sparkrules 1.0.0

Drools-equivalent business rule engine reference implementation

sparkrules

A Drools-style business rule engine for Python. Define rules in DRL, evaluate facts, get explainable results — no JVM required.

from sparkrules.executor import RuleExecutor

result = RuleExecutor().run(
    {"amount": 1500, "region": "US"},
    'rule "high-value" when $f : Fact( amount > 1000 ) then result.risk = "high"; end',
)
print(result.fired)          # True
print(result.action_output)  # {'risk': 'high'}

Install

pip install sparkrules

Why SparkRules?

• No JVM, no Drools server — pure Python rule engine with DRL syntax, decision tables, and explainable outputs
• Production-ready API — FastAPI service with a browser-based Rules Workbench (Monaco editor, LSP diagnostics, simulations)
• Optional Spark integration — scale to cluster DataFrames with apply_drl() when you need it, stay on pure Python when you don't
• Governance built in — versioned rules, namespace scoping, dev→stage→prod promotion, deprecation workflows
• 100% test coverage — 521 tests, property-based testing with Hypothesis, enforced coverage gate

Performance

The default API path runs pure Python (no Spark). Typical throughput on a single core:

Scenario	Throughput
Simple single-pattern rule	~5,000-10,000 evals/sec
Multi-condition rules with actions	~1,000-5,000 evals/sec
Full API round-trip (HTTP + parse + eval)	~200-500 req/sec

For higher throughput, use apply_drl() with PySpark to distribute evaluation across a cluster. See docs/BENCHMARKS.md for methodology and docs/KNOWN_LIMITATIONS.md for honest scope boundaries.

Quick start (from source)

git clone https://github.com/vaquarkhan/sparkrules.git
cd sparkrules
python -m pip install -e ".[test]"
python -c "import sparkrules; print('ok', sparkrules.__version__)"
pytest tests/ -q

Start the API + Workbench

pip install sparkrules
python -m uvicorn sparkrules.api.app:create_app --factory --host 127.0.0.1 --port 8042

Then open:

• OpenAPI docs: http://127.0.0.1:8042/docs
• Rules Workbench: http://127.0.0.1:8042/workbench/

Or use Docker:

docker compose up --build
# → http://127.0.0.1:8042/workbench/

Feature highlights

Rule authoring

• DRL-style when / then rule language with salience, agenda groups, activation groups
• Decision tables with hit policies: UNIQUE, FIRST, PRIORITY, COLLECT
• XLSX decision-table import/export
• Rule templates with placeholder substitution

Execution

• Explainable outputs: bound fields, action outputs, reason codes
• Batch, two-pass, and streaming evaluation modes
• Deterministic replay with versioned rule snapshots
• Multi-pattern rules with local Cartesian expansion

API and Workbench

• FastAPI with OpenAPI docs, health endpoint, rule CRUD, simulations
• Rules Workbench — browser UI with Monaco DRL editor, validate + LSP diagnostics, simulation, deployment readout
• Shadow, coverage, counterfactual, and chain simulation modes
• Time-travel debug capture and replay
• Data quality checks (not-null, range, in-set)

Governance

• Versioned metadata store (in-memory, DuckDB, Iceberg, Postgres backends)
• Rule namespaces for multi-project scoping
• Dev → stage → prod promotion pins
• Deprecation workflow: propose, approve, enforce

Spark integration (optional)

• apply_drl(df, drl) for cluster DataFrame evaluation via mapPartitions
• Pure Python by default — Spark is opt-in, not required
• Platform config: local, AWS Glue, Databricks, GCP Dataproc, Azure Synapse

Spark vs Python: the API and Workbench run pure Python. For cluster-scale evaluation, see docs/SPARK_INTEGRATION.md.

How it works

1. Author rules in DRL or decision-table form
2. Parse and validate rule syntax
3. Evaluate facts and produce explainable results
4. Version, replay, and govern rule lifecycle

Architecture details: docs/HOW_IT_WORKS.md

Use cases

• POS end-of-day decisioning
• Streaming authorization logic
• Settlement replay and correction
• Underwriting decision support
• Clinical trial eligibility screening

Details: docs/USE_CASES.md · Examples: examples/

API key (optional)

Set SPARKRULES_API_KEY to require authentication on mutating endpoints and sensitive GETs. Public without key: /health, OpenAPI, Workbench static shell. See API run details.

Documentation

Topic	Link
Features	docs/FEATURES.md
Architecture	docs/HOW_IT_WORKS.md
Developer guide	docs/DEVELOPER_GUIDE.md
Use cases	docs/USE_CASES.md
Spark integration	docs/SPARK_INTEGRATION.md
Governance	docs/GOVERNANCE.md
Benchmarks	docs/BENCHMARKS.md
Known limitations	docs/KNOWN_LIMITATIONS.md
Roadmap	docs/ROADMAP.md
Publishing / CI	docs/PUBLISHING.md
Contributing	CONTRIBUTING.md
Changelog	CHANGELOG.md

License

Licensed under the Apache License, Version 2.0.

Copyright 2026 Vaquar Khan. See CITATION.cff for citation details.