minor refactor

main.go

@@ -20,13 +20,15 @@ import (
 )
 
 var (
-	imagesDir   string
-	collageDir  string
-	localAssets bool
-)
+	imagesDir      string
+	collageDir     string
+	localAssets    bool
+	collageNameGen *nameGen
+	imagesDirFs    fs.FS
 
-//go:embed web/*
-var webFS embed.FS
+	// go:embed web/*
+	webFS embed.FS
+)
 
 func main() {
 	flag.StringVar(&imagesDir, "images-dir", "images", "Sets the images dir")
@@ -34,8 +36,9 @@ func main() {
 	flag.BoolVar(&localAssets, "local-assets", false, "Serve local assets for testing")
 
 	flag.Parse()
-	nameGen := NewNameGen()
-	imagesDirFs := os.DirFS(imagesDir)
+
+	collageNameGen = NewNameGen()
+	imagesDirFs = os.DirFS(imagesDir)
 	imagesURLPath := "images"
 	collagesPath := "collages"
 
@@ -67,19 +70,18 @@ func main() {
 		body, err := io.ReadAll(r.Body)
 		if err != nil {
 			slog.Error("failed to read request body", "error", err)
+			w.WriteHeader(http.StatusInternalServerError)
 			return
 		}
 		if err := json.Unmarshal(body, &collageReq); err != nil {
 			slog.Error("failed to unmarshal json request", "error", err)
+			w.WriteHeader(http.StatusInternalServerError)
 			return
 		}
-		collageFile := fmt.Sprintf("collage-%s.jpg", nameGen.Next())
-		out, err := os.Create(path.Join(collageDir, collageFile))
+		collageFile, err := MakeCollage(&collageReq)
 		if err != nil {
-			slog.Error("failed to create collage output file", "error", err)
-		}
-		if err := collage.Make(collageReq, imagesDirFs, out); err != nil {
 			slog.Error("failed to make collage", "error", err)
+			w.WriteHeader(http.StatusInternalServerError)
 			return
 		}
 		w.Write([]byte(collageFile))
@@ -116,4 +118,17 @@ func (n *nameGen) Next() string {
 	return fmt.Sprintf("%s-%d", n.prefix, n.counter.Add(1))
 }
 
+func MakeCollage(req *collage.Request) (string, error) {
+	collageFile := fmt.Sprintf("collage-%s.jpg", collageNameGen.Next())
+	out, err := os.Create(path.Join(collageDir, collageFile))
+	if err != nil {
+		return "", fmt.Errorf("failed to create collage output file, err: %w", err)
+		// slog.Error("failed to create collage output file", "error", err)
+	}
+	if err := collage.Make(req, imagesDirFs, out); err != nil {
+		return "", fmt.Errorf("failed to make collage, err: %w", err)
+	}
+	return collageFile, nil
+}
+
 // curl -D - --json @req.json http://localhost:8767/make-collage