python-shell-fallback

# Python Shell Fallback When `execute_code_sandbox` fails for Python code that depends on external libraries, use `run_shell` with a heredoc Python script as a reliable fallback. The shell environment typically has better access to installed packages and system configuration than the sandbox. ## When to Use This Pattern Apply this skill when: - `execute_code_sandbox` returns errors related to missing libraries (e.g., `ModuleNotFoundError`) - The code requires packages that may not be installed in the sandbox environment - You need PDF generation, data visualization, or other library-heavy operations - Previous sandbox execution attempts have failed with import errors ## How to Implement ### Step 1: Identify the Failure Check if the sandbox error indicates a library/dependency issue: - `ModuleNotFoundError: No module named 'xxx'` - `ImportError: cannot import name 'xxx'` - Similar package-related errors ### Step 2: Convert to Shell Execution Rewrite the code execution using `run_shell` with a heredoc: ```bash python3 << 'EOF' # Your Python code here import library_name # ... rest of code EOF ``` ### Step 3: Execute via run_shell Call `run_shell` with the heredoc Python script: ``` command: python3 << 'EOF' import reportlab from reportlab.lib.pagesizes import letter from reportlab.pdfgen import canvas # Your library-dependent code here c = canvas.Canvas("output.pdf", pagesize=letter) c.drawString(100, 750, "Hello World") c.save() EOF ``` ## Example: PDF Generation Fallback **Sandbox attempt (fails):** ```python # execute_code_sandbox call fails with: # ModuleNotFoundError: No module named 'reportlab' ``` **Shell fallback (works):** ```bash python3 << 'EOF' from reportlab.lib.pagesizes import letter from reportlab.pdfgen import canvas c = canvas.Canvas("legal_memo.pdf", pagesize=letter) c.setTitle("Legal Memorandum") c.drawString(100, 750, "CONFIDENTIAL LEGAL MEMORANDUM") c.save() print("PDF created successfully") EOF ``` ## Best Practices 1. **Use quoted heredoc (`<< 'EOF'`)** - Prevents variable expansion, keeping Python code intact 2. **Verify output** - Check stdout/stderr from `run_shell` to confirm success 3. **Handle file paths** - Ensure output files are written to accessible directories 4. **Test incrementally** - For complex scripts, test in smaller chunks first 5. **Include error handling** - Add try/except blocks to capture issues gracefully ## Alternative: Inline Python Command For simple one-liners or short scripts: ```bash python3 -c "import reportlab; print(reportlab.__version__)" ``` ## Troubleshooting If shell execution also fails: - Check if Python3 is available: `which python3` - Verify package installation: `pip3 list | grep package_name` - Try `python` instead of `python3` (some systems differ) - Consider installing the package: `pip3 install package_name`