Class: Ec2Metadata::Base

Inherits:
Object
  • Object
show all
Defined in:
lib/ec2_metadata/base.rb

Direct Known Subclasses

Revision, Root

Instance Attribute Summary collapse

Instance Method Summary collapse

Constructor Details

#initialize(path, default_child_key = nil) ⇒ Base

Returns a new instance of Base.



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# File 'lib/ec2_metadata/base.rb', line 9

def initialize(path, default_child_key = nil)
  @path = path
  @default_child_key = default_child_key
end

Instance Attribute Details

#default_child_key ⇒ Object (readonly)

Returns the value of attribute default_child_key.



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# File 'lib/ec2_metadata/base.rb', line 7

def default_child_key
  @default_child_key
end

#path ⇒ Object (readonly)

Returns the value of attribute path.



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# File 'lib/ec2_metadata/base.rb', line 6

def path
  @path
end

Instance Method Details

#child_keys ⇒ Object Also known as: keys 



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# File 'lib/ec2_metadata/base.rb', line 18

def child_keys
  unless defined?(@child_keys)
    lines = Ec2Metadata.get("#{path}").split(/$/).map(&:strip)
    if lines.all?{|line| line =~ /^[\w]+\=.*?/}
      @child_keys = []
      @child_names = {}
      lines.each do |line|
        key, name = line.split(/\=/, 2)
        @child_keys << key
        @child_names[key] = name
      end
    else
      @child_keys = lines
    end
  end
  @child_keys
end

#children ⇒ Object 



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# File 'lib/ec2_metadata/base.rb', line 14

def children
  @children ||= {}
end

#default_child ⇒ Object 



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# File 'lib/ec2_metadata/base.rb', line 83

def default_child
  return @default_child if @default_child
  logging("default_child") do
    if default_child_key
      @getting_default_child = true
      begin
        @default_child = get(default_child_key) 
      ensure
        @getting_default_child = false
      end
    end
  end
end

#from_hash(hash) ⇒ Object 



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# File 'lib/ec2_metadata/base.rb', line 106

def from_hash(hash)
  hash = hash.inject({}){|d, (k, v)| d[Ec2Metadata.formalize_key(k)] = v; d}
  @child_keys = hash.keys
  @children = {}
  hash.each do |key, value|
    if value.is_a?(Array)
      idx = 0
      value = value.inject({}){|d, v| d[idx] = v; idx += 1; d}
    end
    if value.is_a?(Hash)
      child = new_child(key)
      @children[key] = child
      child.from_hash(value)
    else
      @children[key] = value
    end
  end
end

#get(child_key) ⇒ Object Also known as: [] 



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# File 'lib/ec2_metadata/base.rb', line 37

def get(child_key)
  logging("#{self.class.name}.get(#{child_key.inspect})") do
    child_key = Ec2Metadata.formalize_key(child_key)
    if children.has_key?(child_key)
      result = children[child_key]
    else
      if is_child_key?(child_key)
        result = is_struct?(child_key) ?
          new_child(child_key) :
          Ec2Metadata.get("#{path}#{child_key}")
      else
        raise NotFoundError, "#{path}#{child_key} not found as default key" if @getting_default_child
        raise NotFoundError, "#{path}#{child_key} not found" unless default_child
        result = default_child.get(child_key)
      end
      children[child_key] = result
    end
    result
  end
end

#is_child_key?(key) ⇒ Boolean

Returns:

  • (Boolean) 


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# File 'lib/ec2_metadata/base.rb', line 59

def is_child_key?(key)
  exp = /^#{key}\/?$/
  child_keys.any?{|child_key| child_key =~ exp}
end

#is_struct?(child_key) ⇒ Boolean

Returns:

  • (Boolean) 


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# File 'lib/ec2_metadata/base.rb', line 64

def is_struct?(child_key)
  k = Ec2Metadata.formalize_key(child_key) << '/'
  child_keys.include?(k) || (defined?(@child_names) && @child_names.keys.include?(child_key))
end

#new_child(child_key) ⇒ Object 



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# File 'lib/ec2_metadata/base.rb', line 69

def new_child(child_key)
  if defined?(@child_names) && (name = @child_names[child_key])
    grandchild = Base.new("#{path}#{child_key}/")
    child = Base.new("#{path}#{child_key}/")
    child.instance_variable_set(:@children, {name => grandchild})
    child.instance_variable_set(:@child_keys, [name])
    child
  else
    Base.new("#{path}#{child_key}/")
  end
end

#to_hash ⇒ Object 



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# File 'lib/ec2_metadata/base.rb', line 97

def to_hash
  keys.inject({}) do |dest, key|
    key = key.sub(/\/$/, '')
    value = get(key)
    dest[key] = value.respond_to?(:to_hash) ? value.to_hash : value
    dest
  end
end