htest/utils.py

   1 #!/usr/bin/env python3
   2
   3 #
   4 # Copyright (c) 2018 Vojtech Horky
   5 # All rights reserved.
   6 #
   7 # Redistribution and use in source and binary forms, with or without
   8 # modification, are permitted provided that the following conditions
   9 # are met:
  10 #
  11 # - Redistributions of source code must retain the above copyright
  12 #   notice, this list of conditions and the following disclaimer.
  13 # - Redistributions in binary form must reproduce the above copyright
  14 #   notice, this list of conditions and the following disclaimer in the
  15 #   documentation and/or other materials provided with the distribution.
  16 # - The name of the author may not be used to endorse or promote products
  17 #   derived from this software without specific prior written permission.
  18 #
  19 # THIS SOFTWARE IS PROVIDED BY THE AUTHOR ``AS IS'' AND ANY EXPRESS OR
  20 # IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE IMPLIED WARRANTIES
  21 # OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE ARE DISCLAIMED.
  22 # IN NO EVENT SHALL THE AUTHOR BE LIABLE FOR ANY DIRECT, INDIRECT,
  23 # INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL DAMAGES (INCLUDING, BUT
  24 # NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS OR SERVICES; LOSS OF USE,
  25 # DATA, OR PROFITS; OR BUSINESS INTERRUPTION) HOWEVER CAUSED AND ON ANY
  26 # THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT LIABILITY, OR TORT
  27 # (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY OUT OF THE USE OF
  28 # THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF SUCH DAMAGE.
  29 #
  30
  31 import time
  32 import logging
  33 import shlex
  34
  35 def retries(n=None, interval=2, timeout=None, message="Operation timed-out (too many retries)", name=""):
  36     """
  37     To be used in for-loops to try action multiple times.
  38     Throws exception on time-out.
  39     """
  40
  41     if (n is None) and (timeout is None):
  42         raise Exception("Specify either n or timeout for retries")
  43
  44     if name != "":
  45         name = "-" + name
  46     logger = logging.getLogger("rtr" + name)
  47
  48     if timeout is None:
  49         timeout = n * interval
  50     remaining = timeout
  51     n = 0
  52     while remaining > 0:
  53         logger.debug("remaining={}, n={}, interval={}, \"{}\"".format(
  54             remaining, n, interval, message))
  55         remaining = remaining - interval
  56         n = n + 1
  57         yield n
  58         time.sleep(interval)
  59     logger.debug("timed-out, n={}, \"{}\"".format(n, message))
  60     raise Exception(message)
  61
  62 def format_command(cmd):
  63     """
  64     Escape shell command given as list of arguments.
  65     """
  66     escaped = [shlex.quote(i) for i in cmd]
  67     return ' '.join(escaped)
  68
  69 def format_command_pipe(pipe):
  70     """
  71     Escape shell pipe given as list of list of arguments.
  72     """
  73     escaped = [format_command(i) for i in pipe]
  74     return ' | '.join(escaped)
  75