simple watchfolder daemon. using mysql to tag files as processed, which isn't perfect. can be changed to redis, mongo or memcache easily.

gistfile1.py

#!/usr/bin/env python

import os
import sys
import datetime
import time
import logging

try:
    import MySQLdb as db
except ImportError, e:
    logging.warning(e)

connection = None
watchfolder = "watchfolder" #relative to where script is running
donefolder = "donefolder" #relative to where script is running

def diff(a, b):
    b = set(b)
    return [aa for aa in a if aa not in b]

def watchmenow():

    logging.basicConfig(filename="watchfolder.log", level=logging.DEBUG)
    logging.info("starting watchfolder worker")
    logging.warning(os.getpid())
    lastfilelist = []

    try:
        connection = db.connect("DBHOST", "DBUSER", "DBPASS", "DBNAME");
        connection.autocommit(True)
        cursor = connection.cursor()
    except db.Error, e:
        logging.warning(e)
        sys.exit()

    while True:
        try:
                
            # find new files, ie the difference between the sets
            filelist = os.listdir(watchfolder)
            newfiles = diff(filelist, lastfilelist);

            for newfile in newfiles:

                # which file
                logging.info("found new file: %s", (newfile))

                # move file to vhosted folder
                os.rename(os.path.join(watchfolder, newfile), os.path.join(donefolder, newfile))
                logging.info("moving file to vhost: %s", (newfile))

                # tag as ready in db
                sql = "UPDATE filtered_images SET status = 1 WHERE filename = %s"
                cursor.execute(sql, (newfile))
                logging.info("updated mysql status for file: %s", (newfile))


            # remove from filelist
            lastfilelist = filelist

        except Exception, e:
            logging.warning(e)
            time.sleep(10)
            continue

        time.sleep(0.7)

if __name__ == "__main__":
    watchmenow()