reliable-script-execution

# Reliable Script Execution When executing Python code via shell commands, avoid inline heredoc execution which can fail unpredictably with 'unknown error'. Use this two-step file-first approach for more reliable script execution. ## Problem Direct heredoc Python execution like: ```bash python3 << 'EOF' # complex code here EOF ``` Can fail with 'unknown error', especially when: - Script contains multiple lines or complex logic - Special characters or quotes are present - Working directory context matters ## Solution: File-First Approach ### Step 1: Write Python Script to File Use `write_file` to save your Python code to a `.py` file: ``` write_file(path="./temp_script.py", content=""" import json data = {"key": "value"} print(json.dumps(data)) """) ``` ### Step 2: Execute via Shell Use `run_shell` with explicit working directory: ``` run_shell(command="python3 ./temp_script.py", timeout=60) ``` ### Step 3: Clean Up (Optional) Remove temporary files after execution: ``` run_shell(command="rm ./temp_script.py") ``` ## Complete Example **Task**: Generate a JSON report with calculations ``` # Step 1: Write the script write_file( path="./generate_report.py", content=""" import json from datetime import datetime revenue = 500000.00 expenses = 379577.06 net_income = revenue - expenses report = { "generated": datetime.now().isoformat(), "revenue": revenue, "expenses": expenses, "net_income": net_income } print(json.dumps(report, indent=2)) """ ) # Step 2: Execute run_shell(command="python3 ./generate_report.py", timeout=60) # Step 3: Clean up run_shell(command="rm ./generate_report.py") ``` ## Best Practices 1. **Use descriptive filenames**: Name scripts according to their purpose (e.g., `calculate_pnl.py`, `transform_data.py`) 2. **Set appropriate timeouts**: For data processing scripts, use longer timeouts (60-300 seconds) 3. **Specify working directory**: If the script depends on relative paths, include `cd /path && python3 script.py` 4. **Handle errors gracefully**: Check shell output for errors and retry if needed 5. **Clean up temporary files**: Don't leave `.py` files cluttering the workspace unless they need to persist ## When to Use This Pattern - Executing multi-line Python code via shell - Scripts with complex string handling or special characters - When heredoc execution has failed previously - Any scenario where reliability matters more than brevity ## Anti-Pattern to Avoid Do NOT rely on heredoc for production-critical scripts: ```bash # Unreliable - may fail with 'unknown error' python3 << 'EOF' # Your code here EOF ``` Use file-first approach instead for consistent, debuggable execution.