pdf-gen-fallback-501bcc

PDF Generation Fallback Pattern

When to Use

Apply this pattern when execute_code_sandbox returns opaque or unhelpful errors during PDF, DOCX, or other document generation tasks. This fallback uses run_shell with direct python -c execution for more reliable document generation.

Step-by-Step Procedure

1. Detect Sandbox Failure

If execute_code_sandbox fails during document generation with errors like:

• 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 with python -c and multi-line strings for document generation:

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

Library	Purpose	Import Statement
reportlab	PDF generation	from reportlab.pdfgen import canvas
fpdf2	PDF generation	from fpdf import FPDF
pypdf	PDF manipulation	from pypdf import PdfReader
python-docx	DOCX generation	from docx import Document
xlsxwriter	Excel files	import xlsxwriter