Class: ActiveMessaging::Adapters::AmazonSqs::Connection

Inherits:
BaseConnection
  • Object
show all
Defined in:
lib/activemessaging/adapters/asqs.rb

Constant Summary collapse

QUEUE_NAME_LENGTH = 
1..80
VISIBILITY_TIMEOUT = 
0..(24 * 60 * 60)
NUMBER_OF_MESSAGES = 
1..255
GET_QUEUE_ATTRIBUTES = 
['All', 'ApproximateNumberOfMessages', 'VisibilityTimeout']
SET_QUEUE_ATTRIBUTES = 
['VisibilityTimeout']

Instance Attribute Summary collapse

Attributes inherited from BaseConnection

#reliable

Instance Method Summary collapse

Methods included from ActiveMessaging::Adapter

included, #logger

Constructor Details

#initialize(cfg) ⇒ Connection

generic init method needed by a13g



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# File 'lib/activemessaging/adapters/asqs.rb', line 30

def initialize cfg
  raise "Must specify a access_key_id" if (cfg[:access_key_id].nil? || cfg[:access_key_id].empty?)
  raise "Must specify a secret_access_key" if (cfg[:secret_access_key].nil? || cfg[:secret_access_key].empty?)

  @access_key_id=cfg[:access_key_id]
  @secret_access_key=cfg[:secret_access_key]
  @request_expires = cfg[:requestExpires]         || 10
  @request_retry_count = cfg[:requestRetryCount]  || 5
  @aws_version = cfg[:aws_version]                || '2008-01-01'
  @content_type = cfg[:content_type]              || 'text/plain'
  @host = cfg[:host]                              || 'queue.amazonaws.com'
  @port = cfg[:port]                              || 80
  @protocol = cfg[:protocol]                      || 'http'
  @poll_interval = cfg[:poll_interval]            || 1
  @reconnect_delay = cfg[:reconnectDelay]         || 5

  @max_message_size = cfg[:max_message_size].to_i > 0 ? cfg[:max_message_size].to_i : 8

  @aws_url="#{@protocol}://#{@host}"

  @cache_queue_list = cfg[:cache_queue_list].nil? ? true : cfg[:cache_queue_list]
  @reliable =         cfg[:reliable].nil?         ? true : cfg[:reliable]

  #initialize the subscriptions and queues
  @subscriptions = {}
  @queues_by_priority = {}
  @current_subscription = 0
  queues
end

Instance Attribute Details

#access_key_id ⇒ Object

configurable params



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# File 'lib/activemessaging/adapters/asqs.rb', line 27

def access_key_id
  @access_key_id
end

#aws_version ⇒ Object

configurable params



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# File 'lib/activemessaging/adapters/asqs.rb', line 27

def aws_version
  @aws_version
end

#cache_queue_list ⇒ Object

configurable params



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# File 'lib/activemessaging/adapters/asqs.rb', line 27

def cache_queue_list
  @cache_queue_list
end

#content_type ⇒ Object

configurable params



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# File 'lib/activemessaging/adapters/asqs.rb', line 27

def content_type
  @content_type
end

#host ⇒ Object

configurable params



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# File 'lib/activemessaging/adapters/asqs.rb', line 27

def host
  @host
end

#max_message_size ⇒ Object

configurable params



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# File 'lib/activemessaging/adapters/asqs.rb', line 27

def max_message_size
  @max_message_size
end

#poll_interval ⇒ Object

configurable params



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# File 'lib/activemessaging/adapters/asqs.rb', line 27

def poll_interval
  @poll_interval
end

#port ⇒ Object

configurable params



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# File 'lib/activemessaging/adapters/asqs.rb', line 27

def port
  @port
end

#reconnect_delay ⇒ Object

configurable params



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# File 'lib/activemessaging/adapters/asqs.rb', line 27

def reconnect_delay
  @reconnect_delay
end

#secret_access_key ⇒ Object

configurable params



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# File 'lib/activemessaging/adapters/asqs.rb', line 27

def secret_access_key
  @secret_access_key
end

Instance Method Details

#disconnect ⇒ Object 



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# File 'lib/activemessaging/adapters/asqs.rb', line 60

def disconnect
  #it's an http request - there is no disconnect - ha!
  return true
end

#receive(options = {}) ⇒ Object

new receive respects priorities



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# File 'lib/activemessaging/adapters/asqs.rb', line 115

def receive(options={})
  message = nil

  only_priorities = options[:priorities]

  # loop through the priorities
  @queues_by_priority.keys.sort.each do |priority|

    # skip this priority if there is a list, and it is not in the list
    next if only_priorities && !only_priorities.include?(priority.to_i)

    # puts " - priority: #{priority}"
    # loop through queues for the priority in random order each time
    @queues_by_priority[priority].shuffle.each do |queue_name|
      # puts "   - queue_name: #{queue_name}"
      queue = queues[queue_name]
      subscription = @subscriptions[queue_name]

      next if queue.nil? || subscription.nil?
      messages = retrieve_messsages(queue, 1, subscription.headers[:visibility_timeout])

      if (messages && !messages.empty?)
        message = messages[0]
      end

      break if message
    end

    break if message
  end

  # puts " - message: #{message}"
  message
end

#received(message, headers = {}) ⇒ Object

# receive a single message from any of the subscribed queues # check each queue once, then sleep for poll_interval def receive

raise "No subscriptions to receive messages from." if (@subscriptions.nil? || @subscriptions.empty?)
start = @current_subscription
while true
  # puts "calling receive..."
  @current_subscription = ((@current_subscription < @subscriptions.length-1) ? @current_subscription + 1 : 0)
  sleep poll_interval if (@current_subscription == start)
  queue_name = @subscriptions.keys.sort[@current_subscription]
  queue = queues[queue_name]
  subscription = @subscriptions[queue_name]
  unless queue.nil?
    messages = retrieve_messsages queue, 1, subscription.headers[:visibility_timeout]
    return messages[0] unless (messages.nil? or messages.empty? or messages[0].nil?)
  end
end

end



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# File 'lib/activemessaging/adapters/asqs.rb', line 169

def received message, headers={}
  begin
    delete_message message
  rescue Object=>exception
    logger.error "Exception in ActiveMessaging::Adapters::AmazonSWS::Connection.received() logged and ignored: "
    logger.error exception
  end
end

#send(queue_name, message_body, message_headers = {}) ⇒ Object

queue_name string, body string, headers hash send a single message to a queue



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# File 'lib/activemessaging/adapters/asqs.rb', line 95

def send queue_name, message_body, message_headers={}
  queue = get_or_create_queue queue_name
  send_messsage queue, message_body
end

#subscribe(queue_name, message_headers = {}) ⇒ Object

queue_name string, headers hash for sqs, make sure queue exists, if not create, then add to list of polled queues



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# File 'lib/activemessaging/adapters/asqs.rb', line 67

def subscribe queue_name, message_headers={}
  # look at the existing queues, create any that are missing
  queue = get_or_create_queue queue_name
  if @subscriptions.has_key? queue.name
    @subscriptions[queue.name].add
  else
    @subscriptions[queue.name] = Subscription.new(queue.name, message_headers)
  end
  priority = @subscriptions[queue.name].priority

  @queues_by_priority[priority] = [] unless @queues_by_priority.has_key?(priority)
  @queues_by_priority[priority] << queue.name unless @queues_by_priority[priority].include?(queue.name)
end

#unreceive(message, headers = {}) ⇒ Object

do nothing; by not deleting the message will eventually become visible again



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# File 'lib/activemessaging/adapters/asqs.rb', line 179

def unreceive message, headers={}
  return true
end

#unsubscribe(queue_name, message_headers = {}) ⇒ Object

queue_name string, headers hash for sqs, attempt delete the queues, won’t work if not empty, that’s ok



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# File 'lib/activemessaging/adapters/asqs.rb', line 83

def unsubscribe queue_name, message_headers={}
  if @subscriptions[queue_name]
    @subscriptions[queue_name].remove
    if @subscriptions[queue_name].count <= 0
      sub = @subscriptions.delete(queue_name)
      @queues_by_priority[sub.priority].delete(queue_name)
    end
  end
end