy in the face of receive exceptions is to sleep 5 seconds, then retry once. If an exception still occurs, it is raised. The strategy must refer to a class that once instantiated, responds to the do_work() method. The method must take a options hash. The value of the options hash will be the config: key in the configuration file. For 99% of use cases, you should not even bother defining the retry_policy as the default is fine. The ability to override the policy is provided for edge cases.
empty_queues_delay is provided as a hack for when this adapter is used by the ActiveMessaging::Gateway messaging loop. Without setting this to some small non zero value, the messaging loop will consume 100% of CPU if there are no messages in subscribed queues. If you are using this adapter outside of the ActiveMessaging::Gateway messaging loop, do not set this key, but beware of CPU burn if you call ActiveMessaging::Adapters::Kestrel::Connection#receive in a loop and there are no messages in the subscribed queues.
- activemessaging >= 0.9.0
- Handle a cluster of kestrel servers
- gem install activemessaging-kestrel-adapter
Original author: Douglas A. Seifert email@example.com
The MIT License
Copyright (c) 2011-2012 Douglas A. Seifert
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