musicindex: cache tarballs by default

overridable with the -r command line option

.gitignore

@@ -0,0 +1 @@
+records

main.go

@@ -16,11 +16,13 @@ const version = "0-pre"
 
 var addr *string
 var port *uint16
+var regenerate *bool
 var showVersion *bool
 
 func main() {
 	addr = getopt.String('a', "0.0.0.0")
 	port = getopt.Uint16('p', 8000)
+	regenerate = getopt.Bool('r')
 	showVersion = getopt.Bool('V')
 	if err := getopt.Getopt(nil); err != nil {
 		util.Die(err.Error())
@@ -33,7 +35,7 @@ func main() {
 
 	args := getopt.Args()
 	if len(args) != 1 {
-		fmt.Fprintf(os.Stderr, "usage: %s [-V] [-a address] [-p port] directory\n", os.Args[0])
+		fmt.Fprintf(os.Stderr, "usage: %s [-rV] [-a address] [-p port] directory\n", os.Args[0])
 		os.Exit(1)
 	}
 
@@ -42,7 +44,7 @@ func main() {
 	log.Printf("This is records %s\n", version)
 	log.Println("https://git.baxters.nz/jeremy/records")
 
-	musicindex.Init(mediaDir)
+	musicindex.Init(mediaDir, *regenerate)
 
 	var artistCount, albumCount, songCount int
 	artistCount = len(musicindex.Artists())

musicindex/index.go

@@ -2,7 +2,6 @@ package musicindex
 
 import (
 	"errors"
-	"fmt"
 	"io/fs"
 	"log"
 	"os"
@@ -58,13 +57,26 @@ func indexArtists() {
 		util.Die("%s", err.Error())
 	}
 
-	err = os.RemoveAll(TempDir)
-	if err != nil {
-		util.Die("cannot remove temporary directory %s: %s", TempDir, err.Error())
+	if (regenerateTarballs) {
+		err = os.RemoveAll(TempDir)
+		if err != nil {
+			util.Die("cannot remove temporary directory %s: %s", TempDir, err.Error())
+		}
 	}
-	err = os.Mkdir(TempDir, 0711)
+
+	f, err := os.Stat(TempDir)
 	if err != nil {
-		util.Die("cannot make temporary directory %s: %s", TempDir, err.Error())
+		err = os.Mkdir(TempDir, 0711)
+		if err != nil {
+			util.Die("cannot make temporary directory %s: %s", TempDir,
+				err.Error())
+		}
+		log.Println("generating new tarball index")
+	} else {
+		if !f.IsDir() {
+			util.Die("cannot make temporary directory %s: %s", TempDir,
+				"not a directory")
+		}
 	}
 
 	artists = make(map[string]Artist)
@@ -148,42 +160,32 @@ func indexAlbum(artist *Artist, albumName, albumDir string) (a Album, err error)
 	slices.Sort(tracks)
 	a.TrackFiles = tracks
 
+	generate := false
 	hash := util.HashOf(a.Artist.Name + "::" + a.Name)
-	path := TempDir + "/" + hash
+	a.Tarball = TempDir + "/" + hash
 
-	if _, err = os.Stat(path); errors.Is(err, os.ErrNotExist) {
-		a.Tarball = path
-	} else if err == nil {
-		a.Tarball = ""
-		for i := range 9 {
-			if _, err = os.Stat(fmt.Sprintf("%s.%d", path, i)); err == nil {
-				continue
-			} else if errors.Is(err, os.ErrNotExist) {
-				a.Tarball = path
-			} else {
-				err = errors.New("cannot create tarball in filesystem: " +
-					err.Error())
-				return
-			}
+	if _, err = os.Stat(a.Tarball); errors.Is(err, os.ErrNotExist) {
+		// if the file isn't there we definitely want to generate one
+		generate = true
+	} else { // if the file exists or if it's some other error
+		if regenerateTarballs {
+			// not sure why this is here since we deleted the whole
+			// directory beforehand but let's try overwrite it anyway
+			generate = true
 		}
-		if len(a.Tarball) == 0 {
-			err = errors.New("cannot create tarball in filesystem; " +
-				"please clean out " + TempDir)
-			return
-		}
-	} else {
-		err = errors.New("cannot create tarball in filesystem: " + err.Error())
-		return
 	}
 
-	a.Tarball = path
-	err = targz.Compress(a.Directory(), a.Tarball)
-	if err != nil {
-		return
+	if generate {
+		err = targz.Compress(a.Directory(), a.Tarball)
+		if err != nil {
+			a.Tarball = ""
+			return
+		}
 	}
 
 	tarball, err := os.Stat(a.Tarball)
 	if err != nil {
+		a.Tarball = ""
 		return
 	}
 	a.TarballSize = tarball.Size()

musicindex/musicindex.go

@@ -34,20 +34,23 @@ var artists map[string]Artist
 var coverFileExtension string
 var defaultCoverFile string
 var mediaDir string
+var regenerateTarballs bool
 var trackFileExtension string
 
-func Init(path string) {
-	InitWith(path, ".flac", "cover.jpg", ".jpg")
+func Init(path string, regenerate bool) {
+	InitWith(path, regenerate, ".flac", "cover.jpg", ".jpg")
 }
 
-func InitWith(path, mediaExtension, coverFile, coverExtension string) {
+func InitWith(path string, regenerate bool,
+	mediaExtension, coverFile, coverExtension string) {
 	if initialised {
 		return
 	}
 
 	mediaDir = path
-	trackFileExtension = mediaExtension
 	defaultCoverFile = coverFile
+	regenerateTarballs = regenerate
+	trackFileExtension = mediaExtension
 	coverFileExtension = coverExtension
 
 	assertAccessTo(mediaDir)