checksize.go: utility for size check of metatdata

checksize.go

@@ -0,0 +1,111 @@
+// +build ignore
+
+package main
+
+import (
+	"archive/tar"
+	"compress/gzip"
+	"flag"
+	"fmt"
+	"io"
+	"io/ioutil"
+	"log"
+	"os"
+
+	"github.com/vbatts/tar-split/tar/asm"
+	"github.com/vbatts/tar-split/tar/storage"
+)
+
+var (
+	flCleanup = flag.Bool("cleanup", true, "cleanup tempfiles")
+)
+
+func main() {
+	flag.Parse()
+
+	for _, arg := range flag.Args() {
+		fh, err := os.Open(arg)
+		if err != nil {
+			log.Fatal(err)
+		}
+		defer fh.Close()
+		fi, err := fh.Stat()
+		if err != nil {
+			log.Fatal(err)
+		}
+		fmt.Printf("inspecting %q (size %dk)\n", fh.Name(), fi.Size()/1024)
+
+		packFh, err := ioutil.TempFile("", "packed.")
+		if err != nil {
+			log.Fatal(err)
+		}
+		defer packFh.Close()
+		if *flCleanup {
+			defer os.Remove(packFh.Name())
+		}
+
+		sp := storage.NewJsonPacker(packFh)
+		fp := asm.NewDiscardFilePutter()
+		dissam, err := asm.NewInputTarStream(fh, sp, fp)
+		if err != nil {
+			log.Fatal(err)
+		}
+
+		var num int
+		tr := tar.NewReader(dissam)
+		for {
+			_, err = tr.Next()
+			if err != nil {
+				if err == io.EOF {
+					break
+				}
+				log.Fatal(err)
+			}
+			num++
+			if _, err := io.Copy(ioutil.Discard, tr); err != nil {
+				log.Fatal(err)
+			}
+		}
+		fmt.Printf(" -- number of files: %dk\n", num)
+
+		if err := packFh.Sync(); err != nil {
+			log.Fatal(err)
+		}
+
+		fi, err = packFh.Stat()
+		if err != nil {
+			log.Fatal(err)
+		}
+		fmt.Printf(" -- size of metadata uncompressed: %dk\n", fi.Size()/1024)
+
+		gzPackFh, err := ioutil.TempFile("", "packed.gz.")
+		if err != nil {
+			log.Fatal(err)
+		}
+		defer gzPackFh.Close()
+		if *flCleanup {
+			defer os.Remove(gzPackFh.Name())
+		}
+
+		gzWrtr := gzip.NewWriter(gzPackFh)
+
+		if _, err := packFh.Seek(0, 0); err != nil {
+			log.Fatal(err)
+		}
+
+		if _, err := io.Copy(gzWrtr, packFh); err != nil {
+			log.Fatal(err)
+		}
+		gzWrtr.Close()
+
+		if err := gzPackFh.Sync(); err != nil {
+			log.Fatal(err)
+		}
+
+		fi, err = gzPackFh.Stat()
+		if err != nil {
+			log.Fatal(err)
+		}
+		fmt.Printf(" -- size of gzip compressed metadata: %dk\n", fi.Size()/1024)
+	}
+}