Module: Aws::AwsBaseInterface

Included in:
SqsInterface
Defined in:
lib/awsbase/awsbase.rb

Constant Summary collapse

DEFAULT_SIGNATURE_VERSION = 
'2'
@@caching = 
false

Instance Attribute Summary collapse

Class Method Summary collapse

Instance Method Summary collapse

Instance Attribute Details

#aws_access_key_id ⇒ Object (readonly)

Current aws_access_key_id



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# File 'lib/awsbase/awsbase.rb', line 162

def aws_access_key_id
  @aws_access_key_id
end

#cache ⇒ Object (readonly)

Cache



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# File 'lib/awsbase/awsbase.rb', line 178

def cache
  @cache
end

#connection ⇒ Object (readonly)

HttpConnection instance



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# File 'lib/awsbase/awsbase.rb', line 176

def connection
  @connection
end

#last_errors ⇒ Object

Last AWS errors list (used by AWSErrorHandler)



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# File 'lib/awsbase/awsbase.rb', line 168

def last_errors
  @last_errors
end

#last_request ⇒ Object (readonly)

Last HTTP request object



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# File 'lib/awsbase/awsbase.rb', line 164

def last_request
  @last_request
end

#last_request_id ⇒ Object

Returns Amazons request ID for the latest request



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# File 'lib/awsbase/awsbase.rb', line 170

def last_request_id
  @last_request_id
end

#last_response ⇒ Object (readonly)

Last HTTP response object



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# File 'lib/awsbase/awsbase.rb', line 166

def last_response
  @last_response
end

#logger ⇒ Object

Logger object



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# File 'lib/awsbase/awsbase.rb', line 172

def logger
  @logger
end

#params ⇒ Object

Initial params hash



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# File 'lib/awsbase/awsbase.rb', line 174

def params
  @params
end

#signature_version ⇒ Object (readonly)

Signature version (all services except s3)



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# File 'lib/awsbase/awsbase.rb', line 180

def signature_version
  @signature_version
end

Class Method Details

.caching ⇒ Object 



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# File 'lib/awsbase/awsbase.rb', line 154

def self.caching
  @@caching
end

.caching=(caching) ⇒ Object 



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# File 'lib/awsbase/awsbase.rb', line 157

def self.caching=(caching)
  @@caching = caching
end

Instance Method Details

#cache_hits?(function, response, do_raise = :raise) ⇒ Boolean

Check if the aws function response hits the cache or not. If the cache hits:

  • raises an AwsNoChange exception if do_raise == :raise.

  • returnes parsed response from the cache if it exists or true otherwise.

If the cache miss or the caching is off then returns false.



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# File 'lib/awsbase/awsbase.rb', line 236

def cache_hits?(function, response, do_raise=:raise)
  result = false
  if caching?
    function = function.to_sym
    # get rid of requestId (this bad boy was added for API 2008-08-08+ and it is uniq for every response)
    response = response.sub(%r{<requestId>.+?</requestId>}, '')
    response_md5 =Digest::MD5.hexdigest(response).to_s
    # check for changes
    unless @cache[function] && @cache[function][:response_md5] == response_md5
      # well, the response is new, reset cache data
      update_cache(function, {:response_md5 => response_md5,
                     :timestamp    => Time.now,
                     :hits         => 0,
                     :parsed       => nil})
    else
      # aha, cache hits, update the data and throw an exception if needed
      @cache[function][:hits] += 1
      if do_raise == :raise
        raise(AwsNoChange, "Cache hit: #{function} response has not changed since "+
              "#{@cache[function][:timestamp].strftime('%Y-%m-%d %H:%M:%S')}, "+
              "hits: #{@cache[function][:hits]}.")
      else
        result = @cache[function][:parsed] || true
      end
    end
  end
  result
end

#caching? ⇒ Boolean

Returns true if the describe_xxx responses are being cached



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# File 'lib/awsbase/awsbase.rb', line 227

def caching?
  @params.key?(:cache) ? @params[:cache] : @@caching
end

#init(service_info, aws_access_key_id, aws_secret_access_key, params = {}) ⇒ Object

:nodoc:

Raises:



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# File 'lib/awsbase/awsbase.rb', line 182

def init(service_info, aws_access_key_id, aws_secret_access_key, params={}) #:nodoc:
@params = params
raise AwsError.new("AWS access keys are required to operate on #{service_info[:name]}") \
if aws_access_key_id.blank? || aws_secret_access_key.blank?
  @aws_access_key_id     = aws_access_key_id
  @aws_secret_access_key = aws_secret_access_key
  # if the endpoint was explicitly defined - then use it
  if @params[:endpoint_url]
    @params[:server]   = URI.parse(@params[:endpoint_url]).host
    @params[:port]     = URI.parse(@params[:endpoint_url]).port
    @params[:service]  = URI.parse(@params[:endpoint_url]).path
    @params[:protocol] = URI.parse(@params[:endpoint_url]).scheme
    @params[:region]   = nil
  else
    @params[:server]   ||= service_info[:default_host]
    @params[:server]     = "#{@params[:region]}.#{@params[:server]}" if @params[:region]
    @params[:port]     ||= service_info[:default_port]
    @params[:service]  ||= service_info[:default_service]
    @params[:protocol] ||= service_info[:default_protocol]
  end
  if !@params[:multi_thread].nil? && @params[:connection_mode].nil? # user defined this
    @params[:connection_mode] = @params[:multi_thread] ? :per_thread : :single
  end
  #      @params[:multi_thread] ||= defined?(AWS_DAEMON)
  @params[:connection_mode] ||= :default
  @params[:connection_mode] = :per_request if @params[:connection_mode] == :default
  @logger = @params[:logger]
  @logger = RAILS_DEFAULT_LOGGER if !@logger && defined?(RAILS_DEFAULT_LOGGER)
  @logger = Logger.new(STDOUT)   if !@logger
  @logger.info "New #{self.class.name} using #{@params[:connection_mode].to_s}-connection mode"
  @error_handler = nil
  @cache = {}
  @signature_version = (params[:signature_version] || DEFAULT_SIGNATURE_VERSION).to_s
end

#multi_thread ⇒ Object

Return true if this instance works in multi_thread mode and false otherwise.



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# File 'lib/awsbase/awsbase.rb', line 275

def multi_thread
  @params[:multi_thread]
end

#on_exception(options = {:raise=>true, :log=>true}) ⇒ Object

:nodoc:



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# File 'lib/awsbase/awsbase.rb', line 269

def on_exception(options={:raise=>true, :log=>true}) # :nodoc:
  raise if $!.is_a?(AwsNoChange)
  AwsError::on_aws_exception(self, options)
end

#request_cache_or_info(method, link, parser_class, benchblock, use_cache = true) ⇒ Object

:nodoc:



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# File 'lib/awsbase/awsbase.rb', line 349

def request_cache_or_info(method, link, parser_class, benchblock, use_cache=true) #:nodoc:
  # We do not want to break the logic of parsing hence will use a dummy parser to process all the standard
  # steps (errors checking etc). The dummy parser does nothig - just returns back the params it received.
  # If the caching is enabled and hit then throw  AwsNoChange.
  # P.S. caching works for the whole images list only! (when the list param is blank)
  # check cache
  response, params = request_info(link, DummyParser.new)
  cache_hits?(method.to_sym, response.body) if use_cache
  parser = parser_class.new(:logger => @logger)
  benchblock.xml.add!{ parser.parse(response, params) }
  result = block_given? ? yield(parser) : parser.result
  # update parsed data
  update_cache(method.to_sym, :parsed => result) if use_cache
  result
end

#request_info_impl(connection, benchblock, request, parser, &block) ⇒ Object

:nodoc:



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# File 'lib/awsbase/awsbase.rb', line 279

def request_info_impl(connection, benchblock, request, parser, &block) #:nodoc:
  @connection    = connection
  @last_request  = request[:request]
  @last_response = nil
  response=nil
  blockexception = nil

  if(block != nil)
    # TRB 9/17/07 Careful - because we are passing in blocks, we get a situation where
    # an exception may get thrown in the block body (which is high-level
    # code either here or in the application) but gets caught in the
    # low-level code of HttpConnection.  The solution is not to let any
    # exception escape the block that we pass to HttpConnection::request.
    # Exceptions can originate from code directly in the block, or from user
    # code called in the other block which is passed to response.read_body.
    benchblock.service.add! do
      responsehdr = @connection.request(request) do |response|
        #########
        begin
          @last_response = response
          if response.is_a?(Net::HTTPSuccess)
            @error_handler = nil
            response.read_body(&block)
          else
            @error_handler = AWSErrorHandler.new(self, parser, :errors_list => self.class.amazon_problems) unless @error_handler
            check_result   = @error_handler.check(request)
            if check_result
              @error_handler = nil
              return check_result
            end
            raise AwsError.new(@last_errors, @last_response.code, @last_request_id)
          end
        rescue Exception => e
          blockexception = e
        end
      end
      #########

      #OK, now we are out of the block passed to the lower level
      if(blockexception)
        raise blockexception
      end
      benchblock.xml.add! do
        parser.parse(responsehdr)
      end
      return parser.result
    end
  else
    benchblock.service.add!{ response = @connection.request(request) }
    # check response for errors...
    @last_response = response
    if response.is_a?(Net::HTTPSuccess)
      @error_handler = nil
      benchblock.xml.add! { parser.parse(response) }
      return parser.result
    else
      @error_handler = AWSErrorHandler.new(self, parser, :errors_list => self.class.amazon_problems) unless @error_handler
      check_result   = @error_handler.check(request)
      if check_result
        @error_handler = nil
        return check_result
      end
      raise AwsError.new(@last_errors, @last_response.code, @last_request_id)
    end
  end
rescue
  @error_handler = nil
  raise
end

#signed_service_params(aws_secret_access_key, service_hash, http_verb = nil, host = nil, service = nil) ⇒ Object 



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# File 'lib/awsbase/awsbase.rb', line 217

def signed_service_params(aws_secret_access_key, service_hash, http_verb=nil, host=nil, service=nil )
  case signature_version.to_s
  when '2'
    AwsUtils::sign_request_v2(aws_secret_access_key, service_hash, http_verb, host, service)
  else
    raise AwsError.new("Unknown signature version (#{signature_version.to_s}) requested")
  end
end

#update_cache(function, hash) ⇒ Object 



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# File 'lib/awsbase/awsbase.rb', line 265

def update_cache(function, hash)
  (@cache[function.to_sym] ||= {}).merge!(hash) if caching?
end