internal/rosa/python: url pip wheel helper

This enables a cleaner higher-level helper.

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

internal/rosa/python.go

@@ -1,6 +1,7 @@
 package rosa
 
 import (
+	"path"
 	"slices"
 	"strings"
 
@@ -80,6 +81,25 @@ func init() {
 	}
 }
 
+// newViaPip installs a pip wheel from a url.
+func (t Toolchain) newViaPip(
+	name, version, url, checksum string,
+	extra ...PArtifact,
+) pkg.Artifact {
+	return t.New(name+"-"+version, 0, t.AppendPresets(nil,
+		slices.Concat(P{Python}, extra)...,
+	), nil, nil, `
+pip3 install \
+	--no-index \
+	--prefix=/system \
+	--root=/work \
+	'/usr/src/`+path.Base(url)+`'
+`, pkg.Path(AbsUsrSrc.Append(path.Base(url)), false, pkg.NewHTTPGet(
+		nil, url,
+		mustDecode(checksum),
+	)))
+}
+
 // newViaPip is a helper for installing python dependencies via pip.
 func newViaPip(
 	name, description, version, interpreter, abi, platform, checksum, prefix string,