Class: Lono::Param::Generator

Inherits:
Object
  • Object
show all
Includes:
Blueprint::Root, Conventions
Defined in:
lib/lono/param/generator.rb

Instance Attribute Summary collapse

Instance Method Summary collapse

Methods included from Conventions

#template_param_convention

Methods included from Blueprint::Root

#bundler_groups, #find_blueprint_root, #require_bundle_gems, #set_blueprint_root

Constructor Details

#initialize(blueprint, options = {}) ⇒ Generator

Returns a new instance of Generator.



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# File 'lib/lono/param/generator.rb', line 6

def initialize(blueprint, options={})
  @blueprint, @options = blueprint, options
  set_blueprint_root(@blueprint)
  @template, @param = template_param_convention(options)
end

Instance Attribute Details

#base_path ⇒ Object (readonly)

set when generate is called



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# File 'lib/lono/param/generator.rb', line 5

def base_path
  @base_path
end

#env_path ⇒ Object (readonly)

set when generate is called



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# File 'lib/lono/param/generator.rb', line 5

def env_path
  @env_path
end

Instance Method Details

#context ⇒ Object

Context for ERB rendering. This is where we control what references get passed to the ERB rendering.



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# File 'lib/lono/param/generator.rb', line 149

def context
  @context ||= Lono::Template::Context.new(@blueprint, @options)
end

#convert_to_cfn_format(contents, casing = :camel) ⇒ Object 



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# File 'lib/lono/param/generator.rb', line 164

def convert_to_cfn_format(contents, casing=:camel)
  lines = parse_contents(contents)

  # First use a Hash structure so that overlay env files will override
  # the base param file.
  data = {}
  lines.each do |line|
    key,value = line.strip.split("=").map {|x| x.strip}
    data[key] = value
  end

  # Now build up the aws json format for parameters
  params = []
  data.each do |key,value|
    param = if value == "use_previous_value"
              {
                "ParameterKey": key,
                "UsePreviousValue": true
              }
            elsif value
              {
                "ParameterKey": key,
                "ParameterValue": value
              }
            end
    if param
      param = param.to_snake_keys if casing == :underscore
      params << param
    end
  end
  params
end

#generate ⇒ Object 



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# File 'lib/lono/param/generator.rb', line 67

def generate
  puts "Generating parameter files for blueprint #{@blueprint.color(:green)}:"

  @base_path, @env_path = lookup_paths

  return unless @base_path || @env_path

  # useful option for lono cfn, since some templates dont require params
  return if @options[:allow_not_exists] && !source_exist?

  if source_exist?
    contents = process_erb
    data = convert_to_cfn_format(contents)
    json = JSON.pretty_generate(data)
    write_output(json)
    unless @options[:mute]
      short_output_path = output_path.sub("#{Lono.root}/","")
      puts "  #{short_output_path}"
    end
  else
    puts "#{@base_path} or #{@env_path} could not be found?  Are you sure it exist?"
    exit 1
  end
  json
end

#lookup_param_file(root: Lono.root, env: Lono.env) ⇒ Object

Lookup precedence:

configs/BLUEPRINT/params/development/TEMPLATE/PARAM.txt
configs/BLUEPRINT/params/development/PARAM.txt
configs/BLUEPRINT/params/development.txt



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# File 'lib/lono/param/generator.rb', line 27

def lookup_param_file(root: Lono.root, env: Lono.env)
  long_form = "#{root}/configs/#{@blueprint}/params/#{env}/#{@template}/#{@param}.txt"
  medium_form = "#{root}/configs/#{@blueprint}/params/#{env}/#{@param}.txt"
  short_form = "#{root}/configs/#{@blueprint}/params/#{env}.txt"

  if ENV['LONO_PARAM_DEBUG']
    puts "Lono.blueprint_root #{Lono.blueprint_root}"
    puts "long_form #{long_form}"
    puts "medium_form #{medium_form}"
    puts "short_form #{short_form}"
  end

  return long_form if File.exist?(long_form) # always consider this first because its so explicit

  # All 3 are the same
  if @blueprint == @template && @template == @param
    return medium_form if File.exist?(medium_form) # higher precedence between longer but short form should be encouraged
    return short_form if File.exist?(short_form)
    return # cannot find a param file
  end

  # Only template and param are the same
  if @template == @param
    return medium_form if File.exist?(medium_form) # only consider medium form
    return # cannot find a param file
  end
end

#lookup_paths ⇒ Object 



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# File 'lib/lono/param/generator.rb', line 55

def lookup_paths
  @base_path = lookup_param_file(env: "base")
  @env_path = lookup_param_file(env: Lono.env)

  if ENV['LONO_PARAM_DEBUG']
    puts "  @base_path #{@base_path.inspect}"
    puts "  @env_path #{@env_path.inspect}"
  end

  [@base_path, @env_path]
end

#output_path ⇒ Object 



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# File 'lib/lono/param/generator.rb', line 197

def output_path
  output = Lono.config.output_path.sub("#{Lono.root}/","")
  path = if @base_path && !@env_path
           # Handle case when base config exist but the env config does not
           @base_path.sub("configs", output).sub("base", Lono.env)
         else
           @env_path.sub("configs", output)
         end
  path.sub(/\.txt$/,'.json')
end

#params(casing = :underscore) ⇒ Object

useful for when calling CloudFormation via the aws-sdk gem



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# File 'lib/lono/param/generator.rb', line 103

def params(casing = :underscore)
  @base_path, @env_path = lookup_paths

  # useful option for lono cfn
  return {} if @options[:allow_not_exists] && !source_exist?

  contents = process_erb
  convert_to_cfn_format(contents, casing)
end

#parse_contents(contents) ⇒ Object 



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# File 'lib/lono/param/generator.rb', line 153

def parse_contents(contents)
  lines = contents.split("\n")
  # remove comment at the end of the line
  lines.map! { |l| l.sub(/#.*/,'').strip }
  # filter out commented lines
  lines = lines.reject { |l| l =~ /(^|\s)#/i }
  # filter out empty lines
  lines = lines.reject { |l| l.strip.empty? }
  lines
end

#process_erb ⇒ Object

Reads both the base source and env source and overlay the two Example 1:

params/base/mystack.txt - base path
params/production/mystack.txt - env path

the base/mystack.txt gets combined with the prod/mystack.txt
it produces a final prod/mystack.txt

Example 2:

params/base/mystack.txt - base path

the base/mystack.txt is used to produced a prod/mystack.txt

Example 3:

params/production/mystack.txt - env path

the prod/mystack.txt is used to produced a prod/mystack.txt



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# File 'lib/lono/param/generator.rb', line 130

def process_erb
  contents = []
  contents << render_erb(@base_path)
  contents << render_erb(@env_path)
  result = contents.compact.join("\n")
  # puts "process_erb result".color(:yellow)
  # puts result
  result
end

#puts_param_message(type) ⇒ Object 



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# File 'lib/lono/param/generator.rb', line 12

def puts_param_message(type)
  path = send("#{type}_path")
  return unless path
  if File.exist?(path)
    pretty_path = path.sub("#{Lono.root}/",'')
    puts "Using param: #{pretty_path}".color(:yellow)
  end
end

#render_erb(path) ⇒ Object 



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# File 'lib/lono/param/generator.rb', line 140

def render_erb(path)
  return unless path
  if File.exist?(path)
    RenderMePretty.result(path, context: context)
  end
end

#source_exist? ⇒ Boolean

Checks both base and source path for existing of the param file. Example:

params/base/mystack.txt - base path
params/production/mystack.txt - source path

Returns:

  • (Boolean) 


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# File 'lib/lono/param/generator.rb', line 97

def source_exist?
  @base_path && File.exist?(@base_path) ||
  @env_path && File.exist?(@env_path)
end

#write_output(json) ⇒ Object 



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# File 'lib/lono/param/generator.rb', line 208

def write_output(json)
  dir = File.dirname(output_path)
  FileUtils.mkdir_p(dir)
  IO.write(output_path, json)
end