Add a verbose flag which prints more updates while executing. (#26)

Fixes #3

cmd/fetch_attachments.go

@@ -51,6 +51,7 @@ func fetchAttachments(cmd *cobra.Command, args []string) error {
 
 	// Run through all the files in the input archive.
 	for _, file := range r.File {
+		verbosePrintln(fmt.Sprintf("Processing file: %s\n", file.Name))
 
 		// Open the file from the input archive.
 		inReader, err := file.Open()
@@ -98,6 +99,7 @@ func fetchAttachments(cmd *cobra.Command, args []string) error {
 }
 
 func processChannelFile(w *zip.Writer, file *zip.File, inBuf []byte, token string) error {
+	verbosePrintln("This is a 'channels' file. Examining it's contents for attachments.")
 
 	// Parse the JSON of the file.
 	var posts []SlackPost
@@ -152,6 +154,8 @@ func processChannelFile(w *zip.Writer, file *zip.File, inBuf []byte, token strin
 				continue
 			}
 
+			verbosePrintln(fmt.Sprintf("Downloading file %s (%s)", file.Id, file.Name))
+
 			// Fetch the file.
 			req, err := http.NewRequest("GET", downloadUrl, nil)
 			if err != nil {

cmd/fetch_emails.go

@@ -50,6 +50,8 @@ func fetchEmails(cmd *cobra.Command, args []string) error {
 
 	// Run through all the files in the input archive.
 	for _, file := range r.File {
+		verbosePrintln(fmt.Sprintf("Processing file: %s\n", file.Name))
+
 		// Open the file from the input archive.
 		inReader, err := file.Open()
 		if err != nil {
@@ -91,6 +93,8 @@ func fetchEmails(cmd *cobra.Command, args []string) error {
 }
 
 func processUsersJson(output io.Writer, input io.Reader, slackApiToken string) error {
+	verbosePrintln("Found users.json file.")
+
 	// We want to preserve all existing fields in JSON.
 	// By using interface{} (instead of struct), we can avoid describing all
 	// the fields (new ones might be added by Slack devs in the future!) at the cost of
@@ -110,6 +114,8 @@ func processUsersJson(output io.Writer, input io.Reader, slackApiToken string) e
 		return errors.New("Failed to find any users in users.json. Looks like something went wrong.")
 	}
 
+	verbosePrintln("Updating users.json contents with fetched emails.")
+
 	for _, user := range data {
 		// These 'ok's only check for type assertion success.
 		// Map access would return untyped nil,
@@ -136,6 +142,8 @@ func processUsersJson(output io.Writer, input io.Reader, slackApiToken string) e
 }
 
 func fetchUserEmails(token string) (map[string]string, error) {
+	verbosePrintln("Fetching emails from Slack API")
+
 	client := &http.Client{}
 	req, err := http.NewRequest("GET", "https://slack.com/api/users.list", nil)
 	if err != nil {
@@ -171,6 +179,8 @@ func fetchUserEmails(token string) (map[string]string, error) {
 		return nil, errors.New("Unexpected lack of ok=true in Slack API response. Is access token correct?")
 	}
 
+	verbosePrintln("Fetched emails from Slack API. Now building a map of them to process.")
+
 	res := make(map[string]string)
 	for _, user := range data.Members {
 		if user.Id != "" && user.Profile.Email != "" {

cmd/root.go

@@ -7,6 +7,7 @@ import (
 var (
 	inputArchive  string
 	outputArchive string
+	verbose       bool
 )
 
 var rootCmd = &cobra.Command{
@@ -21,6 +22,7 @@ Version: 0.4.0`,
 func init() {
 	rootCmd.PersistentFlags().StringVarP(&inputArchive, "input-archive", "i", "", "the path to the Slack export archive which you wish to augment")
 	rootCmd.PersistentFlags().StringVarP(&outputArchive, "output-archive", "o", "", "the path to which you would like the output archive to be written")
+	rootCmd.PersistentFlags().BoolVarP(&verbose, "verbose", "v", false, "print detailed information about what is happening while the command is executing")
 	rootCmd.MarkPersistentFlagRequired("input-archive")
 	rootCmd.MarkPersistentFlagRequired("output-archive")
 	rootCmd.AddCommand(fetchAttachmentsCmd)

cmd/utils.go

@@ -0,0 +1,7 @@
+package cmd
+
+func verbosePrintln(line string) {
+	if verbose {
+		println(line)
+	}
+}