feat: boot.img.lz4

cmd/dkl-local-server/upstream.go

@@ -0,0 +1,80 @@
+package main
+
+import (
+	"flag"
+	"io"
+	"log"
+	"net/http"
+	"os"
+	gopath "path"
+	"path/filepath"
+	"time"
+)
+
+var (
+	upstreamURL = flag.String("upstream", "https://direktil.novit.nc/dist", "Upstream server for dist elements")
+)
+
+func (ctx *renderContext) distFetch(path ...string) (outPath string, err error) {
+	outPath = ctx.distFilePath(path...)
+
+	if _, err = os.Stat(outPath); err == nil {
+		return
+	} else if !os.IsNotExist(err) {
+		return
+	}
+
+	subPath := gopath.Join(path...)
+
+	log.Print("need to fetch ", subPath)
+
+	if err = os.MkdirAll(filepath.Dir(outPath), 0755); err != nil {
+		return
+	}
+
+	fullURL := *upstreamURL + "/" + subPath
+
+	resp, err := http.Get(fullURL)
+	if err != nil {
+		return
+	}
+
+	tempOutPath := filepath.Join(filepath.Dir(outPath), "._part_"+filepath.Base(outPath))
+
+	done := make(chan error, 1)
+	go func() {
+		defer resp.Body.Close()
+		defer close(done)
+
+		out, err := os.Create(tempOutPath)
+		if err != nil {
+			done <- err
+			return
+		}
+
+		defer out.Close()
+
+		_, err = io.Copy(out, resp.Body)
+		done <- err
+	}()
+
+wait:
+	select {
+	case <-time.After(10 * time.Second):
+		log.Print("still fetching ", subPath, "...")
+		goto wait
+
+	case err = <-done:
+		if err != nil {
+			log.Print("fetch of ", subPath, " failed: ", err)
+			os.Remove(tempOutPath)
+			return
+		}
+
+		log.Print("fetch of ", subPath, " finished")
+	}
+
+	err = os.Rename(tempOutPath, outPath)
+
+	return
+}