CircleCIで環境変数(Environment Valuables, Context)が効かない

CircleCIで環境変数が効かない、環境変数が反映されない、という地味な現象にハマりましたが、原因はconfig.yaml内でsudo利用時に環境変数引き継ぎオプション-Eを指定していなかったという残念なものでした。
検索しても引っかからなかったので自分のためにメモ。

修正前

sudo yarn deploy       

修正後

sudo -E yarn deploy       

config.yaml全体

version: 2.1

references:
  ignore_master: &ignore_master
    filters:
      branches:
        ignore:
          - master

orbs:
  aws-cli: circleci/aws-cli@0.1.13

executors:
  default:
    working_directory: ~/repo
    docker:
      - image: circleci/node:10.15.3-browsers

commands:
  prepare-aws-cli:
    description: 'AWS CLIを準備'
    steps:
      - aws-cli/install
      - aws-cli/configure

  prepare-resources:
    description: 'リソースを準備'
    steps:
      - checkout

      - run:
          name: Install Yarn
          command: sudo npm install -g yarn@1.6.0

      - restore_cache:
          keys:
            - v2-dependencies-{{ checksum "package.json" }}-{{ checksum "serverless.yml" }}-{{ checksum "yarn.lock" }}
            - v2-dependencies-

      - run:
          name: Install dependencies
          command: |
            # yarn.lockの内容をすべてインストール
            yarn install --frozen-lockfile

      - save_cache:
          paths:
            - node_modules
          key: v2-dependencies-{{ checksum "package.json" }}-{{ checksum "serverless.yml" }}-{{ checksum "yarn.lock" }}

jobs:
  lint-and-test:
    executor:
      name: default

    steps:
      - prepare-resources

      - run: yarn lint

      - run:
          name: Format checking
          command: |
            yarn format;
            git diff --exit-code --quiet;
            if [ $? = 1 ]; then
              echo 'Unformat file(s) found.';
              exit 1
            fi

      - run: yarn test:coverage

      - store_artifacts:
          path: ~/repo/coverage/lcov-report/

  build:
    executor:
      name: default

    steps:
      - prepare-resources

      - prepare-aws-cli

      - run:
          name: Build Nuxt resources
          command: |
            if [ $ALIS_APP_ID ]; then
              sudo -E yarn build
            fi

      - persist_to_workspace:
          root: .
          paths:
            - .nuxt/*

  deploy:
    executor:
      name: default

    steps:
      - prepare-resources

      - prepare-aws-cli

      - attach_workspace:
          at: .

      - deploy:
          name: Deployment
          command: |
            if [ $ALIS_APP_ID ]; then
              sudo npm install -g serverless
              sudo -E yarn deploy
            fi

workflows:
  main:
    jobs:
      - lint-and-test
      - build:
          <<: *ignore_master
      - deploy:
          # ステージング環境、本番環境へのデプロイはCodeBuildに委ねる
          <<: *ignore_master
          requires:
            - lint-and-test
            - build