* Allowing users to provide a custom timeout as input for aborting download of a cache segment using an environment variable `SEGMENT_DOWNLOAD_TIMEOUT_MINS`. Default is 10 minutes.
Create a workflow `.yml` file in your repository's `.github/workflows` directory. An [example workflow](#example-cache-workflow) is available below. For more information, see the GitHub Help Documentation for [Creating a workflow file](https://help.github.com/en/articles/configuring-a-workflow#creating-a-workflow-file).
If you are using a `self-hosted` Windows runner, `GNU tar` and `zstd` are required for [Cross-OS caching](https://github.com/actions/cache/blob/main/tips-and-workarounds.md#cross-os-cache) to work. They are also recommended to be installed in general so the performance is on par with `hosted` Windows runners.
*`path` - A list of files, directories, and wildcard patterns to cache and restore. See [`@actions/glob`](https://github.com/actions/toolkit/tree/main/packages/glob) for supported patterns.
*`enableCrossOsArchive` - An optional boolean when enabled, allows Windows runners to save or restore caches that can be restored or saved respectively on other platforms. Default: `false`
*`fail-on-cache-miss` - Fail the workflow if cache entry is not found. Default: `false`
*`SEGMENT_DOWNLOAD_TIMEOUT_MINS` - Segment download timeout (in minutes, default `10`) to abort download of the segment if not completed in the defined number of minutes. [Read more](https://github.com/actions/cache/blob/main/tips-and-workarounds.md#cache-segment-restore-timeout)
> **Note** `cache-hit` will only be set to `true` when a cache hit occurs for the exact `key` match. For a partial key match via `restore-keys` or a cache miss, it will be set to `false`.
See [Matching a cache key](https://help.github.com/en/actions/configuring-and-managing-workflows/caching-dependencies-to-speed-up-workflows#matching-a-cache-key) for more info.
The `cache` action provides a `cache-hit` output which is set to `true` when the cache is restored using the primary `key` and `false` when the cache is restored using `restore-keys` or no cache is restored.
> You must use the `cache` or `restore` action in your workflow before you need to use the files that might be restored from the cache. If the provided `key` matches an existing cache, a new cache is not created and if the provided `key` doesn't match an existing cache, a new cache is automatically created provided the job completes successfully.
With the introduction of the `restore` and `save` actions, a lot of caching use cases can now be achieved. Please see the [caching strategies](./caching-strategies.md) document for understanding how you can use the actions strategically to achieve the desired goal.
For example, using the [`hashFiles`](https://docs.github.com/en/actions/learn-github-actions/expressions#hashfiles) function allows you to create a new cache when dependencies change.
See [Using contexts to create cache keys](https://help.github.com/en/actions/configuring-and-managing-workflows/caching-dependencies-to-speed-up-workflows#using-contexts-to-create-cache-keys)
Actions-cache-s3 don't have any limits in terms of size or age of the cache.
Eviction may be handled separately, for example using [S3 Lifecycle](https://docs.aws.amazon.com/AmazonS3/latest/userguide/object-lifecycle-mgmt.html).
Using the `cache-hit` output, subsequent steps (such as install or build) can be skipped when a cache hit occurs on the key. It is recommended to install missing/updated dependencies in case of a partial key match when the key is dependent on the `hash` of the package file.
Cache version is a hash [generated](https://github.com/actions/toolkit/blob/500d0b42fee2552ae9eeb5933091fe2fbf14e72d/packages/cache/src/internal/cacheHttpClient.ts#L73-L90) for a combination of compression tool used (Gzip, Zstd, etc. based on the runner OS) and the `path` of directories being cached. If two caches have different versions, they are identified as unique caches while matching. This, for example, means that a cache created on a `windows-latest` runner can't be restored on `ubuntu-latest` as cache `Version`s are different.
> Pro tip: The [list caches](https://docs.github.com/en/rest/actions/cache#list-github-actions-caches-for-a-repository) API can be used to get the version of a cache. This can be helpful to troubleshoot cache miss due to version.
The workflow will create 3 unique caches with same keys. Ubuntu and windows runners will use different compression technique and hence create two different caches. And `build-linux` will create two different caches as the `paths` are different.
There are a number of community practices/workarounds to fulfill specific requirements. You may choose to use them if they suit your use case. Note these are not necessarily the only solution or even a recommended solution.
Please note that Windows environment variables (like `%LocalAppData%`) will NOT be expanded by this action. Instead, prefer using `~` in your paths which will expand to the HOME directory. For example, instead of `%LocalAppData%`, use `~\AppData\Local`. For a list of supported default environment variables, see the [Learn GitHub Actions: Variables](https://docs.github.com/en/actions/learn-github-actions/variables#default-environment-variables) page.
We would love for you to contribute to `actions/cache`. Pull requests are welcome! Please see the [CONTRIBUTING.md](CONTRIBUTING.md) for more information.
