mirror of
https://github.com/actions/cache.git
synced 2024-12-27 01:40:36 +01:00
83 lines
5.1 KiB
Markdown
83 lines
5.1 KiB
Markdown
## Cache segment restore timeout
|
|
A cache gets downloaded in multiple segments of fixed sizes (`1GB` for a `32-bit` runner and `2GB` for a `64-bit` runner). Sometimes, a segment download gets stuck which causes the workflow job to be stuck forever and fail. Version `v3.0.8` of `actions/cache` introduces a segment download timeout. The segment download timeout will allow the segment download to get aborted and hence allow the job to proceed with a cache miss.
|
|
|
|
Default value of this timeout is 60 minutes and can be customized by specifying an [environment variable](https://docs.github.com/en/actions/learn-github-actions/environment-variables) named `SEGMENT_DOWNLOAD_TIMEOUT_MINS` with timeout value in minutes.
|
|
|
|
## Update a cache
|
|
A cache today is immutable and cannot be updated. But some use cases require the cache to be saved even though there was a "hit" during restore. To do so, use a `key` which is unique for every run and use `restore-keys` to restore the nearest cache. For example:
|
|
```yaml
|
|
- name: update cache on every commit
|
|
uses: actions/cache@v3
|
|
with:
|
|
path: prime-numbers
|
|
key: primes-${{ runner.os }}-${{ github.run_id }} # Can use time based key as well
|
|
restore-keys: |
|
|
primes-${{ runner.os }}
|
|
```
|
|
Please note that this will create a new cache on every run and hence will consume the cache [quota](./README.md#cache-limits).
|
|
|
|
## Use cache across feature branches
|
|
Reusing cache across feature branches is not allowed today to provide cache [isolation](https://docs.github.com/en/actions/using-workflows/caching-dependencies-to-speed-up-workflows#restrictions-for-accessing-a-cache). However if both feature branches are from the default branch, a good way to achieve this is to ensure that the default branch has a cache. This cache will then be consumable by both feature branches.
|
|
|
|
## Improving cache restore performance on Windows/Using cross-os caching
|
|
Currently, cache restore is slow on Windows due to tar being inherently slow and the compression algorithm `gzip` in use. `zstd` is the default algorithm in use on linux and macos. It was disabled on Windows due to issues with bsd tar(libarchive), the tar implementation in use on Windows.
|
|
|
|
To improve cache restore performance, we can re-enable `zstd` as the compression algorithm using the following workaround. Add the following step to your workflow before the cache step:
|
|
|
|
```yaml
|
|
- if: ${{ runner.os == 'Windows' }}
|
|
name: Use GNU tar
|
|
shell: cmd
|
|
run: |
|
|
echo "Adding GNU tar to PATH"
|
|
echo C:\Program Files\Git\usr\bin>>"%GITHUB_PATH%"
|
|
```
|
|
|
|
The `cache` action will use GNU tar instead of bsd tar on Windows. This should work on all Github Hosted runners as it is. For self-hosted runners, please ensure you have GNU tar and `zstd` installed.
|
|
|
|
The above workaround is also needed if you wish to use cross-os caching since difference of compression algorithms will result in different cache versions for the same cache key. So the above workaround will ensure `zstd` is used for caching on all platforms thus resulting in the same cache version for the same cache key.
|
|
|
|
## Force deletion of caches overriding default cache eviction policy
|
|
Caches have [branch scope restriction](https://docs.github.com/en/actions/using-workflows/caching-dependencies-to-speed-up-workflows#restrictions-for-accessing-a-cache) in place. This means that if caches for a specific branch are using a lot of storage quota, it may result into more frequently used caches from `default` branch getting thrashed. For example, if there are many pull requests happening on a repo and are creating caches, these cannot be used in default branch scope but will still occupy a lot of space till they get cleaned up by [eviction policy](https://docs.github.com/en/actions/using-workflows/caching-dependencies-to-speed-up-workflows#usage-limits-and-eviction-policy). But sometime we want to clean them up on a faster cadence so as to ensure default branch is not thrashing. In order to achieve this, [gh-actions-cache cli](https://github.com/actions/gh-actions-cache/) can be used to delete caches for specific branches.
|
|
|
|
This workflow uses `gh-actions-cache` to delete all the caches created by a branch.
|
|
<details>
|
|
<summary>Example</summary>
|
|
|
|
```yaml
|
|
name: cleanup caches by a branch
|
|
on:
|
|
pull_request:
|
|
types:
|
|
- closed
|
|
workflow_dispatch:
|
|
|
|
jobs:
|
|
cleanup:
|
|
runs-on: ubuntu-latest
|
|
steps:
|
|
- name: Check out code
|
|
uses: actions/checkout@v3
|
|
|
|
- name: Cleanup
|
|
run: |
|
|
gh extension install actions/gh-actions-cache
|
|
|
|
REPO=${{ github.repository }}
|
|
BRANCH=${{ github.ref }}
|
|
|
|
echo "Fetching list of cache key"
|
|
cacheKeysForPR=$(gh actions-cache list -R $REPO -B $BRANCH | cut -f 1 )
|
|
|
|
## Setting this to not fail the workflow while deleting cache keys.
|
|
set +e
|
|
echo "Deleting caches..."
|
|
for cacheKey in $cacheKeysForPR
|
|
do
|
|
gh actions-cache delete $cacheKey -R $REPO -B $BRANCH --confirm
|
|
done
|
|
echo "Done"
|
|
env:
|
|
GH_TOKEN: ${{ secrets.GITHUB_TOKEN }}
|
|
```
|
|
</details>
|