sources: Add Alpaquita downloader

Signed-off-by: Valery Ushakov <valery.ushakov@bell-sw.com>

doc/reference/source.md

@@ -19,6 +19,7 @@ source:
 The `downloader` field defines a downloader which pulls a rootfs image which will be used as a starting point.
 It needs to be one of
 
+* `alpaquita-http`
 * `alpinelinux-http`
 * `alt-http`
 * `apertis-http`
@@ -52,6 +53,7 @@ The `keyserver` defaults to `hkps.pool.sks-keyservers.net` if none is provided.
 The `variant` field is only used in a few distributions and defaults to `default`.
 Here's a list downloaders and their possible variants:
 
+* `alpaquita-http`: `musl`, `glibc`
 * `centos-http`: `minimal`, `netinstall`, `LiveDVD`
 * `debootstrap`: `default`, `minbase`, `buildd`, `fakechroot`
 * `ubuntu-http`: `default`, `core`

shared/definition.go

@@ -358,6 +358,7 @@ func (d *Definition) Validate() error {
 
 	validDownloaders := []string{
 		"almalinux-http",
+		"alpaquita-http",
 		"alpinelinux-http",
 		"alt-http",
 		"apertis-http",

sources/alpaquita-http.go

@@ -0,0 +1,75 @@
+package sources
+
+import (
+	"crypto/sha512"
+	"fmt"
+	"path/filepath"
+
+	"github.com/lxc/distrobuilder/shared"
+)
+
+type alpaquita struct {
+	common
+}
+
+func (s *alpaquita) Run() error {
+	baseURL, fname, err := s.getMiniroot(s.definition)
+	if err != nil {
+		return err
+	}
+
+	var fpath string
+	tarballURL := baseURL + fname
+	if s.definition.Source.SkipVerification {
+		fpath, err = s.DownloadHash(s.definition.Image,
+			tarballURL, "", nil)
+		if err != nil {
+			return err
+		}
+	} else {
+		fpath, err = s.DownloadHash(s.definition.Image,
+			tarballURL, tarballURL+".sha512", sha512.New())
+		if err != nil {
+			return err
+		}
+	}
+
+	tarballLocal := filepath.Join(fpath, fname)
+	s.logger.WithField("file", tarballLocal).Info("Unpacking image")
+
+	err = shared.Unpack(tarballLocal, s.rootfsDir)
+	if err != nil {
+		return err
+	}
+
+	return nil
+}
+
+// Sample URLs (or with "latest" instead of date):
+//
+//	https://packages.bell-sw.com/alpaquita/musl/stream/releases/x86_64/alpaquita-minirootfs-stream-241231-musl-x86_64.tar.gz
+//	https://packages.bell-sw.com/alpaquita/glibc/23/releases/aarch64/alpaquita-minirootfs-23-241231-glibc-aarch64.tar.gz
+func (s *alpaquita) getMiniroot(definition shared.Definition) (string, string, error) {
+	// default server
+	if s.definition.Source.URL == "" {
+		s.definition.Source.URL = "https://packages.bell-sw.com"
+	}
+
+	// require explicit variant
+	if s.definition.Image.Variant == "default" {
+		return "", "", fmt.Errorf("Alpaquita requires explicitly specified variant")
+	}
+
+	base := fmt.Sprintf("%s/alpaquita/%s/%s/releases/%s/",
+		s.definition.Source.URL,
+		s.definition.Image.Variant,
+		s.definition.Image.Release,
+		s.definition.Image.ArchitectureMapped)
+
+	fname := fmt.Sprintf("alpaquita-minirootfs-%s-latest-%s-%s.tar.gz",
+		s.definition.Image.Release,
+		s.definition.Image.Variant,
+		s.definition.Image.ArchitectureMapped)
+
+	return base, fname, nil
+}

sources/source.go

@@ -25,6 +25,7 @@ type Downloader interface {
 
 var downloaders = map[string]func() downloader{
 	"almalinux-http":       func() downloader { return &almalinux{} },
+	"alpaquita-http":       func() downloader { return &alpaquita{} },
 	"alpinelinux-http":     func() downloader { return &alpineLinux{} },
 	"alt-http":             func() downloader { return &altLinux{} },
 	"apertis-http":         func() downloader { return &apertis{} },