feat: add cache argument

cache/cache.go

@@ -0,0 +1,64 @@
+// Copyright 2023 Mikhail Klementev. All rights reserved.
+// Use of this source code is governed by a AGPLv3 license
+// (or later) that can be found in the LICENSE file.
+
+package cache
+
+import (
+	"fmt"
+	"io/ioutil"
+	"net/url"
+	"os"
+	"os/exec"
+
+	"github.com/cavaliergopher/grab/v3"
+	"github.com/rs/zerolog/log"
+
+	"code.dumpstack.io/tools/out-of-tree/config"
+)
+
+var URL string
+
+func unpackTar(archive, destination string) (err error) {
+	// NOTE: If you're change anything in tar command please check also
+	// BSD tar (or if you're using macOS, do not forget to check GNU Tar)
+	// Also make sure that sparse files are extracting correctly
+	cmd := exec.Command("tar", "-Sxf", archive)
+	cmd.Dir = destination + "/"
+
+	log.Debug().Msgf("%v", cmd)
+
+	rawOutput, err := cmd.CombinedOutput()
+	if err != nil {
+		err = fmt.Errorf("%v: %s", err, rawOutput)
+		return
+	}
+
+	return
+}
+
+func DownloadQemuImage(path, file string) (err error) {
+	tmp, err := ioutil.TempDir(config.Dir("tmp"), "out-of-tree_")
+	if err != nil {
+		return
+	}
+	defer os.RemoveAll(tmp)
+
+	fileurl, err := url.JoinPath(URL, file+".tar.gz")
+	if err != nil {
+		return
+	}
+
+	resp, err := grab.Get(tmp, fileurl)
+	if err != nil {
+		err = fmt.Errorf("Cannot download %s. It looks like you need "+
+			"to generate it manually and place it "+
+			"to ~/.out-of-tree/images/. "+
+			"Check documentation for additional information.",
+			fileurl)
+		return
+	}
+
+	err = unpackTar(resp.Filename, path)
+	return
+}

cache/cache_test.go

@@ -0,0 +1,31 @@
+package cache
+
+import (
+	"io/ioutil"
+	"os"
+	"path/filepath"
+	"testing"
+
+	"code.dumpstack.io/tools/out-of-tree/fs"
+)
+
+func TestDownloadQemuImage(t *testing.T) {
+
+	tmp, err := ioutil.TempDir("", "out-of-tree_")
+	if err != nil {
+		return
+	}
+	defer os.RemoveAll(tmp)
+
+	URL = "https://out-of-tree.fra1.digitaloceanspaces.com/1.0.0/"
+	file := "out_of_tree_ubuntu_12__04.img"
+
+	err = DownloadQemuImage(tmp, file)
+	if err != nil {
+		t.Fatal(err)
+	}
+
+	if !fs.PathExists(filepath.Join(tmp, file)) {
+		t.Fatalf("%s does not exist", file)
+	}
+}