Method for searching local files based on thread in python Development,

Method for searching local files based on thread in python Development,

This example describes how to search for local files based on thread in python development. We will share this with you for your reference. The details are as follows:

Let's take a look at the run:

Using multiple threads to handle the search issue, we can find that it is very fast ....

The following is the code:

# A parallelized "find(1)" using the thread module.# This demonstrates the use of a work queue and worker threads.# It really does do more stats/sec when using multiple threads,# although the improvement is only about 20-30 percent.# (That was 8 years ago. In 2002, on Linux, I can't measure# a speedup. :-( )# I'm too lazy to write a command line parser for the full find(1)# command line syntax, so the predicate it searches for is wired-in,# see function selector() below. (It currently searches for files with# world write permission.)# Usage: parfind.py [-w nworkers] [directory] ...# Default nworkers is 4import sysimport getoptimport timeimport osfrom stat import *import _thread as thread# Work queue class. Usage:#  wq = WorkQ()#  wq.addwork(func, (arg1, arg2, ...)) # one or more calls#  wq.run(nworkers)# The work is done when wq.run() completes.# The function calls executed by the workers may add more work.# Don't use keyboard interrupts!class WorkQ:  # Invariants:  # - busy and work are only modified when mutex is locked  # - len(work) is the number of jobs ready to be taken  # - busy is the number of jobs being done  # - todo is locked iff there is no work and somebody is busy  def __init__(self):    self.mutex = thread.allocate()    self.todo = thread.allocate()    self.todo.acquire()    self.work = []    self.busy = 0  def addwork(self, func, args):    job = (func, args)    self.mutex.acquire()    self.work.append(job)    self.mutex.release()    if len(self.work) == 1:      self.todo.release()  def _getwork(self):    self.todo.acquire()    self.mutex.acquire()    if self.busy == 0 and len(self.work) == 0:      self.mutex.release()      self.todo.release()      return None    job = self.work[0]    del self.work[0]    self.busy = self.busy + 1    self.mutex.release()    if len(self.work) > 0:      self.todo.release()    return job  def _donework(self):    self.mutex.acquire()    self.busy = self.busy - 1    if self.busy == 0 and len(self.work) == 0:      self.todo.release()    self.mutex.release()  def _worker(self):    time.sleep(0.00001)   # Let other threads run    while 1:      job = self._getwork()      if not job:        break      func, args = job      func(*args)      self._donework()  def run(self, nworkers):    if not self.work:      return # Nothing to do    for i in range(nworkers-1):      thread.start_new(self._worker, ())    self._worker()    self.todo.acquire()# Main programdef main():  nworkers = 4  #print(getopt.getopt(sys.argv[1:], '-w:'))  opts, args = getopt.getopt(sys.argv[1:], '-w:')  for opt, arg in opts:    if opt == '-w':      nworkers = int(arg)  if not args:    #print(os.curdir)    args = [os.curdir]  wq = WorkQ()  for dir in args:    wq.addwork(find, (dir, selector, wq))  t1 = time.time()  wq.run(nworkers)  t2 = time.time()  sys.stderr.write('Total time %r sec.\n' % (t2-t1))# The predicate -- defines what files we look for.# Feel free to change this to suit your purposedef selector(dir, name, fullname, stat):  # Look for world writable files that are not symlinks  return (stat[ST_MODE] & 0o002) != 0 and not S_ISLNK(stat[ST_MODE])# The find procedure -- calls wq.addwork() for subdirectoriesdef find(dir, pred, wq):  try:    names = os.listdir(dir)  except os.error as msg:    print(repr(dir), ':', msg)    return  for name in names:    if name not in (os.curdir, os.pardir):      fullname = os.path.join(dir, name)      try:        stat = os.lstat(fullname)      except os.error as msg:        print(repr(fullname), ':', msg)        continue      if pred(dir, name, fullname, stat):        print(fullname)      if S_ISDIR(stat[ST_MODE]):        if not os.path.ismount(fullname):          wq.addwork(find, (fullname, pred, wq))# Call the main programmain()

I hope this article will help you with Python programming.