fi
    # shellcheck disable=SC2181
    if [[ $? == 0 ]]; then
      break
    fi
    if ! grep -Eq "${failureRegex}" "${tmpFile}"; then
      fail "Unexpected failure"
    fi
    if [[ $n -lt $max ]]; then
      ((n++))
      echo "Command failed. Attempt $n/$max:"
    else
      fail "The command has failed after $n attempts."
    fi
  done
}

  // Valid operators are In, NotIn, Exists, DoesNotExist. Gt, and Lt.
  optional string operator = 2;

  // An array of string values. If the operator is In or NotIn,
  // the values array must be non-empty. If the operator is Exists or DoesNotExist,
  // the values array must be empty. If the operator is Gt or Lt, the values
  // array must have a single element, which will be interpreted as an integer.

function log() {
  echo -e "$(date -u '+%Y-%m-%dT%H:%M:%S.%NZ')\t$*"
}

function retry() {
  local n=1
  local max=5
  local delay=5
  while true; do
    "$@" && break
    if [[ $n -lt $max ]]; then
      ((n++))
      log "Command failed. Attempt $n/$max:"
      sleep $delay;
    else
      log "The command has failed after $n attempts."  >&2
      return 2
    fi
  done
}