Add verbose logging

Author: tomhollingworth

cmd/merge/go.sum

@@ -12,43 +12,74 @@ import (
 var dir string
 var extensions string
 var output string
+var verbose bool
 
 func init() {
 	flag.StringVar(&dir, "directory", "./path/to/files/", "directory of files to merge")
 	flag.StringVar(&extensions, "extension", ".txt", "the file extension of files to merge. Use comma separation for multiple types.")
 	flag.StringVar(&output, "output", "./output.txt", "the output file name")
+	flag.BoolVar(&verbose, "verbose", false, "verbose logging")
 }
 
 func main() {
-	tmp := make([]byte, 0)
-	directory := os.DirFS(dir)
+
+	if verbose {
+		fmt.Printf("called with directory=%s, extension=%s, output=%s\n", dir, extensions, output)
+	}
 
 	acceptedExtensions := strings.Split(extensions, ",")
 
-	walkErr := fs.WalkDir(directory, ".", func(path string, d fs.DirEntry, err error) error {
-		if d.IsDir() {
+	if verbose {
+		fmt.Printf("accepted extensions: include %s\n", strings.Join(acceptedExtensions, ", "))
+	}
+
+	Merge(dir, acceptedExtensions, output, verbose)
+}
+
+func Merge(d string, fileExtensions []string, outputFilepath string, verboseLogging bool) {
+	directory := os.DirFS(d)
+
+	tmp := make([]byte, 0)
+
+	walkErr := fs.WalkDir(directory, ".", func(path string, entry fs.DirEntry, err error) error {
+		if entry.IsDir() {
+			if verboseLogging {
+				fmt.Printf("skipping directory %s\n", d+path)
+			}
 			return nil
 		}
 
 		if err != nil {
+			if verboseLogging {
+				fmt.Printf("error checking directory %s\n", d+path)
+			}
 			return err
 		}
 
-		if len(acceptedExtensions) != 0 {
+		if len(fileExtensions) != 0 {
 			found := false
-			for _, extension := range acceptedExtensions {
+			for _, extension := range fileExtensions {
 				if strings.HasSuffix(path, extension) {
 					found = true
+					fmt.Printf("found matching file extension %s for %s\n", extension, d+path)
 					break
 				}
 			}
 			if !found {
+				if verboseLogging {
+					fmt.Printf("didn't find matching file extension for %s\n", d+path)
+				}
 				return nil
 			}
+		} else {
+			if verboseLogging {
+				fmt.Println("no extensions to check")
+			}
 		}
 
-		fileBytes, readErr := os.ReadFile(dir + path)
+		fileBytes, readErr := os.ReadFile(d + path)
 		if readErr != nil {
+			fmt.Printf("error reading file %s\n", d+path)
 			return readErr
 		}
 
@@ -57,29 +88,32 @@ func main() {
 	})
 
 	if walkErr != nil {
-		log.Print(walkErr)
+		fmt.Printf("error walking file system %s\n", walkErr)
 	}
 
-	if _, err := os.Stat(output); err == nil {
+	if _, err := os.Stat(outputFilepath); err == nil {
 
-		inputBytes, readErr := os.ReadFile(output)
+		inputBytes, readErr := os.ReadFile(outputFilepath)
 		if readErr != nil {
+			fmt.Printf("didn't find existing file %s\n", outputFilepath)
 			log.Print(err)
 			os.Exit(1)
 		}
 
-		if err := os.WriteFile(output+".old", inputBytes, 0777); err != nil {
+		if err := os.WriteFile(outputFilepath+".old", inputBytes, 0777); err != nil {
 			log.Print(err)
 			os.Exit(1)
 		}
+	} else {
+		fmt.Printf("didn't find existing file %s\n", outputFilepath)
 	}
 
-	err := os.WriteFile(output, tmp, 0777)
+	err := os.WriteFile(outputFilepath, tmp, 0777)
 
 	if err != nil {
 		log.Print(err)
 		os.Exit(1)
 	}
 
-	fmt.Printf("created %s\n", output)
+	fmt.Printf("created %s\n", outputFilepath)
 }