Class: Aws::SqsInterface

Inherits:
AwsBase show all
Includes:
AwsBaseInterface
Defined in:
lib/sqs/right_sqs_interface.rb

Overview

Right::Aws::SqsInterface - RightScale’s low-level Amazon SQS interface for API version 2008-01-01 and later. For explanations of the semantics of each call, please refer to Amazon’s documentation at developer.amazonwebservices.com/connect/kbcategory.jspa?categoryID=31

This class provides a procedural interface to SQS. Conceptually it is mostly a pass-through interface to SQS and its API is very similar to the bare SQS API. For a somewhat higher-level and object-oriented interface, see Aws::Sqs.

Defined Under Namespace

Classes: SqsCreateQueueParser, SqsGetQueueAttributesParser, SqsListQueuesParser, SqsReceiveMessageParser, SqsSendMessagesParser, SqsStatusParser

Constant Summary collapse

API_VERSION = 
"2009-02-01"
DEFAULT_HOST = 
"queue.amazonaws.com"
DEFAULT_PORT = 
443
DEFAULT_PROTOCOL = 
'https'
REQUEST_TTL = 
30
DEFAULT_VISIBILITY_TIMEOUT = 
30
@@bench = 
AwsBenchmarkingBlock.new
@@api = 
API_VERSION

Constants included from AwsBaseInterface

AwsBaseInterface::DEFAULT_SIGNATURE_VERSION

Constants inherited from AwsBase

AwsBase::AMAZON_PROBLEMS

Instance Attribute Summary

Attributes included from AwsBaseInterface

#aws_access_key_id, #cache, #connection, #last_errors, #last_request, #last_request_id, #last_response, #logger, #params, #signature_version

Class Method Summary collapse

Instance Method Summary collapse

Methods included from AwsBaseInterface

#cache_hits?, caching, caching=, #caching?, #close_conn, #generate_request2, #get_conn, #hash_params, #init, #multi_thread, #on_exception, #request_cache_or_info, #request_info2, #request_info_impl, #request_info_xml_simple, #signed_service_params, #symbolize, #update_cache

Methods inherited from AwsBase

amazon_problems, amazon_problems=

Constructor Details

#initialize(aws_access_key_id = nil, aws_secret_access_key = nil, params = {}) ⇒ SqsInterface

Creates a new SqsInterface instance. This instance is limited to operations on SQS objects created with Amazon’s 2008-01-01 API version. This interface will not work on objects created with prior API versions. See Amazon’s article “Migrating to Amazon SQS API version 2008-01-01” at: developer.amazonwebservices.com/connect/entry.jspa?externalID=1148

sqs = Aws::SqsInterface.new('1E3GDYEOGFJPIT75KDT40','hgTHt68JY07JKUY08ftHYtERkjgtfERn57DFE379', {:multi_thread => true, :logger => Logger.new('/tmp/x.log')})

Params is a hash:

{:server       => 'queue.amazonaws.com' # Amazon service host: 'queue.amazonaws.com' (default)
 :port         => 443                   # Amazon service port: 80 or 443 (default)
 :multi_thread => true|false            # Multi-threaded (connection per each thread): true or false (default)
 :signature_version => '0'              # The signature version : '0' or '1'(default)
 :logger       => Logger Object}        # Logger instance: logs to STDOUT if omitted }



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# File 'lib/sqs/right_sqs_interface.rb', line 78

def initialize(aws_access_key_id=nil, aws_secret_access_key=nil, params={})
  init({ :name             => 'SQS',
         :default_host     => ENV['SQS_URL'] ? URI.parse(ENV['SQS_URL']).host   : DEFAULT_HOST,
         :default_port     => ENV['SQS_URL'] ? URI.parse(ENV['SQS_URL']).port   : DEFAULT_PORT,
         :default_protocol => ENV['SQS_URL'] ? URI.parse(ENV['SQS_URL']).scheme : DEFAULT_PROTOCOL,
        :api_version => API_VERSION },
       aws_access_key_id     || ENV['AWS_ACCESS_KEY_ID'],
       aws_secret_access_key || ENV['AWS_SECRET_ACCESS_KEY'],
       params)
end

Class Method Details

.api ⇒ Object 



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# File 'lib/sqs/right_sqs_interface.rb', line 58

def self.api
  @@api
end

.bench_sqs ⇒ Object 



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# File 'lib/sqs/right_sqs_interface.rb', line 53

def self.bench_sqs
  @@bench.service
end

.bench_xml ⇒ Object 



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# File 'lib/sqs/right_sqs_interface.rb', line 50

def self.bench_xml
  @@bench.xml
end

.queue_name_by_url(queue_url) ⇒ Object

Returns short queue name by url.

RightSqs.queue_name_by_url('http://queue.amazonaws.com/ZZ7XXXYYYBINS/my_awesome_queue') #=> 'my_awesome_queue'



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# File 'lib/sqs/right_sqs_interface.rb', line 302

def self.queue_name_by_url(queue_url)
  queue_url[/[^\/]*$/]
rescue
  on_exception
end

Instance Method Details

#clear_queue(queue_url) ⇒ Object

Removes all visible messages from queue. Return true or an exception.

sqs.clear_queue('http://queue.amazonaws.com/ZZ7XXXYYYBINS/my_awesome_queue') #=> true



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# File 'lib/sqs/right_sqs_interface.rb', line 332

def clear_queue(queue_url)
  while (pop_messages(queue_url, 10).length > 0) ; end   # delete all messages in queue
  true
rescue
  on_exception
end

#create_queue(queue_name, default_visibility_timeout = nil) ⇒ Object

Creates a new queue, returning its URI.

sqs.create_queue('my_awesome_queue') #=> 'http://queue.amazonaws.com/ZZ7XXXYYYBINS/my_awesome_queue'



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# File 'lib/sqs/right_sqs_interface.rb', line 154

def create_queue(queue_name, default_visibility_timeout=nil)
  req_hash = generate_request('CreateQueue', 'QueueName' => queue_name,
                              'DefaultVisibilityTimeout' => default_visibility_timeout || DEFAULT_VISIBILITY_TIMEOUT )
  request_info(req_hash, SqsCreateQueueParser.new(:logger => @logger))
rescue
  on_exception
end

#delete_message(queue_url, receipt_handle) ⇒ Object

Deletes message from queue. Returns true or an exception. Amazon returns true on deletion of non-existent messages. You must use the receipt handle for a message to delete it, not the message ID.

From the SQS Developer Guide: “It is possible you will receive a message even after you have deleted it. This might happen on rare occasions if one of the servers storing a copy of the message is unavailable when you request to delete the message. The copy remains on the server and might be returned to you again on a subsequent receive request. You should create your system to be idempotent so that receiving a particular message more than once is not a problem. ”

sqs.delete_message('http://queue.amazonaws.com/ZZ7XXXYYYBINS/my_awesome_queue', 'Euvo62/1nlIet...ao03hd9Sa0w==') #=> true



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# File 'lib/sqs/right_sqs_interface.rb', line 277

def delete_message(queue_url, receipt_handle)
  req_hash = generate_request('DeleteMessage', 'ReceiptHandle' => receipt_handle, :queue_url  => queue_url)
  request_info(req_hash, SqsStatusParser.new(:logger => @logger))
rescue
  on_exception
end

#delete_queue(queue_url) ⇒ Object

Deletes queue. Any messages in the queue are permanently lost. Returns true or an exception. Queue deletion can take up to 60 s to propagate through SQS. Thus, after a deletion, subsequent list_queues calls may still show the deleted queue. It is not unusual within the 60 s window to see the deleted queue absent from one list_queues call but present in the subsequent one. Deletion is eventual.

sqs.delete_queue('http://queue.amazonaws.com/ZZ7XXXYYYBINS/my_awesome_queue_2') #=> true



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# File 'lib/sqs/right_sqs_interface.rb', line 186

def delete_queue(queue_url)
  req_hash = generate_request('DeleteQueue', :queue_url      => queue_url)
  request_info(req_hash, SqsStatusParser.new(:logger => @logger))
rescue
  on_exception
end

#generate_post_request(action, param = {}) ⇒ Object

:nodoc:



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# File 'lib/sqs/right_sqs_interface.rb', line 118

def generate_post_request(action, param={})  # :nodoc:
  service = param[:queue_url] ? URI(param[:queue_url]).path : '/'
  message   = param[:message]                # extract message body if nesessary
  param.each{ |key, value| param.delete(key) if (value.nil? || key.is_a?(Symbol)) }
  service_hash = { "Action"           => action,
                   "Expires"          => (Time.now + REQUEST_TTL).utc.strftime("%Y-%m-%dT%H:%M:%SZ"),
                   "AWSAccessKeyId"   => @aws_access_key_id,
                   "MessageBody"      => message,
                   "Version"          => API_VERSION }
  service_hash.update(param)
  #
  service_params = signed_service_params(@aws_secret_access_key, service_hash, :post, @params[:server], service)
  request        = Net::HTTP::Post.new(AwsUtils::URLencode(service))
  request['Content-Type'] = 'application/x-www-form-urlencoded'
  request.body = service_params
    # prepare output hash
  { :request  => request,
    :server   => @params[:server],
    :port     => @params[:port],
    :protocol => @params[:protocol] }
end

#generate_request(action, param = {}) ⇒ Object

Generates a request hash for the query API



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# File 'lib/sqs/right_sqs_interface.rb', line 95

def generate_request(action, param={})  # :nodoc:
  # For operation requests on a queue, the queue URI will be a parameter,
  # so we first extract it from the call parameters.  Next we remove any
  # parameters with no value or with symbolic keys.  We add the header
  # fields required in all requests, and then the headers passed in as
  # params.  We sort the header fields alphabetically and then generate the
  # signature before URL escaping the resulting query and sending it.
  service = param[:queue_url] ? URI(param[:queue_url]).path : '/'
  param.each{ |key, value| param.delete(key) if (value.nil? || key.is_a?(Symbol)) }
  service_hash = { "Action"           => action,
                   "Expires"          => (Time.now + REQUEST_TTL).utc.strftime("%Y-%m-%dT%H:%M:%SZ"),
                   "AWSAccessKeyId"   => @aws_access_key_id,
                   "Version"          => API_VERSION }
  service_hash.update(param)
  service_params = signed_service_params(@aws_secret_access_key, service_hash, :get, @params[:server], service)
  request        = Net::HTTP::Get.new("#{AwsUtils.URLencode(service)}?#{service_params}")
    # prepare output hash
  { :request  => request,
    :server   => @params[:server],
    :port     => @params[:port],
    :protocol => @params[:protocol] }
end

#get_queue_attributes(queue_url, attribute = 'All') ⇒ Object

Retrieves the queue attribute(s). Returns a hash of attribute(s) or an exception.

sqs.get_queue_attributes('http://queue.amazonaws.com/ZZ7XXXYYYBINS/my_awesome_queue')
#=> {"ApproximateNumberOfMessages"=>"0", "VisibilityTimeout"=>"30"}



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# File 'lib/sqs/right_sqs_interface.rb', line 198

def get_queue_attributes(queue_url, attribute='All')
  req_hash = generate_request('GetQueueAttributes', 'AttributeName' => attribute, :queue_url  => queue_url)
  request_info(req_hash, SqsGetQueueAttributesParser.new(:logger => @logger))
rescue
  on_exception
end

#get_queue_length(queue_url) ⇒ Object

Returns approximate number of messages in queue.

sqs.get_queue_length('http://queue.amazonaws.com/ZZ7XXXYYYBINS/my_awesome_queue') #=> 3



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# File 'lib/sqs/right_sqs_interface.rb', line 322

def get_queue_length(queue_url)
  get_queue_attributes(queue_url)['ApproximateNumberOfMessages'].to_i
rescue
  on_exception
end

#list_queues(queue_name_prefix = nil) ⇒ Object

Lists all queues owned by this user that have names beginning with queue_name_prefix. If queue_name_prefix is omitted then retrieves a list of all queues. Queue creation is an eventual operation and created queues may not show up in immediately subsequent list_queues calls.

sqs.create_queue('my_awesome_queue')
sqs.create_queue('my_awesome_queue_2')
sqs.list_queues('my_awesome') #=> ['http://queue.amazonaws.com/ZZ7XXXYYYBINS/my_awesome_queue','http://queue.amazonaws.com/ZZ7XXXYYYBINS/my_awesome_queue_2']



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# File 'lib/sqs/right_sqs_interface.rb', line 170

def list_queues(queue_name_prefix=nil)
  req_hash = generate_request('ListQueues', 'QueueNamePrefix' => queue_name_prefix)
  request_info(req_hash, SqsListQueuesParser.new(:logger => @logger))
rescue
  on_exception
end

#pop_message(queue_url) ⇒ Object

Pops (retrieves and deletes) first accessible message from queue. Returns the message in format {:id=>'message_id', :body=>'message_body'} or nil.

sqs.pop_message('http://queue.amazonaws.com/ZZ7XXXYYYBINS/my_awesome_queue') #=>
  {:id=>"12345678904GEZX9746N|0N9ED344VK5Z3SV1DTM0|1RVYH4X3TJ0987654321", :body=>"message_1"}



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# File 'lib/sqs/right_sqs_interface.rb', line 360

def pop_message(queue_url)
  messages = pop_messages(queue_url)
  messages.blank? ? nil : messages[0]
rescue
  on_exception
end

#pop_messages(queue_url, number_of_messages = 1) ⇒ Object

Pops (retrieves and deletes) up to ‘number_of_messages’ from queue. Returns an array of retrieved messages in format: [{:id=>'message_id', :body=>'message_body'}].

sqs.pop_messages('http://queue.amazonaws.com/ZZ7XXXYYYBINS/my_awesome_queue', 3) #=>
[{"ReceiptHandle"=>"Euvo62/...+Zw==", "MD5OfBody"=>"16af2...81e3", "Body"=>"Goodbyte World!",
"MessageId"=>"MEZI...JSWDE="}, {...}, ... , {...} ]



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# File 'lib/sqs/right_sqs_interface.rb', line 345

def pop_messages(queue_url, number_of_messages=1)
  messages = receive_message(queue_url, number_of_messages)
  messages.each do |message|
    delete_message(queue_url, message['ReceiptHandle'])
  end
  messages
rescue
  on_exception
end

#queue_name_by_url(queue_url) ⇒ Object

Returns short queue name by url.

sqs.queue_name_by_url('http://queue.amazonaws.com/ZZ7XXXYYYBINS/my_awesome_queue') #=> 'my_awesome_queue'



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# File 'lib/sqs/right_sqs_interface.rb', line 312

def queue_name_by_url(queue_url)
  self.class.queue_name_by_url(queue_url)
rescue
  on_exception
end

#queue_url_by_name(queue_name) ⇒ Object

Given the queue’s short name, this call returns the queue URL or nil if queue is not found

sqs.queue_url_by_name('my_awesome_queue') #=> 'http://queue.amazonaws.com/ZZ7XXXYYYBINS/my_awesome_queue'



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# File 'lib/sqs/right_sqs_interface.rb', line 287

def queue_url_by_name(queue_name)
  return queue_name if queue_name.include?('/')
  queue_urls = list_queues(queue_name)
  queue_urls.each do |queue_url|
    return queue_url if queue_name_by_url(queue_url) == queue_name
  end
  nil
rescue
  on_exception
end

#receive_message(queue_url, max_number_of_messages = 1, visibility_timeout = nil) ⇒ Object

Retrieves a list of messages from queue. Returns an array of hashes in format: {:id=>'message_id', body=>'message_body'}

sqs.receive_message('http://queue.amazonaws.com/ZZ7XXXYYYBINS/my_awesome_queue',10, 5) #=>
 [{"ReceiptHandle"=>"Euvo62...kw==", "MD5OfBody"=>"16af2171b5b83cfa35ce254966ba81e3",
   "Body"=>"Goodbyte World!", "MessageId"=>"MUM4WlAyR...pYOTA="}, ..., {}]

Normally this call returns fewer messages than the maximum specified, even if they are available.



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# File 'lib/sqs/right_sqs_interface.rb', line 234

def receive_message(queue_url, max_number_of_messages=1, visibility_timeout=nil)
  return [] if max_number_of_messages == 0
  req_hash = generate_post_request('ReceiveMessage', 'MaxNumberOfMessages'  => max_number_of_messages, 'VisibilityTimeout' => visibility_timeout,
                                   :queue_url          => queue_url )
  request_info(req_hash, SqsReceiveMessageParser.new(:logger => @logger))
rescue
  on_exception
end

#request_info(request, parser) ⇒ Object

Sends request to Amazon and parses the response Raises AwsError if any banana happened



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# File 'lib/sqs/right_sqs_interface.rb', line 143

def request_info(request, parser) # :nodoc:
  thread = @params[:multi_thread] ? Thread.current : Thread.main
  thread[:sqs_connection] ||= Rightscale::HttpConnection.new(:exception => AwsError, :logger => @logger)
  request_info_impl(thread[:sqs_connection], @@bench, request, parser)
end

#send_message(queue_url, message) ⇒ Object Also known as: push_message

Sends a new message to a queue. Message size is limited to 8 KB. If successful, this call returns a hash containing key/value pairs for “MessageId” and “MD5OfMessageBody”:

sqs.send_message('http://queue.amazonaws.com/ZZ7XXXYYYBINS/my_awesome_queue', 'message_1') #=> "1234567890...0987654321"
=> {"MessageId"=>"MEs4M0JKNlRCRTBBSENaMjROTk58QVFRNzNEREhDVFlFOVJDQ1JKNjF8UTdBRllCUlJUMjhKMUI1WDJSWDE=", "MD5OfMessageBody"=>"16af2171b5b83cfa35ce254966ba81e3"}

On failure, send_message raises an exception.



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# File 'lib/sqs/right_sqs_interface.rb', line 253

def send_message(queue_url, message)
  req_hash = generate_post_request('SendMessage', :message  => message, :queue_url => queue_url)
  request_info(req_hash, SqsSendMessagesParser.new(:logger => @logger))
rescue
  on_exception
end

#set_queue_attributes(queue_url, attribute, value) ⇒ Object

Sets queue attribute. Returns true or an exception.

sqs.set_queue_attributes('http://queue.amazonaws.com/ZZ7XXXYYYBINS/my_awesome_queue', "VisibilityTimeout", 10) #=> true

From the SQS Dev Guide: “Currently, you can set only the VisibilityTimeout attribute for a queue… When you change a queue’s attributes, the change can take up to 60 seconds to propagate throughout the SQS system.”

NB: Attribute values may not be immediately available to other queries for some time after an update. See the SQS documentation for semantics, but in general propagation can take up to 60 s.



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# File 'lib/sqs/right_sqs_interface.rb', line 218

def set_queue_attributes(queue_url, attribute, value)
  req_hash = generate_request('SetQueueAttributes', 'Attribute.Name'  => attribute, 'Attribute.Value' => value, :queue_url  => queue_url)
  request_info(req_hash, SqsStatusParser.new(:logger => @logger))
rescue
  on_exception
end