testing/web-platform/tests/tools/docker/retry.py

   1 #!/usr/bin/env python3
   2 import argparse
   3 import subprocess
   4 import time
   5 import sys
   6
   7
   8 def get_args() -> argparse.ArgumentParser:
   9     parser = argparse.ArgumentParser()
  10     parser.add_argument("--delay", action="store", type=float, default=3, help="Initial delay before retry, in seconds")
  11     parser.add_argument("--count", action="store", type=int, default=5, help="Total number of tries")
  12     parser.add_argument("--factor", action="store", type=float, default=2, help="Exponential backoff factor")
  13     parser.add_argument("cmd", nargs=argparse.REMAINDER)
  14     return parser
  15
  16
  17 def log(value: str) -> None:
  18     print(value)
  19     sys.stdout.flush()
  20
  21
  22 def main() -> None:
  23     args = get_args().parse_args()
  24
  25     if not args.cmd:
  26         log("No command supplied")
  27         sys.exit(1)
  28
  29     retcode = None
  30
  31     for n in range(args.count):
  32         try:
  33             log("Running %s [try %d/%d]" % (" ".join(args.cmd), (n+1), args.count))
  34             subprocess.check_call(args.cmd)
  35         except subprocess.CalledProcessError as e:
  36             retcode = e.returncode
  37         else:
  38             log("Command succeeded")
  39             retcode = 0
  40             break
  41
  42         if args.factor == 0:
  43             wait_time = (n+1) * args.delay
  44         else:
  45             wait_time = args.factor**n * args.delay
  46         if n < args.count - 1:
  47             log("Command failed, waiting %s seconds to retry" % wait_time)
  48             time.sleep(wait_time)
  49         else:
  50             log("Command failed, out of retries")
  51
  52     sys.exit(retcode)
  53
  54
  55 if __name__ == "__main__":
  56     main()