How to handle GitHub Actions deleting its cache after 7 days - github-actions

Question

I have a GitHub Action that runs tests for my Python/Django project. It caches the virtual environment that Pipenv creates. Here's the workflow with nearly everything but the relevant steps commented out/removed:
jobs:
build:
runs-on: ubuntu-latest
services:
# postgres:
steps:
#- uses: actions/checkout#v2
#- name: Set up Python
#- name: Install pipenv and coveralls
- name: Cache pipenv virtualenv
uses: actions/cache#v2
id: pipenv-cache
with:
path: ~/.pipenv
key: ${{ runner.os }}-pipenv-v4-${{ hashFiles('**/Pipfile.lock') }}
restore-keys: |
${{ runner.os }}-pipenv-v4-
- name: Install dependencies
env:
WORKON_HOME: ~/.pipenv/virtualenvs
PIPENV_CACHE_DIR: ~/.pipenv/pipcache
if: steps.pipenv-cache.outputs.cache-hit != 'true'
run: pipenv install --dev
# Run tests etc.
This works fine usually, but because caches are removed after 7 days, if this is run less frequently than that, it can't find the cache and the Install Dependencies step fails with:
FileNotFoundError: [Errno 2] No such file or directory: '/home/runner/.pipenv/virtualenvs/my-project-CfczyyRI/bin/pip'
I then bump the cache key's version number (v4 above) and the action runs OK.
I thought the if: steps.pipenv-cache.outputs.cache-hit != 'true' would fix this but it doesn't. What am I missing?

Answer 1

First alternative: using a separate workflow, with a schedule trigger event, you can run workflows on a recurring schedule.
That way, you force a refresh of those dependencies in the workflow cache.
Second alternative: use github.rest.actions.getActionsCacheList from actions/github-script (as seen here) again in a separate workflow, just to read said cache, and check if it still disappear after 7 days.
Third alternative: check if reading the cache through the new Web UI is enough to force a refresh.
On that third point (Oct. 2022):
Manage caches in your Actions workflows from Web Interface
Caching dependencies and other commonly reused files enables developers to speed up their GitHub Actions workflows and make them more efficient.
We have now enabled Cache Management from the web interface to enable developers to get more transparency and control over their cache usage within their GitHub repositories.
Actions users who use actions/cache can now:
View a list of all cache entries for a repository.
Filter and sort the list of caches using specific metadata such as cache size, creation time, or last accessed time.
Delete a corrupt or a stale cache entry
Monitor aggregate cache usage for repositories and organizations.
In addition to the Cache Management UX that we have now enabled, you could also use our Cache APIs or install the GitHub CLI extension for Actions cache to manage your caches from your terminal.
Learn more about dependency caching to speed up your Actions workflows.