Class: CfnParser

Inherits:
Object
  • Object
show all
Defined in:
lib/cfn-model/parser/cfn_parser.rb

Overview

This class is the heart of the matter. It will take a CloudFormation template and return a CfnModel object to represent the underlying document in a way that is hopefully more convenient for (cfn-nag rule) developers to work with

Instance Method Summary collapse

Instance Method Details

#parse(cloudformation_yml, parameter_values_json = nil, with_line_numbers = false) ⇒ Object

Given raw json/yml CloudFormation template, returns a CfnModel object or raise ParserErrors if something is amiss with the format



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# File 'lib/cfn-model/parser/cfn_parser.rb', line 39

def parse(cloudformation_yml, parameter_values_json=nil, with_line_numbers=false)
  cfn_model = parse_without_parameters(cloudformation_yml, with_line_numbers)

  apply_parameter_values(cfn_model, parameter_values_json)

  cfn_model
end

#parse_with_line_numbers(cloudformation_yml) ⇒ Object 



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# File 'lib/cfn-model/parser/cfn_parser.rb', line 47

def parse_with_line_numbers(cloudformation_yml)
  handler = LineNumberHandler.new
  parser =  Psych::Parser.new(handler)
  handler.parser = parser
  parser.parse(cloudformation_yml)
  ToRubyWithLineNumbers.create.accept(handler.root).first
end

#parse_without_parameters(cloudformation_yml, with_line_numbers = false) ⇒ Object 



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# File 'lib/cfn-model/parser/cfn_parser.rb', line 55

def parse_without_parameters(cloudformation_yml, with_line_numbers=false)
  pre_validate_model cloudformation_yml

  cfn_hash =
    if with_line_numbers
      parse_with_line_numbers(cloudformation_yml)
    else
      YAML.load cloudformation_yml
    end

  # Transform raw resources in template as performed by
  # transforms
  CfnModel::TransformRegistry.instance.perform_transforms cfn_hash

  validate_references cfn_hash

  cfn_model = CfnModel.new
  cfn_model.raw_model = cfn_hash

  # pass 1: wire properties into ModelElement objects
  if with_line_numbers
    transform_hash_into_model_elements_with_numbers cfn_hash, cfn_model
  else
    transform_hash_into_model_elements cfn_hash, cfn_model
  end
  transform_hash_into_parameters cfn_hash, cfn_model

  # pass 2: tie together separate resources only where necessary to make life easier for rule logic
  post_process_resource_model_elements cfn_model

  cfn_model
end