Class: TerraformDSL

Inherits:
Object
  • Object
show all
Defined in:
lib/scout/terraform_dsl.rb,
lib/scout/terraform_dsl/util.rb,
lib/scout/terraform_dsl/deployment.rb

Overview

rubocop: disable Style/Documentation

Defined Under Namespace

Classes: Deployment, Module

Constant Summary collapse

MODULES_DIR = 
Scout.share.terraform
ANSIBLE_DIR = 
Scout.share.ansible
WORK_DIR = 
Scout.var.terraform

Instance Attribute Summary collapse

Class Method Summary collapse

Instance Method Summary collapse

Constructor Details

#initialize(modules = MODULES_DIR) ⇒ TerraformDSL

Create a new terraform deployment configuration

Parameters:

  • modules (String) (defaults to: MODULES_DIR) —

    directory containing module templates



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# File 'lib/scout/terraform_dsl.rb', line 93

def initialize(modules = MODULES_DIR)
  @modules = modules
  @elements = []
  @custom_files = []
  @variables = {}
  @element_files = []
end

Instance Attribute Details

#elements ⇒ Object

Returns the value of attribute elements.



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# File 'lib/scout/terraform_dsl.rb', line 10

def elements
  @elements
end

#modules ⇒ Object

Returns the value of attribute modules.



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# File 'lib/scout/terraform_dsl.rb', line 10

def modules
  @modules
end

#name ⇒ Object

Returns the value of attribute name.



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# File 'lib/scout/terraform_dsl.rb', line 10

def name
  @name
end

#processed_custom_files ⇒ Object

Returns the value of attribute processed_custom_files.



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# File 'lib/scout/terraform_dsl.rb', line 10

def processed_custom_files
  @processed_custom_files
end

#processed_elements ⇒ Object

Returns the value of attribute processed_elements.



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# File 'lib/scout/terraform_dsl.rb', line 10

def processed_elements
  @processed_elements
end

Class Method Details

.log(msg, prefix = nil) ⇒ Object

Log a message, optionally including a prefix between brakets

Parameters:

  • msg (String) —

    Message to log

  • prefix (nil, String) (defaults to: nil) —

    Optional prefix to prepend



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# File 'lib/scout/terraform_dsl/util.rb', line 14

def self.log(msg, prefix = nil)
  if prefix
    STDOUT.puts("[#{prefix}] " + msg)
  else
    STDOUT.puts(msg)
  end
end

.module_outputs(module_dir) ⇒ Hash

Gather information about the output variables of a terraform module

Parameters:

  • module_dir (String) —

    path to the directory with the module template files

Returns:

  • (Hash) —

    for each variable name holds a hash with the description



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# File 'lib/scout/terraform_dsl/util.rb', line 73

def self.module_outputs(module_dir)
  outputs = {}

  module_dir = module_dir.find if Path === module_dir
  file = module_dir['output.tf']
  return outputs unless Open.exist?(file)

  name, description, value = nil
  Open.read(file).split("\n").each do |line|
    if (m = line.match(/^\s*output\s+"([^"]*)"/))
      if name
        outputs[name] = { :description => description }
        name, description, value = nil
      end
      name = m[1].strip
    elsif (m = line.match(/description\s*=\s*"(.*)"/))
      description = m[1].strip
    end
  end

  if name
    outputs[name] = { :description => description }
  end

  outputs
end

.module_variables(module_dir) ⇒ Hash

Gather information about the input variables of a terraform module

Parameters:

  • module_dir (String) —

    path to the directory with the module template files

Returns:

  • (Hash) —

    for each variable name holds a hash with description, type and default values



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# File 'lib/scout/terraform_dsl/util.rb', line 34

def self.module_variables(module_dir)
  variables = {}

  file = module_dir['variables.tf']
  return variables unless Open.exist?(file)

  name, description, type, default = nil
  Open.read(file).split("\n").each do |line|
    if (m = line.match(/^\s*variable\s+"([^"]*)"/))
      if name
        variables[name] =
          { :description => description, :type => type, :default => default }
        name, description, type, default = nil
      end
      name = m[1].strip
    elsif (m = line.match(/description\s*=\s*"(.*)"/))
      description = m[1].strip
    elsif (m = line.match(/type\s*=\s*(.*)/))
      type = m[1].strip
    elsif (m = line.match(/default\s*=\s*(.*)/))
      default = begin
        JSON.parse(m[1].strip)
      rescue StandardError
        m[1].strip
      end
    end
  end

  if name
    variables[name] = { :description => description, :type => type, :default => default }
  end

  variables
end

.obj2digest(obj) ⇒ Object

Returns a md5 digest of an object based on its JSON representation

Parameters:

  • obj (Object) —

    object to digest



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# File 'lib/scout/terraform_dsl/util.rb', line 25

def self.obj2digest(obj)
  Digest::MD5.hexdigest(obj.to_json)
end

Instance Method Details

#add(provider = nil, module_name = nil, variables = {}) ⇒ Module

Add a new module instance

Parameters:

  • provider (String) (defaults to: nil) —

    first level of template organization subdirectory

  • module_name (String) (defaults to: nil) —

    subdirectory containing the module to use

  • variables (Hash) (defaults to: {}) —

    values for variables in the module template, and :name to name the module instance, and :outputs to define the module variables that will become deployment outputs

Returns:

  • (Module) —

    A module object used as a reference in Terraform templates



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# File 'lib/scout/terraform_dsl.rb', line 109

def add(provider = nil, module_name = nil, variables = {})
  variables[:name] ||= variables["name"] ||= [provider, module_name].join('_')
  module_directory = @modules[provider][module_name]
  @elements << [provider, module_name, module_directory, variables]
  @variables.merge!(variables)
  Module.new(variables[:name], module_name, self)
end

#config(dir = nil) ⇒ Object

Populate a directory all the necessary templates: modules, outputs, and custom

Parameters:

  • dir (String) (defaults to: nil) —

    directory from which to manage the deployment. If none provided a unique one will be generated based on a md5 digest of the elements defined



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# File 'lib/scout/terraform_dsl.rb', line 302

def config(dir = nil)
  dir = WORK_DIR[TerraformDSL.obj2digest(@elements)] if dir.nil?
  Open.mkdir dir
  main(dir)
  outputs(dir)
  custom_files(dir)
  @processed_elements ||= []
  @processed_elements.concat(@elements)
  @processed_custom_files ||= []
  @processed_custom_files.concat(@custom_files)
  @elements = []
  @custom_files = []
  dir
end

#custom(file, text) ⇒ Object

Add a terraform file with custom content. Used only to support defining non Hashicorp provider configuration

Parameters:

  • file (String) —

    name of the file

  • text (String) —

    content of the file



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# File 'lib/scout/terraform_dsl.rb', line 178

def custom(file, text)
  @custom_files << [file, text]
  nil
end

#custom_files(dir) ⇒ Object

Populate a directory with the terraform templates corresponding to the custom defined elements

Parameters:

  • dir (String) —

    directory from which to manage the deployment



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# File 'lib/scout/terraform_dsl.rb', line 249

def custom_files(dir)
  @custom_files.each do |element_file, text|
    Open.write(dir[element_file + '.tf'], text)
  end
end

#main(dir) ⇒ Object

Populate a directory with the terraform templates corresponding to the defined elements

Parameters:

  • dir (String) —

    directory from which to manage the deployment



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# File 'lib/scout/terraform_dsl.rb', line 142

def main(dir)
  @elements.each do |info|
    _provider, _module_name, template, variables = info

    template = template.find
    # Add an additional / to mark the base_path of the module directory and
    # allow modules to reference other modules relatively
    template = template.split('/').tap {|l| l[-2] = '/'+l[-2] } * '/'

    name = variables[:name]

    text =<<~EOF
        module "#{name}" {
          source = "#{template}"
        #{variable_block(variables)}
        }
    EOF

    element_file = [_module_name, name.to_s.sub(/_#{_module_name}$/,'')] * "."

    # rubocop: disable Layout/LineLength
    raise Deployment::TerraformException,
      "Warning: element file '#{element_file}' already exists, consider renaming it by using the parameter ':name'" if @element_files.include?(element_file)
    # rubocop: enable Layout/LineLength

    @element_files << element_file

    Open.write(dir[element_file + '.tf'], text)
  end
end

#outputs(dir) ⇒ Object

Populate a directory with the terraform templates corresponding to the defined element outputs variables

Parameters:

  • dir (String) —

    directory from which to manage the deployment



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# File 'lib/scout/terraform_dsl.rb', line 259

def outputs(dir)
  @elements.each do |info|
    _provider, module_name, template, variables = info
    outputs = variables[:outputs]
    module_outputs = TerraformDSL.module_outputs(template)
    outputs = module_outputs.keys if outputs.to_s == 'all'
    next unless outputs && outputs.any?

    name = variables[:name]

    outputs = outputs.collect do |o|
      (o.is_a?(String) || o.is_a?(Symbol)) && o.to_s == 'all' ? module_outputs.keys : o
    end.flatten.uniq if outputs.is_a?(Array)

    text = ''
    outputs.each do |output, output_rename = nil|
      output, output_rename = output.collect.first if output.is_a?(Hash)

      output_rename = output if output_rename.nil?

      description = module_outputs[output.to_s][:description]
      description ||= "Value of #{output} from module #{name} (type #{module_name})"

      text +=<<~EOF
          output "#{name}_#{output_rename}"{
            description = "#{description}"
            value = module.#{name}.#{output}
          }
      EOF
    end

    element_file = [module_name, name.to_s] * "."

    Open.write(dir[element_file + '.outputs.tf'], text)
  end
end

#provider(name, variables = {}) ⇒ nil, Module

Add a provider template file without using modules. Defining providers in modules is problematic when providers are not managed by Hashicorp. Hopefully we can find a fix for this soon.

Parameters:

  • name (String) —

    name of the provider

  • variables (Hash) (defaults to: {}) —

    variables for the provider: :source & :version

Returns:

  • (nil, Module) —

    If a Module is found at <modules_dir>/<name>/provider it returns it



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# File 'lib/scout/terraform_dsl.rb', line 193

def provider(name, variables = {})
  variables = variables.dup

  if Open.exist?(@modules[name].provider)
    provider = add name, :provider
  else
    provider = nil
  end

  source = variables.delete :source
  version = variables.delete :version

  text = ''

  if source
    if version
      text +=<<~EOF
          terraform {
            required_providers {
              #{name} = {
              source = "#{source}"
              version = "#{version}"
              }
            }
          }
      EOF
    else
      text +=<<~EOF
          terraform {
            required_providers {
              #{name} = {
              source = "#{source}"
              }
            }
          }
      EOF
    end
  end

  text +=<<~EOF
      provider "#{name}" {
      #{variable_block(variables)}
      }
  EOF

  element_file = ['provider_config', name.to_s].join('.')

  custom(element_file, text)

  provider
end

#variable_block(variables) ⇒ String

Terraform text that describes variables passed to a given module instance

Parameters:

  • variables (Hash) —

    module variables and their values, :name and :outputs are ignored as they are not module variables themselves

Returns:

  • (String) —

    text to include inside the terraform module definition containing the variable assignments



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# File 'lib/scout/terraform_dsl.rb', line 124

def variable_block(variables)
  variables.each_with_object([]) do |p, acc|
    name, value = p
    next acc if name.to_s == 'name'
    next acc if name.to_s == 'outputs'

    if value.is_a?(String) && (m = value.match(/^module\.(.*)\.(.*)/))
      value = Module::Output.new m[1], m[2]
    end

    acc << "  #{name} = #{value.to_json}"
  end * "\n"
end