How to Install Watchdog in Python Step by Step

Watchdog is a Python library for monitoring file system changes. It helps track file creations, modifications, and deletions. This guide will show you how to install and use it.

Prerequisites

Before installing Watchdog, ensure you have Python installed. You can check by running python --version in your terminal.

If you don't have Python, download it from the official website. Also, ensure pip is installed. Pip is Python's package manager.

Installing Watchdog

To install Watchdog, open your terminal or command prompt. Run the following command:

pip install watchdog

This will download and install the latest version of Watchdog. If you encounter issues, check our guide on How To Solve ModuleNotFoundError: No module named in Python.

Verifying the Installation

After installation, verify it works. Open a Python shell and import the module:

import watchdog
print(watchdog.__version__)

If no errors appear, the installation was successful. You should see the version number printed.

Basic Usage of Watchdog

Watchdog monitors file system changes. Here's a simple example to get started.

First, create a Python script. Import the necessary modules:

from watchdog.observers import Observer
from watchdog.events import FileSystemEventHandler

Next, define a custom event handler. This class will react to file changes.

class MyHandler(FileSystemEventHandler):
    def on_modified(self, event):
        print(f'File modified: {event.src_path}')

Now, set up the observer. It will watch a directory for changes.

event_handler = MyHandler()
observer = Observer()
observer.schedule(event_handler, path='.', recursive=True)
observer.start()

Run the script. It will monitor the current directory for changes. Try modifying a file to see the output.

Handling Different Events

Watchdog can handle various events. Here are some common ones:

• on_created: Triggered when a file is created.
• on_deleted: Triggered when a file is deleted.
• on_moved: Triggered when a file is moved.

Update the handler to include these events:

class MyHandler(FileSystemEventHandler):
    def on_created(self, event):
        print(f'File created: {event.src_path}')

    def on_deleted(self, event):
        print(f'File deleted: {event.src_path}')

    def on_moved(self, event):
        print(f'File moved: {event.src_path} to {event.dest_path}')

Now, the script will log all these events. This is useful for logging or automation tasks.

Running the Monitor

To keep the script running, add a try-except block. This ensures the observer stops gracefully.

try:
    while True:
        pass
except KeyboardInterrupt:
    observer.stop()
observer.join()

Run the script again. It will keep monitoring until you press Ctrl+C.

Example Output

Here’s an example of what the output might look like:

File created: ./test.txt
File modified: ./test.txt
File deleted: ./test.txt

This shows the script detecting file changes in real-time.

Advanced Usage

Watchdog can also monitor subdirectories. Set recursive=True when scheduling the observer.

You can also filter events by file type. Check event.is_directory to handle folders separately.

def on_modified(self, event):
    if not event.is_directory:
        print(f'File modified: {event.src_path}')

This ensures only file modifications are logged.

Conclusion

Watchdog is a powerful tool for file system monitoring in Python. It’s easy to install and use. This guide covered the basics, but there’s much more you can do.

For more advanced features, check the official documentation. Happy coding!