---
id: T01
parent: S04
milestone: M002
provides:
  - export/ package with ChangeRequestEntry model and flatten_to_entries()
  - export_xlsx() with default and custom template modes
  - ExportError exception in hierarchy
  - fpdf2 dependency (for T02)
key_files:
  - src/policyfoundry/export/__init__.py
  - src/policyfoundry/export/models.py
  - src/policyfoundry/export/change_request.py
  - src/policyfoundry/exceptions.py
key_decisions:
  - COLUMN_MAP dict for case-insensitive template header matching — supports both space-separated and underscore-separated variants
  - Metadata section in rows 1-5 (Generated, Run ID, Source Type, Total Rules, blank separator) with header at row 6
  - Missing proposal for a decision is skipped gracefully rather than erroring
patterns_established:
  - export/ package structure with models.py for flattening and change_request.py for file generation
  - format_endpoints/format_port_range as reusable display helpers
  - ExportError with error_code (XLSX_EXPORT_FAILED, TEMPLATE_LOAD_FAILED) and details dict
observability_surfaces:
  - ExportError carries error_code, details dict (output_path, template_path, rule_count), and original exception as __cause__
duration: 25m
verification_result: passed
completed_at: 2026-03-15
blocker_discovered: false
---

# T01: Export package with ChangeRequestEntry model and xlsx export

**Created export/ package with ChangeRequestEntry flattening model, format helpers, and export_xlsx() supporting both default styled workbooks and user-provided template fill.**

## What Happened

Added fpdf2 to pyproject.toml dependencies. Added ExportError to exceptions.py following the established hierarchy pattern.

Created `export/models.py` with `ChangeRequestEntry` (Pydantic BaseModel), `format_endpoints()` handling CIDRs/is_any/sg-id/tags/empty, `format_port_range()` handling single/range/None, and `flatten_to_entries()` that reconstructs typed models via `ExcelPipelineResult.from_state()`, indexes proposals by id, and filters SKIP decisions.

Created `export/change_request.py` with `export_xlsx()` — default mode writes metadata section (rows 1–5), styled header row (bold white on blue fill), and data rows with proportional column widths. Template mode loads user workbook, scans row 1 for case-insensitive column name matches via COLUMN_MAP, finds the first empty row, and fills matched columns only. Both paths wrap errors as ExportError with appropriate error_code.

## Verification

- `pytest tests/test_export/test_models.py -v` — 13 passed (format_endpoints: 6 cases, format_port_range: 3 cases, flatten_to_entries: 4 cases)
- `pytest tests/test_export/test_xlsx_export.py -v` — 11 passed (default: 5, template: 2, empty: 2, errors: 2)
- `npx pyright src/policyfoundry/export/` — 0 errors, 3 warnings (openpyxl missing type stubs — pre-existing)
- `pytest tests/ -x -q` — 588 passed (baseline 564 + 24 new)

**Slice-level verification status (T01):**
- ✅ `pytest tests/test_export/test_models.py -v`
- ✅ `pytest tests/test_export/test_xlsx_export.py -v`
- ⏳ `pytest tests/test_export/test_pdf_export.py -v` — T02 scope
- ✅ `npx pyright src/policyfoundry/export/` — 0 errors
- ✅ `pytest tests/ -x -q` — 588 passed

## Diagnostics

- `ExportError.error_code` distinguishes XLSX_EXPORT_FAILED vs TEMPLATE_LOAD_FAILED
- `ExportError.details` carries output_path, template_path, rule_count for debugging
- `ExportError.__cause__` preserves the original exception for chained tracebacks

## Deviations

None.

## Known Issues

None.

## Files Created/Modified

- `pyproject.toml` — added fpdf2>=2.8 dependency
- `src/policyfoundry/exceptions.py` — added ExportError(PolicyFoundryError)
- `src/policyfoundry/export/__init__.py` — package init with public API re-exports
- `src/policyfoundry/export/models.py` — ChangeRequestEntry, format_endpoints, format_port_range, flatten_to_entries
- `src/policyfoundry/export/change_request.py` — export_xlsx() with default and template modes
- `tests/test_export/__init__.py` — package init
- `tests/test_export/conftest.py` — shared fixtures (sample_excel_state, sample_excel_state_empty)
- `tests/test_export/test_models.py` — 13 tests for models and flattening
- `tests/test_export/test_xlsx_export.py` — 11 tests for xlsx export
