#!/bin/bash -eu

# The parentheses inside the {} is to scope the exported variables inside a subshell in the function
until_it_works(){(
  export cmd="$1"
  export on_error="${2:-}"
  export max_tries="${3:-10}"

  export tries=1
  until [[ $tries -ge $max_tries || $(exit ${exit_status:-1}) ]]; do
    exit_status=0
    bash -euc "$cmd" || exit_status=$?
    if $(exit $exit_status); then break; fi
    echo "Try #$tries of $max_tries failed with status $exit_status."
    bash -c "$on_error"
    ((++tries))
  done
  if ! $(exit $exit_status); then echo "Try #$tries of $max_tries failed with status $exit_status.".; fi
  return $exit_status
)}

tests=0
# simple success
((++tests)); echo -e "\n""Beginning test $tests"
until_it_works "true" "sleep 1"
echo test $tests returned $?

# simple failure
((++tests)); echo -e "\n""Beginning test $tests"
set +e
until_it_works "false foo" "" 4
echo test $tests returned $?
set -e

# delayed success and using exported variables in the script
((++tests)); echo -e "\n""Beginning test $tests"
until_it_works 'echo tries:$tries; [[ $tries -ge 2 ]];' 'date; sleep 1' 5
echo test $tests returned $?

# Get rid of the wrapper parentheses and you'll get a different result
[[ -n ${tries:-} ]] && echo tries carried over and is $tries || echo tries did not carry over

# vim: ts=2 sts=2 sw=2 cul