PythonAnywhere运行pylivetrader脚本遇yaml.load无Loader告警，求安全运行方法

Hey there! Let's tackle that YAMLLoadWarning you're seeing when running pylivetrader on PythonAnywhere. The warning is right to flag this—using yaml.load() without specifying a safe loader is risky because it can execute arbitrary code from the YAML file, which is a security hazard.

Here are a couple of safe, actionable solutions to fix this:

Solution 1: Run via a custom Python script (recommended) #

Instead of using the pylivetrader command line tool directly, write a small wrapper script that loads your YAML config safely before passing it to pylivetrader. This way you have full control over how the config is parsed.

Create a file named run_strategy.py with this code:

import yaml
from pylivetrader import run

# Safely load the backend config using yaml.safe_load()
with open('config.yaml', 'r') as config_file:
    backend_config = yaml.safe_load(config_file)

# Execute your strategy with the safely loaded config
run('bb.py', backend_config=backend_config)

Then run this script from bash instead of the original command:

python run_strategy.py

This bypasses the unsafe yaml.load() call in pylivetrader's command line tool entirely, and you won't see the warning anymore.

Solution 2: Modify pylivetrader's source code (if you have access) #

If you prefer to keep using the original pylivetrader command, you can update the part of the code that loads the YAML config to use a safe loader.

1. First, find where pylivetrader is installed. If you're using a virtual environment (which you should be!), run:

   pip show pylivetrader
   

   Look for the Location field to get the path to the package files.

2. Navigate to that directory and find the file that handles backend config loading. Typically this is in pylivetrader/backend/__init__.py or a similar path.

3. Search for lines that use yaml.load(). You'll see something like:

   with open(config_path) as f:
       config = yaml.load(f)
   

4. Replace that with either:

   # Option A: Use safe_load directly
   with open(config_path) as f:
       config = yaml.safe_load(f)
   

   Or:

   # Option B: Explicitly specify the SafeLoader
   with open(config_path) as f:
       config = yaml.load(f, Loader=yaml.SafeLoader)
   

5. Save the file, and your original pylivetrader command will now load the config safely without the warning.

Temporary workaround (not recommended long-term) #

If you just need to suppress the warning temporarily (while you implement one of the above solutions), you can set the PYTHONWARNINGS environment variable when running the command:

PYTHONWARNINGS="ignore:calling yaml.load" pylivetrader run-f bb.py --backend-config config.yaml

Note: This doesn't fix the underlying security issue—it just hides the warning, so use this only as a short-term stopgap.

内容的提问来源于stack exchange，提问作者Felipe Cunha