Often in development we want to activate a set of commands when a file system. We can use a python library watchdog for this.
Installation
To install watchdog we can use pip like most of python library
:::shell
pip install watchdog
Setup
A simple program that keeps watch on changes in a folder recursively, means each files in subfolder as well is the follwing
#!python
import os
import sys
import time
from watchdog.observers import Observer
from watchdog.events import PatternMatchingEventHandler
class MyHandler(PatternMatchingEventHandler):
patterns = ["*.py", "*.md"]
def process(self, event):
"""
event.event_type
'modified' | 'created' | 'moved' | 'deleted'
event.is_directory
True | False
event.src_path
path/to/observed/file
"""
# the file will be processed there
print(event.src_path, event.event_type)
os.system("write your command here.")
def on_modified(self, event):
self.process(event)
def on_created(self, event):
self.process(event)
if __name__ == '__main__':
args = sys.argv[1:]
path=args[0] if args else '.'
observer = Observer()
observer.schedule(MyHandler(), path, recursive=True)
observer.start()
try:
while True:
time.sleep(1)
except KeyboardInterrupt:
observer.stop()
observer.join()
Save the above script in a file watcher.py in root of project. Now activate the watcher simply by
:::shell
python watcher.py [optional path of directory]
Now whenever any file mentioned in patterns will change, the command in process function will executed automatically.