python-heredoc-fallback

Python Heredoc Fallback for Code Execution

When to Use

Use this pattern when execute_code_sandbox fails with e2b initialization errors, sandbox connection issues, or other execution environment problems. This is especially reliable for file generation tasks.

Core Pattern

Instead of execute_code_sandbox, run Python code directly in the shell using a heredoc:

python3 << 'EOF'
# Your Python code here
import sys
print("Python code executing in shell")
EOF

Key Syntax Rules

1. Use single-quoted EOF (<< 'EOF') to prevent shell variable expansion within the Python code
2. No indentation before EOF - the closing delimiter must be at the start of the line
3. Install packages first if needed, before the Python heredoc block

Common Use Cases

1. Matplotlib Graph Generation

python3 << 'EOF'
import matplotlib.pyplot as plt
import pandas as pd

# Load data
data = pd.read_excel('input.xlsx')

# Create visualization
plt.figure(figsize=(10, 6))
plt.plot(data['x'], data['y'])
plt.xlabel('X Label')
plt.ylabel('Y Label')
plt.title('Graph Title')
plt.savefig('output_graph.png', dpi=300, bbox_inches='tight')
plt.close()

print("Graph saved successfully")
EOF

2. Python-docx Document Creation

pip install python-docx -q

python3 << 'EOF'
from docx import Document
from docx.shared import Inches, Pt
from docx.enum.text import WD_ALIGN_PARAGRAPH

doc = Document()

# Add title
title = doc.add_heading('Document Title', 0)
title.alignment = WD_ALIGN_PARAGRAPH.CENTER

# Add sections
doc.add_heading('Section 1', level=1)
doc.add_paragraph('Content for section 1.')

# Add table
table = doc.add_table(rows=3, cols=3)
table.style = 'Table Grid'

# Save document
doc.save('output.docx')
print("Document created successfully")
EOF

3. General File Operations

python3 << 'EOF'
import json
import os

# Read input file
with open('input.json', 'r') as f:
    data = json.load(f)

# Process data
result = {'processed': True, 'items': len(data)}

# Write output
with open('output.json', 'w') as f:
    json.dump(result, f, indent=2)

print(f"Processed {result['items']} items")
EOF

Best Practices

1. Install dependencies first: Run pip install package-name -q before the Python block if packages aren't guaranteed to be available
2. Verify file paths: Files are read from and written to the current working directory
3. Add print statements: Include progress/output messages to verify execution succeeded
4. Close resources: Explicitly close matplotlib figures and file handles
5. Handle errors gracefully: Add try/except blocks for production code

Troubleshooting

Issue	Solution
Module not found	Add pip install <module> -q before Python block
File not found	Verify file exists in current directory with ls
Permission denied	Check file permissions and directory write access
Syntax errors	Ensure proper Python indentation within heredoc

Advantages Over execute_code_sandbox

• No initialization overhead - runs immediately in existing shell
• Persistent environment - maintains state across multiple commands
• Direct file system access - no sandbox isolation issues
• Full system Python - access to all installed packages
• Reliable for large files - no sandbox size restrictions