From 1d22902eb0216e1c181fabb9fc445c98afecb3d1 Mon Sep 17 00:00:00 2001
From: Mikhail Klementev <blame@dumpstack.io>
Date: Sat, 13 May 2023 11:04:35 +0000
Subject: [PATCH] feat: download debian cache automatically

---
 cache/cache.go          | 23 +++++++++++++++++++++++
 distro/debian/debian.go |  7 ++++++-
 2 files changed, 29 insertions(+), 1 deletion(-)

diff --git a/cache/cache.go b/cache/cache.go
index 33aab4d..21dad0a 100644
--- a/cache/cache.go
+++ b/cache/cache.go
@@ -10,6 +10,7 @@ import (
 	"net/url"
 	"os"
 	"os/exec"
+	"path/filepath"
 
 	"github.com/cavaliergopher/grab/v3"
 	"github.com/rs/zerolog/log"
@@ -62,3 +63,25 @@ func DownloadQemuImage(path, file string) (err error) {
 	err = unpackTar(resp.Filename, path)
 	return
 }
+
+func DownloadDebianCache(cachePath string) (err error) {
+	tmp, err := ioutil.TempDir(config.Dir("tmp"), "out-of-tree_")
+	if err != nil {
+		return
+	}
+	defer os.RemoveAll(tmp)
+
+	file := filepath.Base(cachePath)
+
+	fileurl, err := url.JoinPath(URL, file)
+	if err != nil {
+		return
+	}
+
+	resp, err := grab.Get(tmp, fileurl)
+	if err != nil {
+		return
+	}
+
+	return os.Rename(filepath.Join(tmp, resp.Filename), cachePath)
+}
diff --git a/distro/debian/debian.go b/distro/debian/debian.go
index 7019bda..fa18ee4 100644
--- a/distro/debian/debian.go
+++ b/distro/debian/debian.go
@@ -8,6 +8,7 @@ import (
 
 	"github.com/rs/zerolog/log"
 
+	"code.dumpstack.io/tools/out-of-tree/cache"
 	"code.dumpstack.io/tools/out-of-tree/config"
 )
 
@@ -121,7 +122,6 @@ func kernelRelease(deb string) (r Release, err error) {
 }
 
 var (
-	CacheURL    string
 	CachePath   string
 	RefetchDays int = 7
 )
@@ -130,6 +130,11 @@ func MatchImagePkg(km config.KernelMask) (pkgs []string, err error) {
 	if CachePath == "" {
 		CachePath = config.File("debian.cache")
 		log.Debug().Msgf("Use default kernels cache path: %s", CachePath)
+
+		err = cache.DownloadDebianCache(CachePath)
+		if err != nil {
+			log.Debug().Msg("No remote cache, will take some time")
+		}
 	} else {
 		log.Debug().Msgf("Debian kernels cache path: %s", CachePath)
 	}