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#
# Copyright (c) 2007-2008 RightScale Inc
#
# 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.
#
# THE SOFTWARE IS PROVIDED "AS IS", WITHOUT WARRANTY OF ANY KIND,
# EXPRESS OR IMPLIED, INCLUDING BUT NOT LIMITED TO THE WARRANTIES OF
# MERCHANTABILITY, FITNESS FOR A PARTICULAR PURPOSE AND
# NONINFRINGEMENT. IN NO EVENT SHALL THE AUTHORS OR COPYRIGHT HOLDERS BE
# LIABLE FOR ANY CLAIM, DAMAGES OR OTHER LIABILITY, WHETHER IN AN ACTION
# OF CONTRACT, TORT OR OTHERWISE, ARISING FROM, OUT OF OR IN CONNECTION
# WITH THE SOFTWARE OR THE USE OR OTHER DEALINGS IN THE SOFTWARE.
#
module RightAws
#
# = RightAws::Sqs -- RightScale's Amazon SQS interface
# The RightAws::Sqs class provides a complete interface to Amazon's Simple
# Queue Service.
# For explanations of the semantics
# of each call, please refer to Amazon's documentation at
# http://developer.amazonwebservices.com/connect/kbcategory.jspa?categoryID=31
#
# Error handling: all operations raise an RightAws::AwsError in case
# of problems. Note that transient errors are automatically retried.
#
# sqs = RightAws::Sqs.new(aws_access_key_id, aws_secret_access_key)
# queue1 = sqs.queue('my_awesome_queue')
# ...
# queue2 = RightAws::Sqs::Queue.create(sqs, 'my_cool_queue', true)
# puts queue2.size
# ...
# message1 = queue2.receive
# message1.visibility = 0
# puts message1
# ...
# queue2.clear(true)
# queue2.send_message('Ola-la!')
# message2 = queue2.pop
# ...
# grantee1 = RightAws::Sqs::Grantee.create(queue2,'one_cool_guy@email.address')
# grantee1.grant('FULLCONTROL')
# grantee1.drop
# ...
# grantee2 = queue.grantees('another_cool_guy@email.address')
# grantee2.revoke('SENDMESSAGE')
#
# Params is a hash:
#
# {:server => 'queue.amazonaws.com' # Amazon service host: 'queue.amazonaws.com' (default)
# :port => 443 # Amazon service port: 80 or 443 (default)
# :signature_version => '0' # The signature version : '0' or '1'(default)
# :logger => Logger Object} # Logger instance: logs to STDOUT if omitted }
#
class Sqs
attr_reader :interface
def initialize(aws_access_key_id=nil, aws_secret_access_key=nil, params={})
@interface = SqsInterface.new(aws_access_key_id, aws_secret_access_key, params)
end
# Retrieves a list of queues.
# Returns an +array+ of +Queue+ instances.
#
# RightAws::Sqs.queues #=> array of queues
#
def queues(prefix=nil)
@interface.list_queues(prefix).map do |url|
Queue.new(self, url)
end
end
# Returns Queue instance by queue name.
# If the queue does not exist at Amazon SQS and +create+ is true, the method creates it.
#
# RightAws::Sqs.queue('my_awesome_queue') #=> #<RightAws::Sqs::Queue:0xb7b626e4 ... >
#
def queue(queue_name, create=true, visibility=nil)
url = @interface.queue_url_by_name(queue_name)
url = (create ? @interface.create_queue(queue_name, visibility) : nil) unless url
url ? Queue.new(self, url) : nil
end
class Queue
attr_reader :name, :url, :sqs
# Returns Queue instance by queue name.
# If the queue does not exist at Amazon SQS and +create+ is true, the method creates it.
#
# RightAws::Sqs::Queue.create(sqs, 'my_awesome_queue') #=> #<RightAws::Sqs::Queue:0xb7b626e4 ... >
#
def self.create(sqs, url_or_name, create=true, visibility=nil)
sqs.queue(url_or_name, create, visibility)
end
# Creates new Queue instance.
# Does not create a queue at Amazon.
#
# queue = RightAws::Sqs::Queue.new(sqs, 'my_awesome_queue')
#
def initialize(sqs, url_or_name)
@sqs = sqs
@url = @sqs.interface.queue_url_by_name(url_or_name)
@name = @sqs.interface.queue_name_by_url(@url)
end
# Retrieves queue size.
#
# queue.size #=> 1
#
def size
@sqs.interface.get_queue_length(@url)
end
# Clears queue.
# Deletes only the visible messages unless +force+ is +true+.
#
# queue.clear(true) #=> true
#
# P.S. when <tt>force==true</tt> the queue deletes then creates again. This is
# the quickest method to clear a big queue or a queue with 'locked' messages. All queue
# attributes are restored. But there is no way to restore grantees' permissions to
# this queue. If you have no grantees except 'root' then you have no problems.
# Otherwise, it's better to use <tt>queue.clear(false)</tt>.
#
# PS This function is no longer supported. Amazon has changed the SQS semantics to require at least 60 seconds between
# queue deletion and creation. Hence this method will fail with an exception.
#
def clear(force=false)
## if force
## @sqs.interface.force_clear_queue(@url)
## else
@sqs.interface.clear_queue(@url)
## end
end
# Deletes queue.
# Queue must be empty or +force+ must be set to +true+.
# Returns +true+.
#
# queue.delete(true) #=> true
#
def delete(force=false)
@sqs.interface.delete_queue(@url, force)
end
# Sends new message to queue.
# Returns new Message instance that has been sent to queue.
def send_message(message)
message = message.to_s
msg = Message.new(self, @sqs.interface.send_message(@url, message), message)
msg.sent_at = Time.now
msg
end
alias_method :push, :send_message
# Retrieves several messages from queue.
# Returns an array of Message instances.
#
# queue.receive_messages(2,10) #=> array of messages
#
def receive_messages(number_of_messages=1, visibility=nil)
list = @sqs.interface.receive_messages(@url, number_of_messages, visibility)
list.map! do |entry|
msg = Message.new(self, entry[:id], entry[:body], visibility)
msg.received_at = Time.now
msg
end
end
# Retrieves first accessible message from queue.
# Returns Message instance or +nil+ it the queue is empty.
#
# queue.receive #=> #<RightAws::Sqs::Message:0xb7bf0884 ... >
#
def receive(visibility=nil)
list = receive_messages(1, visibility)
list.empty? ? nil : list[0]
end
# Peeks message body.
#
# queue.peek #=> #<RightAws::Sqs::Message:0xb7bf0884 ... >
#
def peek(message_id)
entry = @sqs.interface.peek_message(@url, message_id)
msg = Message.new(self, entry[:id], entry[:body])
msg.received_at = Time.now
msg
end
# Pops (and deletes) first accessible message from queue.
# Returns Message instance or +nil+ it the queue is empty.
#
# queue.pop #=> #<RightAws::Sqs::Message:0xb7bf0884 ... >
#
def pop
msg = receive
msg.delete if msg
msg
end
# Retrieves +VisibilityTimeout+ value for the queue.
# Returns new timeout value.
#
# queue.visibility #=> 30
#
def visibility
@sqs.interface.get_visibility_timeout(@url)
end
# Sets new +VisibilityTimeout+ for the queue.
# Returns new timeout value.
#
# queue.visibility #=> 30
# queue.visibility = 33
# queue.visibility #=> 33
#
def visibility=(visibility_timeout)
@sqs.interface.set_visibility_timeout(@url, visibility_timeout)
visibility_timeout
end
# Sets new queue attribute value.
# Not all attributes may be changed: +ApproximateNumberOfMessages+ (for example) is a read only attribute.
# Returns a value to be assigned to attribute.
#
# queue.set_attribute('VisibilityTimeout', '100') #=> '100'
# queue.get_attribute('VisibilityTimeout') #=> '100'
#
def set_attribute(attribute, value)
@sqs.interface.set_queue_attributes(@url, attribute, value)
value
end
# Retrieves queue attributes.
# At this moment Amazon supports +VisibilityTimeout+ and +ApproximateNumberOfMessages+ only.
# If the name of attribute is set, returns its value. Otherwise, returns a hash of attributes.
#
# queue.get_attribute('VisibilityTimeout') #=> '100'
#
def get_attribute(attribute='All')
attributes = @sqs.interface.get_queue_attributes(@url, attribute)
attribute=='All' ? attributes : attributes[attribute]
end
# Retrieves a list of grantees.
# Returns an +array+ of Grantee instances if the +grantee_email_address+ is unset.
# Otherwise returns a Grantee instance that points to +grantee_email_address+ or +nil+.
#
# grantees = queue.grantees #=> [#<RightAws::Sqs::Grantee:0xb7bf0888 ... >, ...]
# ...
# grantee = queue.grantees('cool_guy@email.address') #=> nil | #<RightAws::Sqs::Grantee:0xb7bf0888 ... >
#
def grantees(grantee_email_address=nil, permission = nil)
hash = @sqs.interface.list_grants(@url, grantee_email_address, permission)
grantees = []
hash.each do |key, value|
grantees << Grantee.new(self, grantee_email_address, key, value[:name], value[:perms])
end
if grantee_email_address
grantees.right_blank? ? nil : grantees.shift
else
grantees
end
end
end
class Message
attr_reader :queue, :id, :body, :visibility
attr_accessor :sent_at, :received_at
def initialize(queue, id=nil, body=nil, visibility=nil)
@queue = queue
@id = id
@body = body
@visibility = visibility
@sent_at = nil
@received_at = nil
end
# Returns +Message+ instance body.
def to_s
@body
end
# Changes +VisibilityTimeout+ for current message.
# Returns new +VisibilityTimeout+ value.
def visibility=(visibility_timeout)
@queue.sqs.interface.change_message_visibility(@queue.url, @id, visibility_timeout)
@visibility = visibility_timeout
end
# Removes message from queue.
# Returns +true+.
def delete
@queue.sqs.interface.delete_message(@queue.url, @id)
end
end
class Grantee
attr_accessor :queue, :id, :name, :perms, :email
# Creates new Grantee instance.
# To create new grantee for queue use:
#
# grantee = Grantee.new(queue, grantee@email.address)
# grantee.grant('FULLCONTROL')
#
def initialize(queue, email=nil, id=nil, name=nil, perms=[])
@queue = queue
@id = id
@name = name
@perms = perms
@email = email
retrieve unless id
end
# Retrieves security information for grantee identified by email.
# Returns +nil+ if the named user has no privileges on this queue, or
# +true+ if perms updated successfully.
def retrieve # :nodoc:
@id = nil
@name = nil
@perms = []
hash = @queue.sqs.interface.list_grants(@queue.url, @email)
return nil if hash.empty?
grantee = hash.shift
@id = grantee[0]
@name = grantee[1][:name]
@perms = grantee[1][:perms]
true
end
# Adds permissions for grantee.
# Permission: 'FULLCONTROL' | 'RECEIVEMESSAGE' | 'SENDMESSAGE'.
# The caller must have set the email instance variable.
def grant(permission=nil)
raise "You can't grant permission without defining a grantee email address!" unless @email
@queue.sqs.interface.add_grant(@queue.url, @email, permission)
retrieve
end
# Revokes permissions for grantee.
# Permission: 'FULLCONTROL' | 'RECEIVEMESSAGE' | 'SENDMESSAGE'.
# Default value is 'FULLCONTROL'.
# User must have +@email+ or +@id+ set.
# Returns +true+.
def revoke(permission='FULLCONTROL')
@queue.sqs.interface.remove_grant(@queue.url, @email || @id, permission)
unless @email # if email is unknown - just remove permission from local perms list...
@perms.delete(permission)
else # ... else retrieve updated information from Amazon
retrieve
end
true
end
# Revokes all permissions for this grantee.
# Returns +true+
def drop
@perms.each do |permission|
@queue.sqs.interface.remove_grant(@queue.url, @email || @id, permission)
end
retrieve
true
end
end
end
end
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