Excel Creation via Shell Heredoc Fallback

Overview

When creating Excel files with openpyxl,

execute_code_sandbox

run_shell

When to Use This Skill

• execute_code_sandbox

  fails when importing or using openpyxl
• Sandbox shows errors about missing packages, permissions, or execution restrictions
• You need to create Excel files with advanced formatting (styles, colors, merged cells, formulas)
• Previous sandbox attempts have failed multiple times

Step-by-Step Instructions

Step 1: Attempt Sandbox Execution First

Always try

execute_code_sandbox

from openpyxl import Workbook
from openpyxl.styles import Font, Fill, PatternFill, Alignment

wb = Workbook()
ws = wb.active
ws['A1'] = 'Header'
ws['A1'].font = Font(bold=True)
wb.save('output.xlsx')

Step 2: Detect Sandbox Failure

Watch for these failure indicators:

• ImportError for openpyxl or related modules
• Permission denied errors
• File write failures
• Repeated retry loops without success
• Timeout or resource errors

Step 3: Fall Back to Shell Heredoc

When sandbox fails, switch to

run_shell

python3 << 'EOF'
from openpyxl import Workbook
from openpyxl.styles import Font, Fill, PatternFill, Alignment, Border, Side

# Create workbook
wb = Workbook()
ws = wb.active
ws.title = "Sheet1"

# Add data with formatting
ws['A1'] = 'Name'
ws['B1'] = 'Value'
ws['A1'].font = Font(bold=True, size=14)
ws['B1'].font = Font(bold=True, size=14)

# Add rows
data = [
    ['Item 1', 100],
    ['Item 2', 200],
    ['Item 3', 150],
]

for row_idx, row_data in enumerate(data, start=2):
    for col_idx, value in enumerate(row_data, start=1):
        cell = ws.cell(row=row_idx, column=col_idx, value=value)
        cell.alignment = Alignment(horizontal='center')

# Add formulas if needed
ws['B5'] = '=SUM(B2:B4)'

# Save the file
wb.save('output.xlsx')
print("Excel file created successfully: output.xlsx")
EOF

Step 4: Use run_shell Tool

Execute the heredoc via

run_shell

tool: run_shell
command: python3 << 'EOF'
[from openpyxl code here]
EOF

Step 5: Verify File Creation

After execution, confirm the file was created:

tool: run_shell
command: ls -lh output.xlsx

Check the file size to ensure it's not empty (should be >1KB for typical spreadsheets).

Best Practices

1. Use Single-Quoted Heredoc Delimiter

Always use

<< 'EOF'

2. Include Error Handling

Add try/except blocks to catch and report issues:

try:
    from openpyxl import Workbook
    # ... your code ...
    wb.save('output.xlsx')
    print("SUCCESS: File created")
except Exception as e:
    print(f"ERROR: {e}")
    exit(1)

3. Print Confirmation Messages

Always include print statements that confirm success or report specific errors. This helps debug issues.

4. Use Absolute or Explicit Paths

When saving files, use explicit paths to avoid confusion:

wb.save('./output.xlsx')  # Explicit current directory
# or
wb.save('/workspace/output.xlsx')  # Absolute path

5. Keep Scripts Concise

Heredoc scripts should be focused and not excessively long. If the Excel logic is complex, consider writing a separate

.py

write_file

Advanced Formatting Examples

Cell Styling

from openpyxl.styles import Font, PatternFill, Alignment, Border, Side

# Define styles
bold_font = Font(bold=True, size=12)
header_fill = PatternFill(start_color='4472C4', end_color='4472C4', fill_type='solid')
center_align = Alignment(horizontal='center', vertical='center')
thin_border = Border(
    left=Side(style='thin'),
    right=Side(style='thin'),
    top=Side(style='thin'),
    bottom=Side(style='thin')
)

# Apply to cells
ws['A1'].font = bold_font
ws['A1'].fill = header_fill
ws['A1'].alignment = center_align

Column Width and Row Height

ws.column_dimensions['A'].width = 20
ws.column_dimensions['B'].width = 15
ws.row_dimensions[1].height = 25

Merged Cells

ws.merge_cells('A1:C1')
ws['A1'] = 'Merged Header'
ws['A1'].alignment = Alignment(horizontal='center')

Multiple Sheets

wb.create_sheet(title='Summary')
wb.create_sheet(title='Details')
ws_summary = wb['Summary']
ws_details = wb['Details']

Troubleshooting

pip install openpyxl

run_shell

Comparison: Sandbox vs. Shell Heredoc

Example Complete Workflow

# Step 1: Try sandbox
tool: execute_code_sandbox
code: |
  from openpyxl import Workbook
  wb = Workbook()
  ws = wb.active
  ws['A1'] = 'Test'
  wb.save('test.xlsx')

# Step 2: If that fails, use shell heredoc
tool: run_shell
command: |
  python3 << 'EOF'
  from openpyxl import Workbook
  from openpyxl.styles import Font, PatternFill
  
  wb = Workbook()
  ws = wb.active
  
  ws['A1'] = 'Header'
  ws['A1'].font = Font(bold=True)
  ws['A1'].fill = PatternFill(start_color='FFFF00', fill_type='solid')
  
  wb.save('test.xlsx')
  print("Created: test.xlsx")
  EOF

# Step 3: Verify
tool: run_shell
command: ls -lh test.xlsx