1# This file must use Python 1.5 syntax. 2import glob 3import os 4import sys 5 6 7class check_python_version: 8 9 def __init__(self): 10 # The change to prefer 2.4 really messes up any systems which have both 11 # the new and old version of Python, but where the newer is default. 12 # This is because packages, libraries, etc are all installed into the 13 # new one by default. Some things (like running under mod_python) just 14 # plain don't handle python restarting properly. I know that I do some 15 # development under ipython and whenever I run (or do anything that 16 # runs) 'import common' it restarts my shell. Overall, the change was 17 # fairly annoying for me (and I can't get around having 2.4 and 2.5 18 # installed with 2.5 being default). 19 if sys.version_info.major >= 3: 20 try: 21 # We can't restart when running under mod_python. 22 from mod_python import apache 23 except ImportError: 24 self.restart() 25 26 27 PYTHON_BIN_GLOB_STRINGS = ['/usr/bin/python2*', '/usr/local/bin/python2*'] 28 29 30 def find_desired_python(self): 31 """Returns the path of the desired python interpreter.""" 32 # CrOS only ever has Python 2.7 available, so pick whatever matches. 33 pythons = [] 34 for glob_str in self.PYTHON_BIN_GLOB_STRINGS: 35 pythons.extend(glob.glob(glob_str)) 36 return pythons[0] 37 38 39 def restart(self): 40 python = self.find_desired_python() 41 sys.stderr.write('NOTE: %s switching to %s\n' % 42 (os.path.basename(sys.argv[0]), python)) 43 sys.argv.insert(0, '-u') 44 sys.argv.insert(0, python) 45 os.execv(sys.argv[0], sys.argv) 46