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Module: AWS::Core::LazyErrorClasses

Included in:
AutoScaling::Errors, AWS::CloudFormation::Errors, AWS::CloudFront::Errors, AWS::CloudSearch::Errors, AWS::CloudTrail::Errors, AWS::CloudWatch::Errors, DataPipeline::Errors, DynamoDB::Errors, EC2::Errors, ELB::Errors, EMR::Errors, ElastiCache::Errors, ElasticBeanstalk::Errors, ElasticTranscoder::Errors, Glacier::Errors, IAM::Errors, ImportExport::Errors, Kinesis::Errors, OpsWorks::Errors, RDS::Errors, Redshift::Errors, Route53::Errors, S3::Errors, SNS::Errors, SQS::Errors, STS::Errors, SimpleEmailService::Errors, SimpleWorkflow::Errors, StorageGateway::Errors, Support::Errors
Defined in:
lib/aws/core/lazy_error_classes.rb

Overview

Provides lazy creation of error classes via #const_missing.

Extend this module provides 3 benefits to another module:

  • A method that accepts strings and returns error classes.
  • Thread-safe dynamic error class creation via #const_missing
  • An error grammar for parsing AWS xml errors

Here is an example of how it works:

Class Foo
  module Errors
    extend AWS::Core::LazyErrorClasses
  end
end

Foo::Errors.error_class('NoSuchKey')
#=> Foo::Errors::NoSuckKey

Foo::Errors.error_class('Nested.Error.Klasses')
#=> Foo::Errors::Nested::Error::Klasses

The errors returned from #error_class are subclasses of Errors::Base.

Constant Summary

BASE_ERROR_GRAMMAR =

This grammar parses the defualt AWS XML error format

XML::Grammar.customize do
  element("Error") do
    ignore
  end
end

Instance Method Summary collapse

Instance Method Details

#const_missing(constant) ⇒ nil

Defines a new error class.

Parameters:

  • constant (String, Symbol)

Returns:

  • (nil) 


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# File 'lib/aws/core/lazy_error_classes.rb', line 68

def const_missing constant
  const_missing_mutex.synchronize do
    # It's possible the constant was defined by another thread while
    # this thread was waiting on the mutex, check before setting.
    if error_const_set?(constant)
      const_get(constant)
    else
      const_set(constant, Class.new(Errors::Base) { extend LazyErrorClasses })
    end
  end
end

#error_class(code) ⇒ Class

Converts the error code into an error class constant.

AWS::EC2::Errors.error_class('Non.Existent.Error')
#=> AWS::EC2::Errors::Non::Existent::Error

Parameters:

  • code (String) —

    An AWS error code.

Returns:

  • (Class) —

    Returns the error class defiend by the error code.



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# File 'lib/aws/core/lazy_error_classes.rb', line 89

def error_class code
  module_eval("#{self}::#{code.gsub('.Range','Range').gsub(".","::")}")
end