Registry Cache Parameters and Usage

2nd chunk of `content/manuals/build/cache/backends/registry.md`

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  --cache-from type=registry,ref=<registry>/<cache-image> .
```

The following table describes the available CSV parameters that you can pass to
`--cache-to` and `--cache-from`.

| Name                | Option                  | Type                    | Default | Description                                                                                                                     |
|---------------------|-------------------------|-------------------------|---------|---------------------------------------------------------------------------------------------------------------------------------|
| `ref`               | `cache-to`,`cache-from` | String                  |         | Full name of the cache image to import.                                                                                         |
| `mode`              | `cache-to`              | `min`,`max`             | `min`   | Cache layers to export, see [cache mode][1].                                                                                    |
| `oci-mediatypes`    | `cache-to`              | `true`,`false`          | `true`  | Use OCI media types in exported manifests, see [OCI media types][2].                                                            |
| `image-manifest`    | `cache-to`              | `true`,`false`          | `true`  | When using OCI media types, generate an image manifest instead of an image index for the cache image, see [OCI media types][2]. |
| `compression`       | `cache-to`              | `gzip`,`estargz`,`zstd` | `gzip`  | Compression type, see [cache compression][3].                                                                                   |
| `compression-level` | `cache-to`              | `0..22`                 |         | Compression level, see [cache compression][3].                                                                                  |
| `force-compression` | `cache-to`              | `true`,`false`          | `false` | Forcibly apply compression, see [cache compression][3].                                                                         |
| `ignore-error`      | `cache-to`              | Boolean                 | `false` | Ignore errors caused by failed cache exports.                                                                                   |


You can choose any valid value for `ref`, as long as it's not the same as the
target location that you push your image to. You might choose different tags
(e.g. `foo/bar:latest` and `foo/bar:build-cache`), separate image names (e.g.
`foo/bar` and `foo/bar-cache`), or even different repositories (e.g.
`docker.io/foo/bar` and `ghcr.io/foo/bar`). It's up to you to decide the
strategy that you want to use for separating your image from your cache images.

If the `--cache-from` target doesn't exist, then the cache import step will
fail, but the build continues.

## Further reading

For an introduction to caching see [Docker build cache](../_index.md).

For more information on the `registry` cache backend, see the
[BuildKit README](https://github.com/moby/buildkit#registry-push-image-and-cache-separately).

Title: Registry Cache Parameters and Usage

Summary

This section details the configuration parameters for the `registry` cache in Buildx, including `ref`, `mode`, `oci-mediatypes`, `image-manifest`, `compression`, `compression-level`, `force-compression`, and `ignore-error`. It explains how to specify the cache image and its settings, and how to handle scenarios where the `--cache-from` target does not exist. It also points to resources for further reading about caching and the `registry` cache backend.