CODEWITHSUNDEEP
pythonwatchdogpython-watchdog
k5man001
k5man001

Reputation: 107

How to use Watchdog

Using watchdog, I want it to look for an updated file in some directory, in the event of that updated file it grabs the file name and runs a specific script with the file name and sends the output to a different directory as a txt file. When the text file appears in the new directory, somehow get the name of the file and set it as a variable for analysis.

EX:

First directory /path/to/first/dir/2017/04/27/nfcapd.20170427 <- New File (Notice, not a txt file)

Script is ran to obtain data in that file below by using above file name

nfdump - r nfcapd.20170427 > home/users/rmaestas/nfcapd.20170427.txt

File name is stored into a variable to be used with code

updated = 'nfcapd.21070427.txt’

filename = ('home/users/rmaestas/') #<-- insert 'updated in directory'
with open(filename, 'r') as infile:    
    next(infile) #Skips the first row, first row is not data.
    for line in infile:#read every line       
        if "Summary:" in line:#End of the data, last4 lines are a summary which won't be needed.
            break
        print(line.split()[4].rsplit(':', 1)[0])

#more code...

Upvotes: 0

Views: 2663

Answers (1)

Farai Gandiya
Farai Gandiya

Reputation: 79

What you need to do is to create a class which inherits one of the file handler's and override the on_modified method which will be called when a file is updated, like so

class CustomFileEventHandler(FileSystemHandler):
    def on_modified(self, event):
        file_name = event.src_path #get's the path of the modified file
        with open(file_name, "r") as infile, open("path/to/file.txt", "w") as result:
            #call your function which should return a string
            result.write(function output) #instead of print

There's no need to append 'home/users/rmaestas' since .src_path will give you the full path of the file.

With your overridden FileSystemHandler, you then need to set up the Observer which will actually do the monitoring which is similar to the example given in watchdog's documentation

event_handler = CustomFileEventHandler()
observer = Observer()
observer.schedule(event_handler, "path/to/dir", recursive=False)
observer.start()
try:
    while True:
        time.sleep(1)
except KeyboardInterrupt:
    observer.stop()
observer.join()

Upvotes: 3

Related Questions