bash function to retry with backoff

with_backoff.sh

function with_backoff {
# http://stackoverflow.com/questions/8350942/how-to-re-run-the-curl-command-automatically-when-the-error-occurs
# by phs
#
# The retry count is given by ATTEMPTS (default 5), the initial backoff
# timeout is given by TIMEOUT in seconds (default 1.)
#
# Successive backoffs double the timeout.

  local max_attempts=${ATTEMPTS-5}
  local timeout=${TIMEOUT-1}
  local attempt=0
  local exitCode=0

  while (( $attempt < $max_attempts ))
  do
    set +e
    "$@"
    exitCode=$?
    set -e

    if [[ $exitCode == 0 ]]
    then
      break
    fi

    echo "Failure! Retrying in $timeout.." 1>&2
    sleep $timeout
    attempt=$(( attempt + 1 ))
    timeout=$(( timeout * 2 ))
  done

  if [[ $exitCode != 0 ]]
  then
    echo "You've failed me for the last time! ($@)" 1>&2
  fi

  return $exitCode
}