Class: RightAws::AWSErrorHandler

Inherits:
Object
  • Object
show all
Defined in:
lib/awsbase/right_awsbase.rb

Constant Summary collapse

DEFAULT_CLOSE_ON_4XX_PROBABILITY =

0-100 (%)

10
@@reiteration_start_delay = 
0.2
@@reiteration_time = 
5
@@close_on_error = 
true
@@close_on_4xx_probability = 
DEFAULT_CLOSE_ON_4XX_PROBABILITY

Class Method Summary collapse

Instance Method Summary collapse

Constructor Details

#initialize(aws, parser, params = {}) ⇒ AWSErrorHandler

params: 

:reiteration_time 
:errors_list 
:close_on_error           = true | false 
:close_on_4xx_probability = 1-100



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# File 'lib/awsbase/right_awsbase.rb', line 834

def initialize(aws, parser, params={}) #:nodoc:     
  @aws           = aws              # Link to RightEc2 | RightSqs | RightS3 instance
  @parser        = parser           # parser to parse Amazon response
  @started_at    = Time.now
  @stop_at       = @started_at  + (params[:reiteration_time] || @@reiteration_time) 
  @errors_list   = params[:errors_list] || [] 
  @reiteration_delay = @@reiteration_start_delay
  @retries       = 0
  # close current HTTP(S) connection on 5xx, errors from list and 4xx errors 
  @close_on_error           = params[:close_on_error].nil? ? @@close_on_error : params[:close_on_error]
  @close_on_4xx_probability = params[:close_on_4xx_probability] || @@close_on_4xx_probability       
end

Class Method Details

.close_on_4xx_probability ⇒ Object 



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# File 'lib/awsbase/right_awsbase.rb', line 822

def self.close_on_4xx_probability 
  @@close_on_4xx_probability 
end

.close_on_4xx_probability=(close_on_4xx_probability) ⇒ Object 



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# File 'lib/awsbase/right_awsbase.rb', line 825

def self.close_on_4xx_probability=(close_on_4xx_probability) 
  @@close_on_4xx_probability = close_on_4xx_probability 
end

.close_on_error ⇒ Object 



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# File 'lib/awsbase/right_awsbase.rb', line 814

def self.close_on_error 
  @@close_on_error 
end

.close_on_error=(close_on_error) ⇒ Object 



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# File 'lib/awsbase/right_awsbase.rb', line 817

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

.reiteration_start_delay ⇒ Object 



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# File 'lib/awsbase/right_awsbase.rb', line 798

def self.reiteration_start_delay
  @@reiteration_start_delay
end

.reiteration_start_delay=(reiteration_start_delay) ⇒ Object 



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# File 'lib/awsbase/right_awsbase.rb', line 801

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

.reiteration_time ⇒ Object 



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# File 'lib/awsbase/right_awsbase.rb', line 806

def self.reiteration_time
  @@reiteration_time
end

.reiteration_time=(reiteration_time) ⇒ Object 



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# File 'lib/awsbase/right_awsbase.rb', line 809

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

Instance Method Details

#check(request) ⇒ Object

Returns false if



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# File 'lib/awsbase/right_awsbase.rb', line 848

def check(request)  #:nodoc:
  result           = false
  error_found      = false
  redirect_detected= false
  error_match      = nil
  last_errors_text = ''
  response         = @aws.last_response
  # log error
  request_text_data = "#{request[:protocol]}://#{request[:server]}:#{request[:port]}#{request[:request].path}"
  # is this a redirect?
  # yes!
  if response.is_a?(Net::HTTPRedirection)
    redirect_detected = true 
  else
    # no, it's an error ...
    @aws.logger.warn("##### #{@aws.class.name} returned an error: #{response.code} #{response.message}\n#{response.body} #####")
    @aws.logger.warn("##### #{@aws.class.name} request: #{request_text_data} ####")
  end

  # Extract error/redirection message from the response body
  # Amazon claims that a redirection must have a body but somethimes it is nil....
  if response.body && response.body[/^(<\?xml|<ErrorResponse)/]
    error_parser = RightErrorResponseParser.new
    @aws.class.bench_xml.add! do
      error_parser.parse(response.body)
    end
    @aws.last_errors     = error_parser.errors
    @aws.last_request_id = error_parser.requestID
    last_errors_text     = @aws.last_errors.flatten.join("\n")
  else
    @aws.last_errors     = [[response.code, "#{response.message} (#{request_text_data})"]]
    @aws.last_request_id = '-undefined-'
    last_errors_text     = response.message
  end
  
  # Ok, it is a redirect, find the new destination location
  if redirect_detected
    location = response['location']
    # As for 301 ( Moved Permanently) Amazon does not return a 'Location' header but
    # it is possible to extract a new endpoint from the response body
    if location.right_blank? && response.code=='301' && response.body
      new_endpoint = response.body[/<Endpoint>(.*?)<\/Endpoint>/] && $1
      location     = "#{request[:protocol]}://#{new_endpoint}:#{request[:port]}#{request[:request].path}"
    end
    # ... log information and ...
    @aws.logger.info("##### #{@aws.class.name} redirect requested: #{response.code} #{response.message} #####")
    @aws.logger.info("      Old location: #{request_text_data}")
    @aws.logger.info("      New location: #{location}")
    @aws.logger.info("      Request Verb: #{request[:request].class.name}")
    # ... fix the connection data
    request[:server]   = URI.parse(location).host
    request[:protocol] = URI.parse(location).scheme
    request[:port]     = URI.parse(location).port
  else
    # Not a redirect but an error: try to find the error in our list
    @errors_list.each do |error_to_find|
      if last_errors_text[/#{error_to_find}/i]
        error_found = true
        error_match = error_to_find
        @aws.logger.warn("##### Retry is needed, error pattern match: #{error_to_find} #####")
        break
      end
    end
  end
  
    # check the time has gone from the first error come
  if redirect_detected || error_found
    # Close the connection to the server and recreate a new one. 
    # It may have a chance that one server is a semi-down and reconnection 
    # will help us to connect to the other server 
    if !redirect_detected && @close_on_error
      @aws.destroy_connection(request, "#{self.class.name}: error match to pattern '#{error_match}'")
    end 
             
    if (Time.now < @stop_at)
      @retries += 1
      unless redirect_detected
        @aws.logger.warn("##### Retry ##{@retries} is being performed. Sleeping for #{@reiteration_delay} sec. Whole time: #{Time.now-@started_at} sec ####")
        sleep @reiteration_delay 
        @reiteration_delay *= 2

        # Always make sure that the fp is set to point to the beginning(?)
        # of the File/IO. TODO: it assumes that offset is 0, which is bad.
        if(request[:request].body_stream && request[:request].body_stream.respond_to?(:pos))
          begin
            request[:request].body_stream.pos = 0
          rescue Exception => e
            @logger.warn("Retry may fail due to unable to reset the file pointer" +
                         " -- #{self.class.name} : #{e.inspect}")
          end
        end
      else
        @aws.logger.info("##### Retry ##{@retries} is being performed due to a redirect.  ####")
      end
      result = @aws.request_info(request, @parser)
    else
      @aws.logger.warn("##### Ooops, time is over... ####")
    end 
  # aha, this is unhandled error: 
  elsif @close_on_error 
    # On 5xx(Server errors), 403(RequestTimeTooSkewed) and 408(Request Timeout) a conection has to be closed
    if @aws.last_response.code.to_s[/^(5\d\d|403|408)$/]
      @aws.destroy_connection(request, "#{self.class.name}: code: #{@aws.last_response.code}: '#{@aws.last_response.message}'")
    # Is this a 4xx error ? 
    elsif @aws.last_response.code.to_s[/^4\d\d$/] && @close_on_4xx_probability > rand(100) 
      @aws.destroy_connection(request, "#{self.class.name}: code: #{@aws.last_response.code}: '#{@aws.last_response.message}', " +
                                       "probability: #{@close_on_4xx_probability}%")
    end
  end
  result
end