Add resume capability and enhanced logging

CHANGES.md

@@ -0,0 +1,120 @@
+# Changes Made to google-takeout-sucks
+
+## Summary
+Modified the download functionality to skip files that have already been downloaded by checking both file existence and file size. Enhanced logging to provide detailed progress information for each file.
+
+## Changes
+
+### File: `internal/download/files.go`
+
+1. **Line 6**: Added `log` package import for logging support
+
+2. **Line 18**: Updated `DownloadFileInput` struct to include logger
+   - Added `infoLog *log.Logger` field to pass logger to download function
+
+3. **Line 23**: Updated `FetchFiles()` function to retrieve file size from Google Drive
+   - Changed: `Fields("nextPageToken, files(id, name)")`
+   - To: `Fields("nextPageToken, files(id, name, size)")`
+   - This ensures we get the file size from Google Drive API
+
+4. **Line 49**: Updated `DownloadWorker()` function signature to accept logger
+   - Added `infoLog *log.Logger` parameter
+   - Passes logger to `downloadFileToDisk()` function
+
+5. **Lines 77-128**: Enhanced `downloadFileToDisk()` function with detailed logging
+   - Added file existence check using `os.Stat()`
+   - Added file size comparison between local and remote files
+   - Skips download if file exists and size matches
+   - Re-downloads if file exists but size doesn't match (handles incomplete downloads)
+   - **New logging statements:**
+     - "Processing file: [filename]" - When starting to process a file
+     - "File found locally: [filename] (local size: X bytes, remote size: Y bytes)" - When file exists
+     - "Skipping file (already complete): [filename]" - When file is already downloaded
+     - "File size mismatch, re-downloading: [filename]" - When file needs re-download
+     - "New file, downloading: [filename] (size: X bytes)" - When file doesn't exist
+     - "Starting download: [filename]" - When download begins
+     - "Download completed: [filename]" - When download finishes
+
+### File: `cmd/download.go`
+
+1. **Line 90**: Updated worker initialization to pass logger
+   - Changed: `go download.DownloadWorker(w, processCh, errCh, resCh, srv, cfg, &wg)`
+   - To: `go download.DownloadWorker(w, processCh, errCh, resCh, srv, cfg, downloadInfoLog, &wg)`
+   - Passes the existing `downloadInfoLog` to each worker
+
+## Behavior
+
+### Before Changes
+- Always downloaded all files, even if they already existed locally
+- Would overwrite existing files
+- Limited logging - only showed when files were saved
+
+### After Changes
+- Checks if file exists locally before downloading
+- Compares local file size with Google Drive file size
+- Only downloads if:
+  - File doesn't exist locally, OR
+  - File exists but size doesn't match (incomplete download)
+- Skips download if file exists and size matches
+- **Detailed logging** shows:
+  - Which file is being processed
+  - Whether file was found locally
+  - File size comparison (local vs remote)
+  - Whether file is being skipped, re-downloaded, or is new
+  - When download starts
+  - When download completes
+
+## Benefits
+- Saves bandwidth by not re-downloading existing files
+- Allows resuming interrupted download sessions
+- Handles incomplete downloads by detecting size mismatches
+- **Enhanced visibility** into download progress with detailed logging
+- Easy troubleshooting with file-by-file status updates
+- No changes to CLI interface - works transparently
+
+## Example Log Output
+
+```
+Processing file: takeout-20230101T120000Z-001.zip
+New file, downloading: takeout-20230101T120000Z-001.zip (size: 2147483648 bytes)
+Starting download: takeout-20230101T120000Z-001.zip
+Download completed: takeout-20230101T120000Z-001.zip
+
+Processing file: takeout-20230101T120000Z-002.zip
+File found locally: takeout-20230101T120000Z-002.zip (local size: 2147483648 bytes, remote size: 2147483648 bytes)
+Skipping file (already complete): takeout-20230101T120000Z-002.zip
+
+Processing file: takeout-20230101T120000Z-003.zip
+File found locally: takeout-20230101T120000Z-003.zip (local size: 1048576 bytes, remote size: 2147483648 bytes)
+File size mismatch, re-downloading: takeout-20230101T120000Z-003.zip
+Starting download: takeout-20230101T120000Z-003.zip
+Download completed: takeout-20230101T120000Z-003.zip
+```
+
+## Testing
+To test the changes:
+
+1. Build the application: `go build`
+2. Run a download: `./google-takeout-sucks download --directoryId=<id> --outDir=<path>`
+3. Interrupt the download partway through
+4. Run the same command again - it should skip already-downloaded files and resume
+5. Check logs (shown in console and in `~/.google_takeout_sucks/logs/download info.log`) - you should see detailed status for each file
+
+## Deployment
+
+### Building
+```bash
+go build
+```
+
+### Installation
+```bash
+go install
+```
+
+Or copy the built binary to your desired location.
+
+### Usage (unchanged)
+```bash
+takeout download --directoryId=<directoryId> --outDir=<absolute/path/to/save/files>
+```

cmd/download.go

@@ -87,7 +87,7 @@ func downloadFiles(cmd *cobra.Command, cfg *download.Config) {
 	// Create workers to download files
 	for w := 1; w <= runtime.NumCPU(); w++ {
 		wg.Add(1)
-		go download.DownloadWorker(w, processCh, errCh, resCh, srv, cfg, &wg)
+		go download.DownloadWorker(w, processCh, errCh, resCh, srv, cfg, downloadInfoLog, &wg)
 	}
 
 	// Wait for all files to be downloaded and saved to disk

internal/download/files.go

@@ -3,6 +3,7 @@ package download
 import (
 	"fmt"
 	"io"
+	"log"
 	"net/http"
 	"os"
 	"path/filepath"
@@ -15,12 +16,13 @@ type DownloadFileInput struct {
 	destination string
 	srv         *drive.Service
 	driveFile   *drive.File
+	infoLog     *log.Logger
 }
 
 func FetchFiles(res *[]*drive.File, token string, srv *drive.Service, cfg *Config) error {
 	q := fmt.Sprintf("'%s' in parents", *cfg.DirectoryId)
 
-	r, err := srv.Files.List().Q(q).PageSize(50).Fields("nextPageToken, files(id, name)").PageToken(token).Do()
+	r, err := srv.Files.List().Q(q).PageSize(50).Fields("nextPageToken, files(id, name, size)").PageToken(token).Do()
 
 	if err != nil {
 		return err
@@ -44,6 +46,7 @@ func DownloadWorker(
 	resCh chan<- string,
 	srv *drive.Service,
 	cfg *Config,
+	infoLog *log.Logger,
 	wg *sync.WaitGroup) {
 
 	defer wg.Done()
@@ -59,6 +62,7 @@ func DownloadWorker(
 			srv:         srv,
 			destination: *cfg.OutDir,
 			driveFile:   driveFile,
+			infoLog:     infoLog,
 		})
 
 		if err != nil {
@@ -71,14 +75,38 @@ func DownloadWorker(
 }
 
 func downloadFileToDisk(input DownloadFileInput) error {
-	// Create the file
+	// Log which file we're working on
+	input.infoLog.Printf("Processing file: %s", input.driveFile.Name)
+
+	// Check if file already exists and matches the remote file size
 	absdst := filepath.Join(input.destination, input.driveFile.Name)
+	if fileInfo, err := os.Stat(absdst); err == nil {
+		// File exists, check if size matches
+		input.infoLog.Printf("File found locally: %s (local size: %d bytes, remote size: %d bytes)",
+			input.driveFile.Name, fileInfo.Size(), input.driveFile.Size)
+
+		if fileInfo.Size() == input.driveFile.Size {
+			// File already exists with same size, skip download
+			input.infoLog.Printf("Skipping file (already complete): %s", input.driveFile.Name)
+			return nil
+		}
+		// File exists but size doesn't match, will re-download
+		input.infoLog.Printf("File size mismatch, re-downloading: %s", input.driveFile.Name)
+	} else {
+		// File doesn't exist
+		input.infoLog.Printf("New file, downloading: %s (size: %d bytes)", input.driveFile.Name, input.driveFile.Size)
+	}
+
+	// Create the file
 	out, err := os.Create(absdst)
 	if err != nil {
 		return fmt.Errorf("unable to create file %s: %w", input.destination, err)
 	}
 	defer out.Close()
 
+	// Log start of download
+	input.infoLog.Printf("Starting download: %s", input.driveFile.Name)
+
 	// Fetch the file
 	resp, err := input.srv.Files.Get(input.driveFile.Id).Download()
 	if err != nil {
@@ -93,5 +121,8 @@ func downloadFileToDisk(input DownloadFileInput) error {
 	if err != nil {
 		return fmt.Errorf("unable to copy response to destination: %w", err)
 	}
+
+	// Log completion
+	input.infoLog.Printf("Download completed: %s", input.driveFile.Name)
 	return nil
 }