configuration.rb

require "active_support/ordered_options"
require "active_support/core_ext/string/inquiry"
require "active_support/core_ext/module/delegation"
require "pathname"
require "erb"
require "net/ssh/proxy/jump"

class Mrsk::Configuration
  delegate :service, :image, :servers, :env, :labels, :registry, :builder, :stop_wait_time, to: :raw_config, allow_nil: true
  delegate :argumentize, :argumentize_env_with_secrets, :optionize, to: Mrsk::Utils

  attr_accessor :destination
  attr_accessor :raw_config

  class << self
    def create_from(config_file:, destination: nil, version: nil)
      raw_config = load_config_files(config_file, *destination_config_file(config_file, destination))

      new raw_config, destination: destination, version: version
    end

    private
      def load_config_files(*files)
        files.inject({}) { |config, file| config.deep_merge! load_config_file(file) }
      end

      def load_config_file(file)
        if file.exist?
          YAML.load(ERB.new(IO.read(file)).result).symbolize_keys
        else
          raise "Configuration file not found in #{file}"
        end
      end

      def destination_config_file(base_config_file, destination)
        base_config_file.sub_ext(".#{destination}.yml") if destination
      end
  end

  def initialize(raw_config, destination: nil, version: nil, validate: true)
    @raw_config = ActiveSupport::InheritableOptions.new(raw_config)
    @destination = destination
    @declared_version = version
    valid? if validate
  end


  def version=(version)
    @declared_version = version
  end

  def version
    @declared_version.presence || ENV["VERSION"] || current_commit_hash
  end

  def abbreviated_version
    Mrsk::Utils.abbreviate_version(version)
  end


  def roles
    @roles ||= role_names.collect { |role_name| Role.new(role_name, config: self) }
  end

  def role(name)
    roles.detect { |r| r.name == name.to_s }
  end

  def accessories
    @accessories ||= raw_config.accessories&.keys&.collect { |name| Mrsk::Configuration::Accessory.new(name, config: self) } || []
  end

  def accessory(name)
    accessories.detect { |a| a.name == name.to_s }
  end


  def all_hosts
    roles.flat_map(&:hosts).uniq
  end

  def primary_web_host
    role(:web).primary_host
  end

  def traefik_hosts
    roles.select(&:running_traefik?).flat_map(&:hosts).uniq
  end


  def repository
    [ raw_config.registry["server"], image ].compact.join("/")
  end

  def absolute_image
    "#{repository}:#{version}"
  end

  def latest_image
    "#{repository}:latest"
  end

  def service_with_version
    "#{service}-#{version}"
  end


  def env_args
    if raw_config.env.present?
      argumentize_env_with_secrets(raw_config.env)
    else
      []
    end
  end

  def volume_args
    if raw_config.volumes.present?
      argumentize "--volume", raw_config.volumes
    else
      []
    end
  end

  def logging_args
    if raw_config.logging.present?
      optionize({ "log-driver" => raw_config.logging["driver"] }.compact) +
        argumentize("--log-opt", raw_config.logging["options"])
    else
      argumentize("--log-opt", { "max-size" => "10m" })
    end
  end


  def ssh_user
    if raw_config.ssh.present?
      raw_config.ssh["user"] || "root"
    else
      "root"
    end
  end

  def ssh_proxy
    if raw_config.ssh.present? && raw_config.ssh["proxy"]
      Net::SSH::Proxy::Jump.new \
        raw_config.ssh["proxy"].include?("@") ? raw_config.ssh["proxy"] : "root@#{raw_config.ssh["proxy"]}"
    elsif raw_config.ssh.present? && raw_config.ssh["proxy_command"]
      Net::SSH::Proxy::Command.new(raw_config.ssh["proxy_command"])
    end
  end

  def ssh_options
    { user: ssh_user, proxy: ssh_proxy, auth_methods: [ "publickey" ] }.compact
  end


  def audit_broadcast_cmd
    raw_config.audit_broadcast_cmd
  end

  def healthcheck
    { "path" => "/up", "port" => 3000, "max_attempts" => 7 }.merge(raw_config.healthcheck || {})
  end

  def readiness_delay
    raw_config.readiness_delay || 7
  end

  def valid?
    ensure_required_keys_present && ensure_env_available
  end


  def to_h
    {
      roles: role_names,
      hosts: all_hosts,
      primary_host: primary_web_host,
      version: version,
      repository: repository,
      absolute_image: absolute_image,
      service_with_version: service_with_version,
      env_args: env_args,
      volume_args: volume_args,
      ssh_options: ssh_options,
      builder: raw_config.builder,
      accessories: raw_config.accessories,
      logging: logging_args,
      healthcheck: healthcheck
    }.compact
  end

  def traefik
    raw_config.traefik || {}
  end

  private
    # Will raise ArgumentError if any required config keys are missing
    def ensure_required_keys_present
      %i[ service image registry servers ].each do |key|
        raise ArgumentError, "Missing required configuration for #{key}" unless raw_config[key].present?
      end

      if raw_config.registry["username"].blank?
        raise ArgumentError, "You must specify a username for the registry in config/deploy.yml"
      end

      if raw_config.registry["password"].blank?
        raise ArgumentError, "You must specify a password for the registry in config/deploy.yml (or set the ENV variable if that's used)"
      end

      roles.each do |role|
        if role.hosts.empty?
          raise ArgumentError, "No servers specified for the #{role.name} role"
        end
      end

      true
    end

    # Will raise KeyError if any secret ENVs are missing
    def ensure_env_available
      env_args
      roles.each(&:env_args)

      true
    end

    def role_names
      raw_config.servers.is_a?(Array) ? [ "web" ] : raw_config.servers.keys.sort
    end

    def current_commit_hash
      @current_commit_hash ||=
        if system("git rev-parse")
          `git rev-parse HEAD`.strip
        else
          raise "Can't use commit hash as version, no git repository found in #{Dir.pwd}"
        end
    end
end