fix: more explicit error handling

Author: jnsgruk

main.go

@@ -52,7 +52,7 @@ type LibationsPageData struct {
 
 // parseTemplates is used to parse templates from the embedded FS, and ensure that the
 // 'StringJoin' function is available to the templates.
-func parseTemplates() *template.Template {
+func parseTemplates() (*template.Template, error) {
 	// Create an fs.FS from the embedded filesystem
 	files, err := fs.Sub(templateFS, "templates")
 	if err != nil {
@@ -62,8 +62,13 @@ func parseTemplates() *template.Template {
 
 	funcMap := template.FuncMap{"StringsJoin": strings.Join}
 	tmpl := template.New("").Funcs(funcMap)
-	tmpl, _ = tmpl.ParseFS(files, "*.html", "icons/*.svg")
-	return tmpl
+
+	tmpl, err = tmpl.ParseFS(files, "*.html", "icons/*.svg")
+	if err != nil {
+		return nil, err
+	}
+
+	return tmpl, nil
 }
 
 // parseRecipes attempts to read and parse recipes either from a path specified at the CLI,
@@ -103,7 +108,11 @@ func libationsMux(drinks []Drink, files fs.FS) *http.ServeMux {
 	// Serve static files from our embedded filesystem using http.Fileserver
 	mux.Handle("/static/", http.StripPrefix("/static/", http.FileServer(http.FS(files))))
 
-	templates := parseTemplates()
+	templates, err := parseTemplates()
+	if err != nil {
+		slog.Error("failed to parse templates from filesystem", "error", err.Error())
+		os.Exit(1)
+	}
 
 	// Render the templates with the drinks/time data.
 	mux.HandleFunc("/", func(w http.ResponseWriter, r *http.Request) {
@@ -196,32 +205,36 @@ func main() {
 	// Create an fs.FS from the embedded filesystem
 	files, err := fs.Sub(staticFS, "static")
 	if err != nil {
-		slog.Error(err.Error())
+		slog.Error("failed to access static files in embedded filesystem", "error", err.Error())
 		os.Exit(1)
 	}
 
 	drinks, err := parseRecipes(*recipesFile)
 	if err != nil {
-		slog.Error(err.Error())
+		slog.Error("failed to parse recipes", "error", err.Error())
 		os.Exit(1)
 	}
 
 	var listener *net.Listener
 	if *local {
 		listener, err = localListener(*addr)
+		if err != nil {
+			slog.Error("failed to create local listener", "error", err.Error())
+			os.Exit(1)
+		}
 	} else {
 		listener, err = tailscaleListener(*hostname, *tsnetLogs)
-	}
-
-	if err != nil {
-		slog.Error(err.Error())
-		os.Exit(1)
+		if err != nil {
+			slog.Error("failed to create tailscale listener", "error", err.Error())
+			os.Exit(1)
+		}
 	}
 
 	mux := libationsMux(drinks, files)
 
 	slog.Info(fmt.Sprintf("starting listener on %s", *addr))
 	if err = http.Serve(*listener, mux); err != nil {
-		slog.Error(err.Error())
+		slog.Error("failed to start http server", "error", err.Error())
+		os.Exit(1)
 	}
 }