Add Alpine package registry (#23714)

This PR adds an Alpine package registry. You can follow [this
tutorial](https://wiki.alpinelinux.org/wiki/Creating_an_Alpine_package)
to build a *.apk package for testing.

This functionality is similar to the Debian registry (#22854) and
therefore shares some methods. I marked this PR as blocked because it
should be merged after #22854.


![grafik](https://user-images.githubusercontent.com/1666336/227779595-b76163aa-eea1-4a79-9583-775c24ad74e8.png)

---------

Co-authored-by: techknowlogick <techknowlogick@gitea.io>
Co-authored-by: silverwind <me@silverwind.io>
Co-authored-by: Giteabot <teabot@gitea.io>

docs/content/doc/administration/config-cheat-sheet.en-us.md

@@ -1213,6 +1213,7 @@ Task queue configuration has been moved to `queue.task`. However, the below conf
 - `CHUNKED_UPLOAD_PATH`: **tmp/package-upload**: Path for chunked uploads. Defaults to `APP_DATA_PATH` + `tmp/package-upload`
 - `LIMIT_TOTAL_OWNER_COUNT`: **-1**: Maximum count of package versions a single owner can have (`-1` means no limits)
 - `LIMIT_TOTAL_OWNER_SIZE`: **-1**: Maximum size of packages a single owner can use (`-1` means no limits, format `1000`, `1 MB`, `1 GiB`)
+- `LIMIT_SIZE_ALPINE`: **-1**: Maximum size of an Alpine upload (`-1` means no limits, format `1000`, `1 MB`, `1 GiB`)
 - `LIMIT_SIZE_CARGO`: **-1**: Maximum size of a Cargo upload (`-1` means no limits, format `1000`, `1 MB`, `1 GiB`)
 - `LIMIT_SIZE_CHEF`: **-1**: Maximum size of a Chef upload (`-1` means no limits, format `1000`, `1 MB`, `1 GiB`)
 - `LIMIT_SIZE_COMPOSER`: **-1**: Maximum size of a Composer upload (`-1` means no limits, format `1000`, `1 MB`, `1 GiB`)

docs/content/doc/usage/packages/alpine.en-us.md

@@ -0,0 +1,133 @@
+---
+date: "2023-03-25T00:00:00+00:00"
+title: "Alpine Packages Repository"
+slug: "packages/alpine"
+draft: false
+toc: false
+menu:
+  sidebar:
+    parent: "packages"
+    name: "Alpine"
+    weight: 4
+    identifier: "alpine"
+---
+
+# Alpine Packages Repository
+
+Publish [Alpine](https://pkgs.alpinelinux.org/) packages for your user or organization.
+
+**Table of Contents**
+
+{{< toc >}}
+
+## Requirements
+
+To work with the Alpine registry, you need to use a HTTP client like `curl` to upload and a package manager like `apk` to consume packages.
+
+The following examples use `apk`.
+
+## Configuring the package registry
+
+To register the Alpine registry add the url to the list of known apk sources (`/etc/apk/repositories`):
+
+```
+https://gitea.example.com/api/packages/{owner}/alpine/<branch>/<repository>
+```
+
+| Placeholder  | Description |
+| ------------ | ----------- |
+| `owner`      | The owner of the packages. |
+| `branch`     | The branch to use. |
+| `repository` | The repository to use. |
+
+If the registry is private, provide credentials in the url. You can use a password or a [personal access token]({{< relref "doc/development/api-usage.en-us.md#authentication" >}}):
+
+```
+https://{username}:{your_password_or_token}@gitea.example.com/api/packages/{owner}/alpine/<branch>/<repository>
+```
+
+The Alpine registry files are signed with a RSA key which must be known to apk. Download the public key and store it in `/etc/apk/keys/`:
+
+```shell
+curl -JO https://gitea.example.com/api/packages/{owner}/alpine/key
+```
+
+Afterwards update the local package index:
+
+```shell
+apk update
+```
+
+## Publish a package
+
+To publish an Alpine package (`*.apk`), perform a HTTP `PUT` operation with the package content in the request body.
+
+```
+PUT https://gitea.example.com/api/packages/{owner}/alpine/{branch}/{repository}
+```
+
+| Parameter    | Description |
+| ------------ | ----------- |
+| `owner`      | The owner of the package. |
+| `branch`     | The branch may match the release version of the OS, ex: `v3.17`. |
+| `repository` | The repository can be used [to group packages](https://wiki.alpinelinux.org/wiki/Repositories) or just `main` or similar. |
+
+Example request using HTTP Basic authentication:
+
+```shell
+curl --user your_username:your_password_or_token \
+     --upload-file path/to/file.apk \
+     https://gitea.example.com/api/packages/testuser/alpine/v3.17/main
+```
+
+If you are using 2FA or OAuth use a [personal access token]({{< relref "doc/development/api-usage.en-us.md#authentication" >}}) instead of the password.
+You cannot publish a file with the same name twice to a package. You must delete the existing package file first.
+
+The server responds with the following HTTP Status codes.
+
+| HTTP Status Code  | Meaning |
+| ----------------- | ------- |
+| `201 Created`     | The package has been published. |
+| `400 Bad Request` | The package name, version, branch, repository or architecture are invalid. |
+| `409 Conflict`    | A package file with the same combination of parameters exist already in the package. |
+
+## Delete a package
+
+To delete an Alpine package perform a HTTP `DELETE` operation. This will delete the package version too if there is no file left.
+
+```
+DELETE https://gitea.example.com/api/packages/{owner}/alpine/{branch}/{repository}/{architecture}/{filename}
+```
+
+| Parameter      | Description |
+| -------------- | ----------- |
+| `owner`        | The owner of the package. |
+| `branch`       | The branch to use. |
+| `repository`   | The repository to use. |
+| `architecture` | The package architecture. |
+| `filename`     | The file to delete.
+
+Example request using HTTP Basic authentication:
+
+```shell
+curl --user your_username:your_token_or_password -X DELETE \
+     https://gitea.example.com/api/packages/testuser/alpine/v3.17/main/test-package-1.0.0.apk
+```
+
+The server responds with the following HTTP Status codes.
+
+| HTTP Status Code  | Meaning |
+| ----------------- | ------- |
+| `204 No Content`  | Success |
+| `404 Not Found`   | The package or file was not found. |
+
+## Install a package
+
+To install a package from the Alpine registry, execute the following commands:
+
+```shell
+# use latest version
+apk add {package_name}
+# use specific version
+apk add {package_name}={package_version}
+```

docs/content/doc/usage/packages/overview.en-us.md

@@ -27,6 +27,7 @@ The following package managers are currently supported:
 
 | Name | Language | Package client |
 | ---- | -------- | -------------- |
+| [Alpine]({{< relref "doc/usage/packages/alpine.en-us.md" >}}) | - | `apk` |
 | [Cargo]({{< relref "doc/usage/packages/cargo.en-us.md" >}}) | Rust | `cargo` |
 | [Chef]({{< relref "doc/usage/packages/chef.en-us.md" >}}) | - | `knife` |
 | [Composer]({{< relref "doc/usage/packages/composer.en-us.md" >}}) | PHP | `composer` |

docs/content/doc/usage/packages/storage.en-us.md

@@ -9,7 +9,7 @@ menu:
   sidebar:
     parent: "packages"
     name: "Storage"
-    weight: 5
+    weight: 2
     identifier: "storage"
 ---