activemessaging-kestrel-adapter

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
• memcache-client
• active_support
• active_support/core_ext
• i18n

• Handle a cluster of kestrel servers

• gem install activemessaging-kestrel-adapter

Original author: Douglas A. Seifert doug@dseifert.net

The MIT License

Copyright (c) 2011-2012 Douglas A. Seifert

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.

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