HTTPError: 500 Server Error: INTERNAL SERVER ERROR

Hello everybody :slight_smile:

This is the first time i write a post here, please excuse rookie mistakes; I´ll do my best!
:slight_smile:
When trying to backtest a very simple strategy, I receive the following error message:
‘’
HTTPError: (‘500 Server Error: INTERNAL SERVER ERROR for url: http://houston/zipline/backtests/tst_strategy_III?bundle=usstock-1min&start_date=2017-01-01&end_date=2019-01-01’, {‘status’: ‘error’, ‘msg’: “name ‘null’ is not defined”})
‘’

The flightlog is:
‘’
quantrocket_zipline_1|{
quantrocket_zipline_1| “cells”: [
quantrocket_zipline_1| {
quantrocket_zipline_1| “cell_type”: “code”,
quantrocket_zipline_1| “execution_count”: 2,
quantrocket_zipline_1| “metadata”: {},
quantrocket_zipline_1| “outputs”: [],
quantrocket_zipline_1| “source”: [
quantrocket_zipline_1| “from zipline.api import order, record, symbol\n”,
quantrocket_zipline_1| “\n”,
quantrocket_zipline_1| “\n”,
quantrocket_zipline_1| “def initialize(context):\n”,
quantrocket_zipline_1| " stock_1 = [sid(‘FIBBG002D9R2H9’)]\n",
quantrocket_zipline_1| “\n”,
quantrocket_zipline_1| “\n”,
quantrocket_zipline_1| “def handle_data(context, data):\n”,
quantrocket_zipline_1| " order(stock_1, 10)\n",
quantrocket_zipline_1| " record(AAPL=data.current(stock_1, ‘price’))"
quantrocket_zipline_1| ]
quantrocket_zipline_1| },
quantrocket_zipline_1| {
quantrocket_zipline_1| “cell_type”: “code”,
quantrocket_zipline_1| “execution_count”: null,
quantrocket_zipline_1| “metadata”: {},
quantrocket_zipline_1| “outputs”: [],
quantrocket_zipline_1| “source”: []
quantrocket_zipline_1| }
quantrocket_zipline_1| ],
quantrocket_zipline_1| “metadata”: {
quantrocket_zipline_1| “kernelspec”: {
quantrocket_zipline_1| “display_name”: " Zipline environment",
quantrocket_zipline_1| “language”: “python”,
quantrocket_zipline_1| “name”: “zipline”
quantrocket_zipline_1| },
quantrocket_zipline_1| “language_info”: {
quantrocket_zipline_1| “codemirror_mode”: {
quantrocket_zipline_1| “name”: “ipython”,
quantrocket_zipline_1| “version”: 3
quantrocket_zipline_1| },
quantrocket_zipline_1| “file_extension”: “.py”,
quantrocket_zipline_1| “mimetype”: “text/x-python”,
quantrocket_zipline_1| “name”: “python”,
quantrocket_zipline_1| “nbconvert_exporter”: “python”,
quantrocket_zipline_1| “pygments_lexer”: “ipython3”,
quantrocket_zipline_1| “version”: “3.6.2”
quantrocket_zipline_1| }
quantrocket_zipline_1| },
quantrocket_zipline_1| “nbformat”: 4,
quantrocket_zipline_1| “nbformat_minor”: 4
quantrocket_zipline_1|}
quantrocket_zipline_1|Traceback (most recent call last):
quantrocket_zipline_1| File “sym://qrocket_app_py”, line 738, in post
quantrocket_zipline_1| File “sym://qrocket_qrzipline_backtest_py”, line 167, in backtest_algo
quantrocket_zipline_1| File “/opt/conda/lib/python3.6/site-packages/zipline/algorithm.py”, line 371, in init
quantrocket_zipline_1| exec_(code, self.namespace)
quantrocket_zipline_1| File “tst_strategy_III”, line 23, in
quantrocket_zipline_1|NameError: name ‘null’ is not defined
‘’
Thank you very much in advance for helping!

Have a great day,
Julian

This means you have an undefined variable in your file “tst_strategy_III”, on line 23.

If you’re not familiar, please check out some general resources on how to read a Python traceback:

Hi Brian,

thanks for the response. My problem is that I don´t understand the issue. “Execution_count” seems to be something running in the background and googling it, my impression was that it is supposed to be “Null”.

Could you tell me how to resolve the issue?

Thanks in advance and happy new year!

Best
Julian