Class: Pupistry::Packer

Inherits:
Object
  • Object
show all
Defined in:
lib/pupistry/packer.rb

Overview

Pupistry::Packer

Instance Attribute Summary collapse

Instance Method Summary collapse

Constructor Details

#initialize ⇒ Packer

Returns a new instance of Packer.



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# File 'lib/pupistry/packer.rb', line 12

def initialize
  # We need to find where the templates are located - either it should be
  # in the current working directory, or if we are an installed gem, we
  # can try the gem's installed path.

  if Dir.exist?('resources/packer/')
    # Use local PWD version first if possible
    @template_dir = Dir.pwd
  else
    # Check for GEM installed location
    begin
      @template_dir = Gem::Specification.find_by_name('pupistry').gem_dir
    rescue Gem::LoadError
      $logger.error "Unable to find packer templates directory, doesn't appear we are running from project dir nor as a Gem"
      return false
    end
  end

  @template_dir = @template_dir.chomp('/') + '/resources/packer/'

  if Dir.exist?(@template_dir)
    $logger.debug "Using directory #{@template_dir} for packer templates"
  else
    $logger.error "Unable to find packer templates dir at #{@template_dir}, unable to proceed."
    return false
  end
end

Instance Attribute Details

#contents ⇒ Object

Returns the value of attribute contents.



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# File 'lib/pupistry/packer.rb', line 10

def contents
  @contents
end

#template_dir ⇒ Object

Returns the value of attribute template_dir.



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# File 'lib/pupistry/packer.rb', line 9

def template_dir
  @template_dir
end

Instance Method Details

#build(template) ⇒ Object 



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# File 'lib/pupistry/packer.rb', line 49

def build(template)
  # Build a template with the configured parameters already to go and save
  # into the object, so it can be outputted in the desired format.

  $logger.debug "Generating a packer template using #{template}"

  unless File.exist?("#{@template_dir}/#{template}.json.erb")
    $logger.error 'The requested template does not exist, unable to build'
    return 0
  end

  # Extract the OS bootstrap name from the template filename, we can then
  # generate the bootstrap commands to be inserted inline into the packer
  # configuration.

  matches = template.match(/^\S*_(\S*)$/)

  if matches[1]
    $logger.debug "Fetching bootstrap data for #{matches[1]}..."
  else
    $logger.error 'Unable to parse the packer filename properly'
    return 0
  end

  bootstrap = Pupistry::Bootstrap.new
  unless bootstrap.build matches[1]
    $logger.error 'An unexpected error occured when building the bootstrap data to go inside Packer'
  end

  # Pass the values we care about to the template
  template_values = {
    bootstrap_commands: bootstrap.output_array
  }

  # Generate template using ERB
  begin
    @contents = Erubis::Eruby.new(File.read("#{@template_dir}/#{template}.json.erb")).result(template_values)
  rescue StandardError => e
    $logger.error 'An unexpected error occured when trying to generate the packer template'
    raise e
  end
end

#list ⇒ Object 



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# File 'lib/pupistry/packer.rb', line 40

def list
  # Simply glob the templates directory and list their names.
  $logger.debug 'Finding all available templates'

  Dir.glob("#{@template_dir}/*.erb").each do |file|
    puts "- #{File.basename(file, '.json.erb')}"
  end
end

#output_file(filename) ⇒ Object 



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# File 'lib/pupistry/packer.rb', line 100

def output_file(filename)
  # Write the template to the specified file
  begin
    File.open(filename, 'w') do |f|
      f.puts @contents
    end
  rescue StandardError => e
    $logger.error "An unexpected erorr occured when attempting to write the template to #{filename}"
    raise e
  else
    $logger.info "Wrote template into file #{filename} successfully."
  end
end

#output_plain ⇒ Object 



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# File 'lib/pupistry/packer.rb', line 92

def output_plain
  # Do nothing clever, just output the template data.
  puts '-- Packer Start --'
  puts @contents
  puts '-- Packer End --'
  puts 'Tip: add --file output.json to write out the packer file directly and then run with `packer build output.json`'
end