internal/rosa: python pip helper

Fuse requires pytest which depends on many packages. This helper eases the pain of packaging them.

Signed-off-by: Ophestra <cat@gensokyo.uk>

internal/rosa/python.go

@@ -1,6 +1,7 @@
 package rosa
 
 import (
+	"slices"
 	"strings"
 
 	"hakurei.app/internal/pkg"
@@ -64,6 +65,26 @@ make DESTDIR=/work install
 }
 func init() { artifactsF[Python] = Toolchain.newPython }
 
+// newViaPip is a helper for installing python dependencies via pip.
+func (t Toolchain) newViaPip(
+	name, version, abi, platform, checksum, prefix string,
+	extra ...pkg.Artifact,
+) pkg.Artifact {
+	wname := name + "-" + version + "-py3-" + abi + "-" + platform + ".whl"
+	return t.New(name+"-"+version, false, slices.Concat([]pkg.Artifact{
+		t.Load(Python),
+	}, extra), nil, nil, `
+pip3 install \
+	--no-index \
+	--prefix=/system \
+	--root=/work \
+	/usr/src/`+wname+`
+`, pkg.Path(AbsUsrSrc.Append(wname), false, pkg.NewHTTPGet(
+		nil, prefix+wname,
+		mustDecode(checksum),
+	)))
+}
+
 func (t Toolchain) newSetuptools() pkg.Artifact {
 	const (
 		version  = "80.10.1"