Class: Bosh::Template::EvaluationContext

Inherits:
Object
  • Object
show all
Includes:
PropertyHelper
Defined in:
lib/bosh/template/evaluation_context.rb

Overview

Helper class to evaluate templates. Used by Director, CLI and Agent.

Defined Under Namespace

Classes: ActiveElseBlock, InactiveElseBlock

Instance Attribute Summary collapse

Instance Method Summary collapse

Methods included from PropertyHelper

#copy_property, #lookup_property

Constructor Details

#initialize(spec) ⇒ EvaluationContext

Returns a new instance of EvaluationContext.

Parameters:

  • spec (Hash) —

    Template spec



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# File 'lib/bosh/template/evaluation_context.rb', line 29

def initialize(spec)
  unless spec.is_a?(Hash)
    raise EvaluationFailed,
          'Invalid spec provided for template evaluation context, ' +
              "Hash expected, #{spec.class} given"
  end

  if spec['job'].is_a?(Hash)
    @name = spec['job']['name']
  else
    @name = nil
  end

  @index = spec['index']
  @spec = openstruct(spec)
  @raw_properties = spec['properties'] || {}
  @properties = openstruct(@raw_properties)

  @links = spec['links'] || {}
end

Instance Attribute Details

#index ⇒ Integer (readonly)

Returns Template instance index.

Returns:

  • (Integer) —

    Template instance index



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# File 'lib/bosh/template/evaluation_context.rb', line 17

def index
  @index
end

#name ⇒ String (readonly)

Returns Template name.

Returns:

  • (String) —

    Template name



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# File 'lib/bosh/template/evaluation_context.rb', line 14

def name
  @name
end

#properties ⇒ Hash (readonly)

Returns Template properties.

Returns:

  • (Hash) —

    Template properties



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# File 'lib/bosh/template/evaluation_context.rb', line 20

def properties
  @properties
end

#raw_properties ⇒ Hash (readonly)

Returns Raw template properties (no openstruct).

Returns:

  • (Hash) —

    Raw template properties (no openstruct)



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# File 'lib/bosh/template/evaluation_context.rb', line 23

def raw_properties
  @raw_properties
end

#spec ⇒ Hash (readonly)

Returns Template spec.

Returns:

  • (Hash) —

    Template spec



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# File 'lib/bosh/template/evaluation_context.rb', line 26

def spec
  @spec
end

Instance Method Details

#get_binding ⇒ Binding

Returns Template binding.

Returns:

  • (Binding) —

    Template binding



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# File 'lib/bosh/template/evaluation_context.rb', line 51

def get_binding
  binding.taint
end

#if_p(*names) {|Object| ... } ⇒ Object

Run a block of code if all given properties are defined

Parameters:

  • names (Array<String>) —

    Property names

Yields:

  • (Object) —

    property values



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# File 'lib/bosh/template/evaluation_context.rb', line 104

def if_p(*names)
  values = names.map do |name|
    value = lookup_property(@raw_properties, name)
    return ActiveElseBlock.new(self) if value.nil?
    value
  end

  yield *values
  InactiveElseBlock.new
end

#link(name) ⇒ Object

Raises:



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# File 'lib/bosh/template/evaluation_context.rb', line 94

def link(name)
  result = lookup_property(@links, name)
  return result unless result.nil?

  raise UnknownLink.new(name)
end

#openstruct(object) ⇒ Object

Returns Object representation where all hashes are unrolled into OpenStruct objects. This exists mostly for backward compatibility, as it doesn’t provide good error reporting.

Returns:

  • (Object) —

    Object representation where all hashes are unrolled into OpenStruct objects. This exists mostly for backward compatibility, as it doesn’t provide good error reporting.



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# File 'lib/bosh/template/evaluation_context.rb', line 118

def openstruct(object)
  case object
    when Hash
      mapped = object.inject({}) { |h, (k, v)| h[k] = openstruct(v); h }
      OpenStruct.new(mapped)
    when Array
      object.map { |item| openstruct(item) }
    else
      object
  end
end

#p(name, default_value) ⇒ Object #p(names, default_value) ⇒ Object #p(names) ⇒ Object #p(name) ⇒ Object

Property lookup helper

Overloads:

  • #p(name, default_value) ⇒ Object

    Returns property value or default value if property not set

    Parameters:

    • name (String) —

      Property name

    • default_value (Object) —

      Default value

    Returns:

    • (Object) —

      Property value

  • #p(names, default_value) ⇒ Object

    Returns first property from the list that is set or default value if none of them are set

    Parameters:

    • names (Array<String>) —

      Property names

    • default_value (Object) —

      Default value

    Returns:

    • (Object) —

      Property value

  • #p(names) ⇒ Object

    Looks up first property from the list that is set, raises an error if none of them are set.

    Parameters:

    • names (Array<String>) —

      Property names

    Returns:

    • (Object) —

      Property value

    Raises:

    • (Bosh::Common::UnknownProperty)
  • #p(name) ⇒ Object

    Looks up property and raises an error if it’s not set

    Parameters:

    • name (String) —

      Property name

    Returns:

    • (Object) —

      Property value

    Raises:

    • (Bosh::Common::UnknownProperty)

Raises:



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# File 'lib/bosh/template/evaluation_context.rb', line 82

def p(*args)
  names = Array(args[0])

  names.each do |name|
    result = lookup_property(@raw_properties, name)
    return result unless result.nil?
  end

  return args[1] if args.length == 2
  raise UnknownProperty.new(names)
end