PDF Generation Fallback Pattern

When to Use

Apply this pattern when

execute_code_sandbox

run_shell

python -c

Step-by-Step Procedure

1. Detect Sandbox Failure

If

execute_code_sandbox

• Opaque runtime errors
• Missing library errors that don't resolve with import statements
• Silent failures with no output

Proceed to the fallback approach.

2. Check Library Availability

Before generating documents, verify the required Python libraries are available in the shell environment:

python -c "import reportlab; print('OK')" 2>&1 || echo "reportlab missing"
python -c "import fpdf; print('OK')" 2>&1 || echo "fpdf missing"
python -c "import pypdf; print('OK')" 2>&1 || echo "pypdf missing"
python -c "import docx; print('OK')" 2>&1 || echo "python-docx missing"

3. Install Missing Libraries (If Needed)

If a library is missing, install it via pip:

pip install reportlab fpdf2 pypdf python-docx

4. Execute Document Generation via run_shell

Use

run_shell

python -c

python -c "
from reportlab.lib.pagesizes import letter
from reportlab.pdfgen import canvas

c = canvas.Canvas('output.pdf', pagesize=letter)
c.drawString(100, 750, 'Document Title')
c.drawString(100, 700, 'Content here')
c.save()
print('SUCCESS: PDF created')
"

For DOCX files:

python -c "
from docx import Document

doc = Document()
doc.add_heading('Document Title', 0)
doc.add_paragraph('Content here')
doc.save('output.docx')
print('SUCCESS: DOCX created')
"

5. Include Explicit Error Handling

Always wrap generation code with try/except for clear error reporting:

python -c "
try:
    from reportlab.lib.pagesizes import letter
    from reportlab.pdfgen import canvas
    
    c = canvas.Canvas('output.pdf', pagesize=letter)
    c.drawString(100, 750, 'Content')
    c.save()
    print('SUCCESS')
except ImportError as e:
    print(f'MISSING_LIBRARY: {e}')
    exit(1)
except Exception as e:
    print(f'GENERATION_ERROR: {e}')
    exit(1)
"

6. Verify Output File

After generation, confirm the file was created and is valid:

ls -la output.pdf
file output.pdf
test -f output.pdf && echo "File exists" || echo "File missing"

Complete Example Workflow

# Step 1: Check and install library
python -c "import reportlab" 2>&1 || pip install reportlab

# Step 2: Generate PDF with error handling
python -c "
try:
    from reportlab.lib.pagesizes import letter
    from reportlab.pdfgen import canvas
    
    c = canvas.Canvas('report.pdf', pagesize=letter)
    c.setFont('Helvetica', 12)
    c.drawString(100, 750, 'Surveillance Report')
    c.drawString(100, 700, 'Generated via fallback pattern')
    c.save()
    print('SUCCESS: report.pdf created')
except Exception as e:
    print(f'ERROR: {e}')
    exit(1)
"

# Step 3: Verify
test -f report.pdf && echo "Verification: PASSED" || echo "Verification: FAILED"

Why This Works

• Direct Execution:

  run_shell

  with

  python -c

  bypasses sandbox limitations that may affect document generation libraries
• Explicit Errors: Try/except blocks provide actionable error messages instead of opaque failures
• Environment Control: Shell execution gives more control over the Python environment and library paths
• Verification: Explicit file checks confirm success rather than assuming it

Common Libraries

from reportlab.pdfgen import canvas

from fpdf import FPDF

from pypdf import PdfReader

from docx import Document

import xlsxwriter