Class: Jets::Cfn::Resource::Replacer

Inherits:
Object
  • Object
show all
Extended by:
Memoist
Defined in:
lib/jets/cfn/resource/replacer.rb

Instance Method Summary collapse

Constructor Details

#initialize(replacements = {}) ⇒ Replacer

Returns a new instance of Replacer.



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# File 'lib/jets/cfn/resource/replacer.rb', line 5

def initialize(replacements = {})
  @replacements = replacements
end

Instance Method Details

#principal_map(type) ⇒ Object

The principal_map related methods are used by Resource::Lambda::Permission Examples:

"AWS::Events::Rule" => "events.amazonaws.com",
"AWS::Config::ConfigRule" => "config.amazonaws.com",
"AWS::ApiGateway::Method" => "apigateway.amazonaws.com"



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# File 'lib/jets/cfn/resource/replacer.rb', line 60

def principal_map(type)
  service = type.split("::")[1].downcase
  service = special_principal_map(service)
  "#{service}.amazonaws.com"
end

#replace_placeholders(attributes) ⇒ Object

Replace placeholder hash values with replacements. This does a deep replacement to the hash values. The replacement “key” is the string value within the value.

Example:

attributes = {whatever: "foo REPLACE_KEY bar" }
replace_placeholders(attributes, REPLACE_KEY: "blah:arn")
=> {whatever: "foo blah:arn bar" }

Also, we always replace the special namespace value in the hash values. Example:

attributes = {whatever: "{namespace}LambdaFunction" }
replace_placeholders(attributes, {})
=> {whatever: "foo PostsControllerIndexLambdaFunction bar" }



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# File 'lib/jets/cfn/resource/replacer.rb', line 24

def replace_placeholders(attributes)
  update_values(attributes)
end

#replace_value(value) ⇒ Object 



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# File 'lib/jets/cfn/resource/replacer.rb', line 42

def replace_value(value)
  # Dont perform replacement on Integers
  return value if value.is_a?(Integer)
  # return value unless value.is_a?(String) or value.is_a?(Symbol)

  value = value.to_s # normalize to String
  @replacements.each do |k, v|
    # IE: Replaces {namespace} => SecurityJobCheck
    value = value.gsub("{#{k}}", v)
  end
  value
end

#source_arn_map(type) ⇒ Object

From AWS docs: amzn.to/2N0QXQL source_arn is “not supported by all event sources”

When it is not available the resource definition should add it.



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# File 'lib/jets/cfn/resource/replacer.rb', line 77

def source_arn_map(type)
  map = {
    "AWS::ApiGateway::Method" => "!Sub arn:aws:execute-api:${AWS::Region}:${AWS::AccountId}:${RestApi}/*/*"
  }
  map[type.to_s]
end

#special_principal_map(service) ⇒ Object 



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# File 'lib/jets/cfn/resource/replacer.rb', line 66

def special_principal_map(service)
  # special map
  # s3_event actually uses sns topic events to trigger a Lambda function
  map = {s3: "sns"}
  map[service.to_sym] || service
end

#update_values(original) ⇒ Object 



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# File 'lib/jets/cfn/resource/replacer.rb', line 28

def update_values(original)
  case original
  when Array
    original.map { |v| update_values(v) }
  when Hash
    initializer = original.map do |k, v|
      [k, update_values(v)]
    end
    Hash[initializer]
  else
    replace_value(original)
  end
end