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Domain

domain

Summary

The Expenses Service domain layer: business knowledge, models, ports, enrichment and fetch pipelines, with zero I/O.

The domain package holds the rules of the Expenses Service: pydantic models, abstract ports, and the enrichment/fetch pipeline logic. No module here touches the network, the database, or user-facing HTTP; all external effects flow through ports implemented by the infrastructure layer and injected at the composition root.

Installation

Install the Expenses Service with its development tooling:

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pip install -e ".[dev]"

Quick start

Resolve the lazily cached entity enrichment pipeline and run it over a minimal state payload:

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```python
from domain.enrichment.entity.pipeline import get_entity_pipeline

pipeline = get_entity_pipeline()
result = pipeline.enrich({"candidate": {"flags": []}, "tags": []})
```

Core concepts

  • Three-layer architecture: interface (OpenAPI/FastAPI routes) → domain (business rules, zero I/O) → infra (MongoDB, SSE, OCR, LLM providers). Each layer imports only the one below it.
  • Models: pydantic schemas that validate the data the domain moves, from fetch requests to enriched expenses.
  • Ports: abstract contracts the domain needs from the outside world; infrastructure implementations are injected via hexa.build.
  • Enrichment: rule-driven pipelines (entity + tags) that turn raw descriptions into payees and tags.
  • Fetch pipeline: extracts expenses from pdf, email, xlsx, csv and LlamaParse sources, then enriches and persists them.

Notes

Guarantees:

  • Domain code performs zero I/O; persistence, OCR, LLM calls and streaming happen only through injected ports and adaptors.

Lifecycle:

  • The package is compiled statically by doc-forge from its GSDFC docstrings; source remains the single source of truth.