office-stencil 0.1.0

A reusable Office document template render engine for DOCX, XLSX, and PPTX.

Stencil

Stencil is a Python render engine for reusable Office document templates.

It is designed for workflows where a .docx, .xlsx, or .pptx template contains placeholders, loops, and conditionals, and application data fills the template to produce a finished Office document or PDF.

stencil render invoice.docx data.json --output invoice.pdf

The project starts with DOCX because it is the fastest path to a useful internal tool. XLSX and PPTX are planned as separate format engines behind the same public API.

Status

Pre-alpha DOCX MVP.

What exists now:

• uv-compatible Python package metadata
• Python >=3.12
• stencil import package
• render() API for DOCX templates
• stencil render CLI command for JSON data
• DOCX-first roadmap in local ignored docs

What does not exist yet:

• Stable public API
• PDF conversion worker
• XLSX rendering
• PPTX rendering

Naming

The product, import package, and CLI command are named stencil.

The PyPI distribution name is currently office-stencil because stencil is already taken on PyPI by an old package.

[project]
name = "office-stencil"

[project.scripts]
stencil = "stencil.cli:app"

API

from stencil import render

document = render(
    template_path="invoice.docx",
    data={
        "customer": "Acme",
        "line_items": [
            {"description": "Implementation", "amount": 1200},
        ],
    },
    output_format="docx",
)

Phase 1 supports DOCX input and DOCX output only. The exact API may change while the project is pre-alpha.

CLI

stencil render invoice.docx data.json --output invoice.docx

The CLI reads a top-level JSON object from the data file and writes the rendered document bytes to the output path.

PDF output is planned for a later phase.

Example

See examples/ for a runnable DOCX example with:

• examples/templates/invoice.docx
• examples/data/invoice.json
• examples/templates/styled-status-report.docx
• examples/data/status-report.json

uv sync --dev
uv run stencil render examples/templates/invoice.docx examples/data/invoice.json --output examples/out/invoice.docx
uv run stencil render examples/templates/styled-status-report.docx examples/data/status-report.json --output examples/out/styled-status-report.docx

Roadmap

1. Foundation and proof of shape
2. DOCX MVP
3. PDF conversion and reliability
4. Internal package polish
5. XLSX engine
6. PPTX engine
7. Optional service layer and operations

The detailed local roadmap lives in docs/, which is intentionally ignored by git because it is personal planning material.

Dependencies

Runtime dependencies:

• jinja2: template expressions, conditionals, and loops
• docxtpl: DOCX rendering for the first production milestone
• lxml: Office XML parsing and manipulation
• openpyxl: XLSX workbook inspection and future spreadsheet support
• typer: CLI framework

Optional API dependencies:

• fastapi: future HTTP service layer
• uvicorn[standard]: ASGI server for the optional API

Optional worker dependencies:

• rq: lightweight Redis-backed queue option
• celery: larger distributed worker option
• redis: queue/backend client

Development dependencies:

• pytest: test runner
• pytest-cov: coverage reporting
• ruff: linting and import sorting
• mypy: static type checking

External system dependency:

• LibreOffice / soffice: planned conversion engine for PDF output

Local Development

This repo uses uv, but dependencies have not been installed yet.

Install dependencies when ready:

uv sync --dev

Run tests:

uv run pytest

Run linting:

uv run ruff check .

Run type checking:

uv run mypy

Publishing

The repo includes a GitHub Actions workflow at .github/workflows/publish.yml.

It publishes to PyPI when changes land on main:

1. Check out the repo.
2. Install uv.
3. Set up Python 3.12.
4. Install dependencies with uv sync --dev.
5. Run tests with uv run pytest.
6. Run linting with uv run ruff check ..
7. Build the package with uv build.
8. Publish with the PYPI_API_TOKEN GitHub Actions secret.

One-time PyPI token setup:

• Create or use the PyPI project named office-stencil.
• Create a PyPI API token. Prefer a project-scoped token for office-stencil after the first release exists.
• Add the token to GitHub as an Actions secret named PYPI_API_TOKEN.
• The publish workflow uses user: __token__ and password: ${{ secrets.PYPI_API_TOKEN }}.

PyPI requires every upload to have a new version. Before merging a feature branch into main, update the version in pyproject.toml.

Dependabot

The repo includes .github/dependabot.yml.

Dependabot checks weekly for:

• uv dependency updates from pyproject.toml
• GitHub Actions updates from .github/workflows/

Dependabot will open pull requests. Those PRs should go through the same CI and branch-protection rules as feature branches.

Design Notes

Office files are zipped XML packages, but each format has different failure modes.

• DOCX can split template tags across Word text runs.
• XLSX often stores text in shared strings, so naive replacement can mutate unrelated cells.
• PPTX repeated slides require cloning slide XML, relationships, presentation ordering, and content type entries.
• PDF conversion through LibreOffice needs timeouts, retries, cleanup, and worker isolation.

Stencil should stay milestone-driven: ship a reliable DOCX engine first, then use real needs to decide when XLSX, PPTX, and service infrastructure are worth the extra complexity.

License

MIT. See LICENSE.