Class: Aws::SqsInterface

Inherits:
AwsBase show all
Includes:
AwsBaseInterface
Defined in:
lib/sqs/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, #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, #close_connection, #connection, #escape_params, #generate_request2, #get_conn, #hash_params, #init, #multi_thread, #on_exception, #request_cache_or_info, #request_info2, #request_info3, #request_info_impl, #request_info_xml_simple, #request_info_xml_simple3, #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 }



89
90
91
92
93
94
95
96
97
98
 
# File 'lib/sqs/sqs_interface.rb', line 89

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 



69
70
71
 
# File 'lib/sqs/sqs_interface.rb', line 69

def self.api
  @@api
end

.bench ⇒ Object 



55
56
57
 
# File 'lib/sqs/sqs_interface.rb', line 55

def self.bench
  @@bench
end

.bench_sqs ⇒ Object 



63
64
65
 
# File 'lib/sqs/sqs_interface.rb', line 63

def self.bench_sqs
  @@bench.service
end

.bench_xml ⇒ Object 



59
60
61
 
# File 'lib/sqs/sqs_interface.rb', line 59

def self.bench_xml
  @@bench.xml
end

.connection_name ⇒ Object 



49
50
51
 
# File 'lib/sqs/sqs_interface.rb', line 49

def self.connection_name
  :sqs_connection
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'



326
327
328
329
330
 
# File 'lib/sqs/sqs_interface.rb', line 326

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

Instance Method Details

#change_message_visibility(queue_url, receipt_handle, visibility_timeout) ⇒ Object

Sets new visibility timeout value for a message identified by “receipt_handle” Check out the Amazon SQS API documentation for further details.



296
297
298
299
300
301
302
303
304
305
306
 
# File 'lib/sqs/sqs_interface.rb', line 296

def change_message_visibility(queue_url, receipt_handle, visibility_timeout)
  req_hash = generate_request(
      "ChangeMessageVisibility",
      "ReceiptHandle"     => receipt_handle,
      "VisibilityTimeout" => visibility_timeout,
      :queue_url          => queue_url
  )
  request_info(req_hash, SqsStatusParser.new(:logger => @logger))
rescue
  on_exception
end

#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



356
357
358
359
360
361
362
 
# File 'lib/sqs/sqs_interface.rb', line 356

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'



164
165
166
167
168
169
170
 
# File 'lib/sqs/sqs_interface.rb', line 164

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



287
288
289
290
291
292
 
# File 'lib/sqs/sqs_interface.rb', line 287

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



196
197
198
199
200
201
 
# File 'lib/sqs/sqs_interface.rb', line 196

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:



129
130
131
132
133
134
135
136
137
138
139
140
141
142
143
144
145
146
147
148
149
 
# File 'lib/sqs/sqs_interface.rb', line 129

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(Utils::URLencode(service))
  request['Content-Type'] = 'application/x-www-form-urlencoded; charset=utf-8'
  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



106
107
108
109
110
111
112
113
114
115
116
117
118
119
120
121
122
123
124
125
126
127
 
# File 'lib/sqs/sqs_interface.rb', line 106

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("#{Utils.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"}



208
209
210
211
212
213
 
# File 'lib/sqs/sqs_interface.rb', line 208

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



346
347
348
349
350
 
# File 'lib/sqs/sqs_interface.rb', line 346

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']



180
181
182
183
184
185
 
# File 'lib/sqs/sqs_interface.rb', line 180

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"}



385
386
387
388
389
390
 
# File 'lib/sqs/sqs_interface.rb', line 385

def pop_message(queue_url)
  messages = pop_messages(queue_url)
  messages.nil? ? 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="}, {...}, ... , {...} ]



370
371
372
373
374
375
376
377
378
 
# File 'lib/sqs/sqs_interface.rb', line 370

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'



336
337
338
339
340
 
# File 'lib/sqs/sqs_interface.rb', line 336

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'



311
312
313
314
315
316
317
318
319
320
 
# File 'lib/sqs/sqs_interface.rb', line 311

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.



244
245
246
247
248
249
250
251
 
# File 'lib/sqs/sqs_interface.rb', line 244

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, options = {}) ⇒ Object

todo: remove this and switch to using request_info2



155
156
157
158
 
# File 'lib/sqs/sqs_interface.rb', line 155

def request_info(request, parser, options={}) # :nodoc:
  conn = get_conn(self.class.connection_name, @params, @logger)
  request_info_impl(conn, @@bench, request, parser, options)
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.



263
264
265
266
267
268
 
# File 'lib/sqs/sqs_interface.rb', line 263

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.



228
229
230
231
232
233
 
# File 'lib/sqs/sqs_interface.rb', line 228

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