Trouble in caching dependency in CircleCI

Background

I am doing some tests in CircleCI but used our own docker image instead of CircleCI's one, so I'd like to install dockerize to do some monitor tasks.

When trying to cache the dependency in CircleCI in an irregular way, I got an error as the following.

Error computing cache key: template: cacheKey:1: unexpected unclosed action in command

The part of config file:

jobs:
  test:
    steps:
      - run:
          name: create dockerize version file
          command: echo "${DOCKERIZE_VERSION}" > /tmp/_dockerize_version_file
      - restore_cache:
          key: dockerize-bin-cache-{{ checksum "/tmp/_dockerize_version_file" }}
      - run:
          name: install dockerize utility
          command: |
            if ( ! type dockerize > /dev/null 2>&1 ) || [[ "$(dockerize --version)" != "$DOCKERIZE_VERSION" ]]; then
              wget https://github.com/jwilder/dockerize/releases/download/$DOCKERIZE_VERSION/dockerize-linux-amd64-$DOCKERIZE_VERSION.tar.gz
              tar -C /usr/local/bin -xzvf dockerize-linux-amd64-$DOCKERIZE_VERSION.tar.gz
              rm dockerize-linux-amd64-$DOCKERIZE_VERSION.tar.gz
            else
              echo "Binary exists. Dockerize's installation is skipped."
            fi
      - save_cache:
          key: dockerize-bin-cache-{{ checksum "/tmp/_dockerize_version_file" }}
          paths:
            - /usr/local/bin/dockerize
      - run:
          name: cleanup dockerize version file
          command: rm -rf /tmp/_dockerize_version_file

Solution

Couldn't find any solutions from the official document and forums and finally solved it by using the old style cache syntax.

jobs:
  test:
    steps:
      - run:
          name: create dockerize version file
          command: echo "${DOCKERIZE_VERSION}" > /tmp/_dockerize_version_file
      - type: cache-restore
        key: dockerize-bin-cache-{{ checksum "/tmp/_dockerize_version_file" }}
      - run:
          name: install dockerize utility
          command: |
            if ( ! type dockerize > /dev/null 2>&1 ) || [[ "$(dockerize --version)" != "$DOCKERIZE_VERSION" ]]; then
              wget https://github.com/jwilder/dockerize/releases/download/$DOCKERIZE_VERSION/dockerize-linux-amd64-$DOCKERIZE_VERSION.tar.gz
              tar -C /usr/local/bin -xzvf dockerize-linux-amd64-$DOCKERIZE_VERSION.tar.gz
              rm dockerize-linux-amd64-$DOCKERIZE_VERSION.tar.gz
            else
              echo "Binary exists. Dockerize's installation is skipped."
            fi
      - type: cache-save
        key: dockerize-bin-cache-{{ checksum "/tmp/_dockerize_version_file" }}
        paths:
          - /usr/local/bin/dockerize
      - run:
          name: cleanup dockerize version file
          command: rm -rf /tmp/_dockerize_version_file

You may want to ask why not use the DOCKERIZE_VERSION env var directly instead of saving to a tempfile. Actually I tried to set the env var in job scope, step scope, in shell but failed on all cases. There is a feature request. The official document tells us {{ .Environment.XXX }} can be used to retrieve exported or context based env var. I didn't try that.

Reference

Official document of restore_cache
Cannot use circle.yml environment variables in cache keys