Module: CloudFormationDSL::Helpers

Included in:
Template
Defined in:
lib/cloudformation-dsl/helpers.rb

Instance Method Summary collapse

Instance Method Details

#aws_account_id ⇒ Object 



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# File 'lib/cloudformation-dsl/helpers.rb', line 77

def () ref("AWS::AccountId") end

#aws_no_value ⇒ Object 



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# File 'lib/cloudformation-dsl/helpers.rb', line 81

def aws_no_value() ref("AWS::NoValue") end

#aws_notification_arns ⇒ Object 



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# File 'lib/cloudformation-dsl/helpers.rb', line 79

def aws_notification_arns() ref("AWS::NotificationARNs") end

#aws_stack_id ⇒ Object 



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# File 'lib/cloudformation-dsl/helpers.rb', line 83

def aws_stack_id() ref("AWS::StackId") end

#aws_stack_name ⇒ Object 



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# File 'lib/cloudformation-dsl/helpers.rb', line 85

def aws_stack_name() ref("AWS::StackName") end

#base64(value) ⇒ Object

Formation helpers



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# File 'lib/cloudformation-dsl/helpers.rb', line 30

def base64(value) { :'Fn::Base64' => value } end

#equal(one, two) ⇒ Object 



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# File 'lib/cloudformation-dsl/helpers.rb', line 49

def equal(one, two) { :'Fn::Equals' => [one, two] } end

#file(filename) ⇒ Object

Read the specified file and return its value as a string literal



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# File 'lib/cloudformation-dsl/helpers.rb', line 94

def file(filename) File.read(File.absolute_path(filename, File.dirname($PROGRAM_NAME))) end

#find_in_map(map, key, name) ⇒ Object 



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# File 'lib/cloudformation-dsl/helpers.rb', line 17

def find_in_map(map, key, name)
  # Eagerly evaluate mappings when all keys are known at template expansion time
  if map.is_a?(String) && key.is_a?(String) && name.is_a?(String)
    # We don't know whether the map was built with string keys or symbol keys.  Try both.
    def get(map, key) map[key] || map.fetch(key.to_sym) end
    get(get(@dict.fetch(:Mappings).fetch(map), key), name)
  else
    { :'Fn::FindInMap' => [ map, key, name ] }
  end
end

#fn_and(*condition_list) ⇒ Object 



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# File 'lib/cloudformation-dsl/helpers.rb', line 61

def fn_and(*condition_list)
  case condition_list.length
  when 0..1 then raise "fn_and needs at least 2 items."
  when 2..10 then  { :'Fn::And' => condition_list }
  else raise "fn_and needs a list of 2-10 items that evaluate to true/false."
  end
end

#fn_if(cond, if_true, if_false) ⇒ Object 



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# File 'lib/cloudformation-dsl/helpers.rb', line 69

def fn_if(cond, if_true, if_false) { :'Fn::If' => [cond, if_true, if_false] } end

#fn_not(condition) ⇒ Object 



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# File 'lib/cloudformation-dsl/helpers.rb', line 51

def fn_not(condition) { :'Fn::Not' => [condition] } end

#fn_or(*condition_list) ⇒ Object 



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# File 'lib/cloudformation-dsl/helpers.rb', line 53

def fn_or(*condition_list)
  case condition_list.length
  when 0..1 then raise "fn_or needs at least 2 items."
  when 2..10 then  { :'Fn::Or' => condition_list }
  else raise "fn_or needs a list of 2-10 items that evaluate to true/false."
  end
end

#get_att(resource, attribute) ⇒ Object 



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# File 'lib/cloudformation-dsl/helpers.rb', line 34

def get_att(resource, attribute) { :'Fn::GetAtt' => [ resource, attribute ] } end

#get_azs(region = '') ⇒ Object 



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# File 'lib/cloudformation-dsl/helpers.rb', line 36

def get_azs(region = '') { :'Fn::GetAZs' => region } end

#interpolate(string, locals = {}) ⇒ Object

Interpolates a string like “NAME={ref(‘Service’)}” and returns a CloudFormation “Fn::Join” operation to collect the results. Anything between and } is interpreted as a Ruby expression and eval’d. This is especially useful with Ruby “here” documents. Local variables may also be exposed to the string via the locals hash.



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# File 'lib/cloudformation-dsl/helpers.rb', line 100

def interpolate(string, locals={})
  list = []
  while string.length > 0
    head, match, string = string.partition(/\{\{.*?\}\}/)
    list << head if head.length > 0
    list << eval(match[2..-3], nil, 'interpolated string') if match.length > 0
  end

  # Split out strings in an array by newline, for visibility
  list = list.flat_map {|value| value.is_a?(String) ? value.lines.to_a : value }
  join('', *list)
end

#join(delim, *list) ⇒ Object 



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# File 'lib/cloudformation-dsl/helpers.rb', line 38

def join(delim, *list)
  case list.length
  when 0 then ''
  when 1 then list[0]
  else join_list(delim,list)
  end
end

#join_interpolate(delim, string) ⇒ Object 



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# File 'lib/cloudformation-dsl/helpers.rb', line 113

def join_interpolate(delim, string)
  $stderr.puts "join_interpolate(delim,string) has been deprecated; use interpolate(string) instead"
  interpolate(string)
end

#join_list(delim, list) ⇒ Object

Variant of join that matches the native CFN syntax.



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# File 'lib/cloudformation-dsl/helpers.rb', line 47

def join_list(delim, list) { :'Fn::Join' => [ delim, list ] } end

#load_from_file(filename) ⇒ Object 



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# File 'lib/cloudformation-dsl/helpers.rb', line 3

def load_from_file(filename)
  file = File.open(filename)
  # Figure out what the file extension is and process accordingly.
  case File.extname(filename)
  when ".rb"; eval(file.read, nil, filename)
  when ".json"; JSON.load(file)
  when ".yaml"; YAML::load(file)
  else
    raise("Do not recognize extension of #{filename}.")
  end
ensure
  file.close
end

#no_value ⇒ Object

deprecated, for backward compatibility



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# File 'lib/cloudformation-dsl/helpers.rb', line 88

def no_value()
  warn_deprecated('no_value()', 'aws_no_value()')
  aws_no_value()
end

#not_equal(one, two) ⇒ Object 



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# File 'lib/cloudformation-dsl/helpers.rb', line 71

def not_equal(one, two) fn_not(equal(one,two)) end

#ref(name) ⇒ Object 



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# File 'lib/cloudformation-dsl/helpers.rb', line 75

def ref(name) { :Ref => name } end

#select(index, list) ⇒ Object 



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# File 'lib/cloudformation-dsl/helpers.rb', line 73

def select(index, list) { :'Fn::Select' => [ index, list ] } end