padelnomics/.claude/CLAUDE.md

CLAUDE.md — Padelnomics

This file tells Claude Code how to work in this repository.

Project Overview

Padelnomics is a SaaS application built with Quart (async Python), HTMX, and SQLite.

It includes a full data pipeline:

External APIs → extract → landing zone → SQLMesh transform → DuckDB → web app

Packages (uv workspace):

• web/ — Quart + HTMX web application (auth, billing, dashboard)

• extract/padelnomics_extract/ — data extraction to local landing zone

• transform/sqlmesh_padelnomics/ — 3-layer SQL transformation (staging → foundation → serving)

• src/padelnomics/ — CLI utilities, export_serving helper

Skills: invoke these for domain tasks

Working on extraction or transformation?

Use the data-engineer skill for:

• Designing or reviewing SQLMesh model logic
• Adding a new data source (extract + staging model)
• Performance tuning DuckDB queries
• Data modeling decisions (dimensions, facts, aggregates)
• Understanding the 3-layer architecture

/data-engineer  (or ask Claude to invoke it)

Working on the web app UI or frontend?

Use the frontend-design skill for UI components, templates, or dashboard layouts.

Working on payments or subscriptions?

Use the paddle-integration skill for billing, webhooks, and subscription logic.

Key commands

# Install all dependencies
uv sync --all-packages

# Lint & format
ruff check .
ruff format .

# Run tests
uv run pytest tests/ -v

# Dev server
./scripts/dev_run.sh

# Extract data
LANDING_DIR=data/landing uv run extract

# SQLMesh plan + run (from repo root)
uv run sqlmesh -p transform/sqlmesh_padelnomics plan
uv run sqlmesh -p transform/sqlmesh_padelnomics plan prod

# Export serving tables (run after SQLMesh)
DUCKDB_PATH=local.duckdb SERVING_DUCKDB_PATH=analytics.duckdb \
    uv run python -m padelnomics.export_serving

Architecture documentation

Topic	File
Extraction patterns, state tracking, adding new sources	extract/padelnomics_extract/README.md
3-layer SQLMesh architecture, materialization strategy	transform/sqlmesh_padelnomics/README.md
Two-file DuckDB architecture (SQLMesh lock isolation)	src/padelnomics/export_serving.py docstring

Pipeline data flow

data/landing/
  ├── overpass/{year}/{month}/courts.json.gz
  ├── eurostat/{year}/{month}/urb_cpop1.json.gz
  └── playtomic/{year}/{month}/tenants.json.gz

data/lakehouse.duckdb       ← SQLMesh exclusive (staging → foundation → serving)

analytics.duckdb            ← serving tables only, web app read-only
  └── serving.*             ← atomically replaced by export_serving.py

Backup & disaster recovery

Data	Tool	Target	Frequency
app.db (auth, billing)	Litestream	R2 padelnomics/app.db	Continuous (WAL)
.state.sqlite (extraction state)	Litestream	R2 padelnomics/state.sqlite	Continuous (WAL)
data/landing/ (JSON.gz files)	rclone sync	R2 padelnomics/landing/	Every 30 min (systemd timer)
lakehouse.duckdb, analytics.duckdb	N/A (derived)	Re-run pipeline	On demand

Recovery:

# App database (auto-restored by Litestream container on startup)
litestream restore -config /etc/litestream.yml /app/data/app.db

# Extraction state (auto-restored by Litestream container on startup)
litestream restore -config /etc/litestream.yml /data/landing/.state.sqlite

# Landing zone files
source /opt/padelnomics/.env && bash infra/restore_landing.sh

Environment variables

Variable	Default	Description
LANDING_DIR	data/landing	Landing zone root (extraction writes here)
DUCKDB_PATH	local.duckdb	SQLMesh pipeline DB (exclusive write)
SERVING_DUCKDB_PATH	analytics.duckdb	Read-only DB for web app

Coding philosophy

• Simple and procedural — functions over classes, no "Manager" patterns
• Idempotent operations — running twice produces the same result
• Explicit assertions — assert preconditions at function boundaries
• Bounded operations — set timeouts, page limits, buffer sizes

Read coding_philosophy.md (if present) for the full guide.