1# Copyright 2015 gRPC authors. 2# 3# Licensed under the Apache License, Version 2.0 (the "License"); 4# you may not use this file except in compliance with the License. 5# You may obtain a copy of the License at 6# 7# http://www.apache.org/licenses/LICENSE-2.0 8# 9# Unless required by applicable law or agreed to in writing, software 10# distributed under the License is distributed on an "AS IS" BASIS, 11# WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied. 12# See the License for the specific language governing permissions and 13# limitations under the License. 14"""Helper to watch a (set) of directories for modifications.""" 15 16import os 17import time 18from six import string_types 19 20 21class DirWatcher(object): 22 """Helper to watch a (set) of directories for modifications.""" 23 24 def __init__(self, paths): 25 if isinstance(paths, string_types): 26 paths = [paths] 27 self._done = False 28 self.paths = list(paths) 29 self.lastrun = time.time() 30 self._cache = self._calculate() 31 32 def _calculate(self): 33 """Walk over all subscribed paths, check most recent mtime.""" 34 most_recent_change = None 35 for path in self.paths: 36 if not os.path.exists(path): 37 continue 38 if not os.path.isdir(path): 39 continue 40 for root, _, files in os.walk(path): 41 for f in files: 42 if f and f[0] == '.': continue 43 try: 44 st = os.stat(os.path.join(root, f)) 45 except OSError as e: 46 if e.errno == os.errno.ENOENT: 47 continue 48 raise 49 if most_recent_change is None: 50 most_recent_change = st.st_mtime 51 else: 52 most_recent_change = max(most_recent_change, 53 st.st_mtime) 54 return most_recent_change 55 56 def most_recent_change(self): 57 if time.time() - self.lastrun > 1: 58 self._cache = self._calculate() 59 self.lastrun = time.time() 60 return self._cache 61