Class: Lono::Inspector::Depends

Inherits:
Base
  • Object
show all
Defined in:
lib/lono/inspector/depends.rb

Defined Under Namespace

Classes: Node

Instance Method Summary collapse

Methods inherited from Base

#check_template_exists, #data, #generate_templates, #run

Constructor Details

#initialize(stack_name, options) ⇒ Depends

Returns a new instance of Depends.



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# File 'lib/lono/inspector/depends.rb', line 5

def initialize(stack_name, options)
  super
  @nodes = [] # lookup map
end

Instance Method Details

#check_graphviz_installed ⇒ Object

Check if Graphiz is installed and prints a user friendly message if it is not installed. Provide instructions if on macosx.



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# File 'lib/lono/inspector/depends.rb', line 95

def check_graphviz_installed
  installed = system("type dot > /dev/null") # dot is a command that is part of the graphviz package
  unless installed
    puts "It appears that the Graphviz is not installed.  Please install it to generate the graph."
    if RUBY_PLATFORM =~ /darwin/
      puts "You can install Graphviz with homebrew:"
      puts "  brew install brew install graphviz"
    end
    exit 1
  end
end

#normalize_children(node_list, node) ⇒ Object

It is possible with bad CloudFormation templates that the dependency is not resolved, but we wont deal with that. Users can validate their CloudFormation template before using this tool.



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# File 'lib/lono/inspector/depends.rb', line 55

def normalize_children(node_list, node)
  kids = []
  node.depends_on.each do |dependent_logical_id|
    node = node_list.find { |n| n.name == dependent_logical_id }
    kids << node
  end
  kids
end

#normalize_depends_on(resource) ⇒ Object

normalized DependsOn attribute to an Array of Strings



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# File 'lib/lono/inspector/depends.rb', line 42

def normalize_depends_on(resource)
  dependencies = resource["DependsOn"] || []
  [dependencies].flatten
end

#normalize_resource_type(resource) ⇒ Object 



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# File 'lib/lono/inspector/depends.rb', line 47

def normalize_resource_type(resource)
  type = resource["Type"]
  type.sub("AWS::", "") # strip out AWS to make less verbose
end

#perform ⇒ Object 



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# File 'lib/lono/inspector/depends.rb', line 10

def perform
  puts "Generating dependencies tree..."
  return if @options[:noop]

  # First loop through top level nodes and build set depends_on property
  node_list = [] # top level node list
  resources = data["Resources"]
  resources.each do |logical_id, resource|
    node = Node.new(logical_id)
    node.depends_on = normalize_depends_on(resource)
    node.resource_type = normalize_resource_type(resource)
    node_list << node
  end

  # Now that we have loop through all the top level resources once
  # we can use the depends_on attribute on each node and set the
  # children property since the identity nodes are in memory.
  node_list.each do |node|
    node.children = normalize_children(node_list, node)
  end

  # At this point we have a tree of nodes.
  if @options[:display] == "text"
    puts "CloudFormation Dependencies:"
    node_list.each { |node| print_tree(node) }
  else
    print_graph(node_list)
    puts "CloudFormation Dependencies graph generated."
  end
end

#print_graph(node_list) ⇒ Object 



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# File 'lib/lono/inspector/depends.rb', line 72

def print_graph(node_list)
  check_graphviz_installed
  digraph do
    # graph_attribs << 'size="6,6"'
    node_attribs << lightblue << filled

    node_list.each do |n|
      node(n.graph_name)
      n.children.each do |child|
        edge n.graph_name, child.graph_name
      end
    end

    random = (0...8).map { (65 + rand(26)).chr }.join
    path = "/tmp/cloudformation-depends-on-#{random}"
    save path, "png"
    # Check if open command exists and use it to open the image.
    system "open #{path}.png" if system("type open > /dev/null")
  end
end

#print_tree(node, depth = 0) ⇒ Object 



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# File 'lib/lono/inspector/depends.rb', line 64

def print_tree(node, depth=0)
  spacing = "  " * depth
  puts "#{spacing}#{node.name}"
  node.children.each do |node|
    print_tree(node, depth+1)
  end
end