Clear cache in GitHub Actions - caching

Question

I am working on an R package and using GitHub Action (GHA) as a Continuous Integration (CI) provider. I cache R packages (dependencies) by using actions/cache. And now I want to clear all cache. How can I do that?
A part of GHA Workflow I use:
on: push
name: R-CMD-check
jobs:
R-CMD-check:
runs-on: ${{ matrix.config.os }}
name: ${{ matrix.config.os }} (${{ matrix.config.r }})
strategy:
fail-fast: false
matrix:
config:
# - {os: windows-latest, r: 'devel'}
- {os: macOS-latest, r: 'release'}
env:
R_REMOTES_NO_ERRORS_FROM_WARNINGS: true
RSPM: ${{ matrix.config.rspm }}
GITHUB_PAT: ${{ secrets.GITHUB_TOKEN }}
steps:
- uses: actions/checkout#v2
- uses: r-lib/actions/setup-r#master
- name: Query dependencies
run: |
repos <- c("https://r-hyperspec.github.io/hySpc.pkgs/", getOption("repos"))
saveRDS("remotes::dev_package_deps(dependencies = TRUE)", ".github/depends.Rds", version = 2)
writeLines(sprintf("R-%i.%i", getRversion()$major, getRversion()$minor), ".github/R-version")
shell: Rscript {0}
- name: Cache R packages
if: runner.os != 'Windows'
uses: actions/cache#v1
with:
path: ${{ env.R_LIBS_USER }}
key: ${{ runner.os }}-${{ hashFiles('.github/R-version') }}-1-${{ hashFiles('.github/depends.Rds') }}
restore-keys: ${{ runner.os }}-${{ hashFiles('.github/R-version') }}-1-
- name: Install dependencies
run: remotes::install_deps(dependencies = TRUE)
shell: Rscript {0}
- name: Session info
run: |
options(width = 100)
pkgs <- installed.packages()[, "Package"]
sessioninfo::session_info(pkgs, include_base = TRUE)
shell: Rscript {0}

Answer 1

Update (October 20, 2022)
You can now manage caches via the UI:
https://github.com/<OWNER>/<REPO>/actions/caches
Update (June 27, 2022)
You can now manage caches via the GitHub Actions Cache API:
GET list of caches for a repository:
$ curl \
-H "Accept: application/vnd.github.v3+json" \
-H "Authorization: token <TOKEN>" \
https://api.github.com/repos/OWNER/REPO/actions/caches
DELETE cache for a repository using a cache ID:
$ curl \
-X DELETE \
-H "Accept: application/vnd.github.v3+json" \
-H "Authorization: token <TOKEN>" \
https://api.github.com/repos/OWNER/REPO/actions/caches/CACHE_ID
Alternatively, you can also use the GitHub CLI to interact with the API, using the gh-actions-cache extension.
Original Post (November 13, 2020)
As pointed out in the corresponding issue, two practical workarounds can be used to force the use of a new cache. This is not exactly the same as clearing the current cache (with regards to the cache usage limits), but it does the job.
In order to do so, you have to change the cache key (and any restore-keys). Because if the key(s) is/are different, this is considered a cache miss and you start with a new one.
You can change the cache key either by modifying the workflow file directly, e.g., by adding a version number:
key: ${{ runner.os }}-mycache-v1-${{ hashFiles(...) }}
If you now want to use a new cache, all you have to do is to commit a different version number:
key: ${{ runner.os }}-mycache-v2-${{ hashFiles(...) }}
If you don't want to modify the workflow file and prefer using the UI, you can abuse secrets:
key: ${{ runner.os }}-mycache-${{ secrets.CACHE_VERSION }}-${{ hashFiles(...) }}
Whenever the secret changes, a new cache will be used.
⚠️ WARNING: Secrets used for cache keys are "revealed" in the UI.

Answer 2

You cannot force a clear cache currently and it seems there is an open feature request for it at the moment https://github.com/actions/cache/issues/2. If I were you, I would post the request there as well so that they know that more people want the feature implemented.
A few things to note about the action:
There are not parameters in the action and not even in the toolkit package that this action is build on top of.
Getting deep into the toolkit code they use a cache api url to do all the good stuff. This means we don't even know if that api supports it with the assumption that we try to test it out and see what else it provides by hitting it directly. Here is the line for the api call for which the base url is taken from env ACTIONS_CACHE_URL
https://github.com/actions/toolkit/blob/c2bc747506bf562195a02bd4fdb1ff2a95d8b7ed/packages/cache/src/internal/cacheHttpClient.ts#L44
npm package as reference https://www.npmjs.com/package/#actions/cache
If we take a step back for a moment and go back to the github docs now that we have looked deep into the action/cache code and how it works,
Per the github docs https://docs.github.com/en/actions/configuring-and-managing-workflows/caching-dependencies-to-speed-up-workflows
There are two things to note,
Once you create a cache, you cannot change the contents of an existing
cache but you can create a new cache with a new key.
GitHub will remove any cache entries that have not been accessed in over 7 days.

Answer 3

This can be done from GH Actions as well.
name: Clear cache
on:
workflow_dispatch:
permissions:
actions: write
jobs:
clear-cache:
runs-on: ubuntu-latest
steps:
- name: Clear cache
uses: actions/github-script#v6
with:
script: |
console.log("About to clear")
const caches = await github.rest.actions.getActionsCacheList({
owner: context.repo.owner,
repo: context.repo.repo,
})
for (const cache of caches.data.actions_caches) {
console.log(cache)
github.rest.actions.deleteActionsCacheById({
owner: context.repo.owner,
repo: context.repo.repo,
cache_id: cache.id,
})
}
console.log("Clear completed")
Make sure it's merged to HEAD branch and trigger it manually from Actions.

Answer 4

Based #beatngu13 answer I've created Makefile target that remove all cache from Github Actions:
GH_REPO ?= ALLATRA-IT/ephyr # replace with your `org/repo`
# Clear Github Acions usage cache.
#
# Need to install github cli first [https://cli.github.com/] and authorize
#
# Usage:
# make gh.clear
gh.clear:
gh api -H "Accept: application/vnd.github+json" \
/repos/$(GH_REPO)/actions/caches \
| for ID in `jq '.actions_caches[].id'`; \
do echo "Deleting $$ID"; \
gh api --method DELETE /repos/$(GH_REPO)/actions/caches/$$ID | echo; done
Need to install Github CLI and jq tool tools first. After install Github CLI you need to authorize with:
gh auth login

Answer 5

#GegznaV you can use something like tmate, and manually clear cache by sshing into a runner.

Answer 6

For anyone looking for a simple commandline solution, the following shell command will also do it. It requires the Github CLI + JQ:
gh api -H 'Accept: application/vnd.github+json' /repos/realm/realm-kotlin/actions/caches --paginate | jq -r '.actions_caches | .[].key' | sed -e 's/|/%7c/g' -e 's/\[/%5b/g' -e 's/\]/%5d/g' | xargs -I {} sh -c 'gh api --method DELETE -H "Accept: application/vnd.github+json" /repos/<OWNER>/<REPO>/actions/caches?key={} --silent'
In this case, I'm using sed to URL encode special characters in the key. I just needed to handle |, [ and ]. Others can be added as needed. See e.g. https://gist.github.com/jaytaylor/5a90c49e0976aadfe0726a847ce58736#file-url_encode-sh-L11

Answer 7

One more easy and straightforward way to remove Actions' cache - Purge cache GH Action.
This action allows the cache of GitHub Actions to be automatically purged based on the last usage and configured TTL (default - 7 days).
Example:
name: Clear Cache
on:
schedule:
- cron: '0 0 * * *' # Runs once a day (https://crontab.guru/once-a-day)
jobs:
clear:
name: Clear cache
runs-on: ubuntu-latest
steps:
- uses: MyAlbum/purge-cache#v1
with:
max-age: 604800 # Cache max 7 days since last use (this is the default)
The workflow above will run once a day and remove all the cache that was last used more than 7 days ago.

Answer 8

Here's another automated solution similar to #beatngu13's cache key invalidation method. This one uses a generated timestamp file that gets committed and then used in a hashFiles(...) prefix to the cache key.
Included is a set of GNU Makefile targets to make using this method very easy: make clear-github-cache
Note: Make sure each Makefile "recipe" section is indented with 1 tab character! StackOverflow converts tabs to spaces in the code block.
.github/clear_github_actions_cache:
date +%s > .github/clear_github_actions_cache
.PHONY: clean-github-cache-file clear-github-cache
clear-github-cache: clean-github-cache-file .github/clear_github_actions_cache ## Force GitHub Actions Cache key to change for fresh CI run
git add .github/clear_github_actions_cache
git commit -m "Clear GitHub Actions Cache # $$(cat .github/clear_github_actions_cache)"
clean-github-cache-file: ## Remove GitHub Actions Cache timestamp invalidator file.
[ -f '.github/clear_github_actions_cache' ] && rm -f '.github/clear_github_actions_cache' || true
Then, inside the GitHub Actions workflow YAML, add a cache key prefix that uses the hash of this file:
- name: Cache R packages
if: runner.os != 'Windows'
uses: actions/cache#v2
with:
path: ${{ env.R_LIBS_USER }}
key: ${{ runner.os }}-${{ runner.arch }}-${{ hashFiles('.github/clear_github_actions_cache') }}-${{ hashFiles('.github/R-version') }}-${{ hashFiles('.github/depends.Rds') }}
restore-keys: |
${{ runner.os }}-${{ runner.arch }}-${{ hashFiles('.github/clear_github_actions_cache') }}-${{ hashFiles('.github/R-version') }}-${{ hashFiles('.github/depends.Rds') }}
${{ runner.os }}-${{ runner.arch }}-${{ hashFiles('.github/clear_github_actions_cache') }}-${{ hashFiles('.github/R-version') }}-
${{ runner.os }}-${{ runner.arch }}-${{ hashFiles('.github/clear_github_actions_cache') }}-
Now just run:
make clear-github-cache
This generates and commits a file, .github/clear_github_actions_cache, with Unix timestamp as contents. The hashFiles(...) cache key prefix uses this and will generate a unique hash of this file as a prefix to the rest of the cache / restore-key.
Next time you use git push, the cache key will be invalidated... effectively running GitHub Actions with an empty cache.