Move some code under conditionals for better error handling.

main.go

@@ -45,26 +45,29 @@ type ServiceConfig struct {
 func main() {
 	var err error
 	var config Config
-	var systemConfig Config
 
 	// Read user config file
-	file, err := os.ReadFile("goolinux.json")
-	if err != nil {
-		fmt.Println("Cannot read user config file")
-		fmt.Println(err)
-		return
-	}
+	{
+		file, err := os.ReadFile("goolinux.json")
+		if err != nil {
+			fmt.Println("Cannot read user config file")
+			fmt.Println(err)
+			return
+		}
 
-	err = hjson.Unmarshal(file, &config)
-	if err != nil {
-		fmt.Println(err)
-		return
+		err = hjson.Unmarshal(file, &config)
+		if err != nil {
+			fmt.Println(err)
+			return
+		}
 	}
 
 	// Read system "base" config file if it exists
 	if config.System.Base != "" {
+		var systemConfig Config
 		path := "services/" + config.System.Base + ".json"
-		file, err = os.ReadFile(path)
+
+		file, err := os.ReadFile(path)
 		if err != nil {
 			fmt.Println("Cannot read system base config file")
 			fmt.Println(err)
@@ -85,32 +88,38 @@ func main() {
 	for name, service := range config.Services {
 		var b strings.Builder
 		var s ServiceConfig
-		fmt.Printf("Service: %s\n", name)
+
+		// If no provider specified, try system
+		if service.Provider == "" { service.Provider = "system" }
 
 		// Read service config file
-		if service.Provider == "" { service.Provider = "system" }
 		fmt.Fprintf(&b, "services/%s/%s.json", name, service.Provider)
 		c, err := os.ReadFile(b.String())
 		if err != nil {
-			fmt.Println("Unknown service: ", err)
-			return
+			switch err := err.(type) {
+			case *os.PathError:
+				// No system config to merge
+				// Rely solely on the user config
+				fmt.Println("  Warning: No system config for service" + name)
+			default:
+				fmt.Println("Error reading service config: ", err)
+				return
+			}
+		} else {
+			// Parse service config
+			err = hjson.Unmarshal(c, &s)
+			if err != nil {
+				fmt.Println("Error parsing config file")
+				fmt.Println(err)
+				return
+			}
+			mergo.Merge(&s, service, mergo.WithOverride)
+			config.Services[name] = s
+
+			// Add service packages to the global list
+			config.System.Packages = append(config.System.Packages, s.Packages...)
 		}
 
-		// Parse service config
-		err = hjson.Unmarshal(c, &s)
-		if err != nil {
-			fmt.Println("Error parsing config file")
-			fmt.Println(err)
-			return
-		}
-		mergo.Merge(&s, service, mergo.WithOverride)
-		config.Services[name] = s
-
-		fmt.Printf(" %v\n", s)
-
-		// Add service packages to the global list
-		config.System.Packages = append(config.System.Packages, s.Packages...)
-
 		// Generate a config file
 		for _, f := range s.ConfigFiles {
 			var b strings.Builder