⚡ Zetten

The High-Performance Task Runner for Python Backends. Parallel. Deterministic. Fast.

Zetten is a dependency-aware execution engine designed to unify how you run tests, linters, and builds. It ensures that your workflow remains identical across local development environments and any CI platform, only faster.

🚀 The Zetten Philosophy

Modern Python projects often require coordinating various tools (tests, type-checkers, formatters). Zetten eliminates "Glue Code Fatigue" by providing:

• Parallel Execution: Automatically identifies independent tasks and runs them concurrently across your CPU cores.
• Three-Tier Variable: System: Advanced command templating with a strict priority hierarchy: CLI Flags (-k) > Config Vars > Environment Variables.
• Smart Caching: Uses content-addressable hashing to skip tasks if their specific inputs haven't changed since the last run.
• Platform Agnostic: Behaves identically on macOS, Windows, Linux, or any CI/CD provider.
• Dependency Awareness: Define a Directed Acyclic Graph (DAG) of tasks to ensure correct execution order (e.g., setup always precedes test).

✨ Features

• ⚡ Worker Pool Concurrency: Maximizes resource usage by running non-dependent tasks in parallel.
• 🏷️ CI Tagging: Execute logical groups of tasks (e.g., run --tag ci) with a single command.
• 🛡️ Failure Propagation: If a foundational task fails, Zetten halts downstream execution to prevent cascading errors.
• 🔍 Intelligent Diagnostics: Includes zetten doctor to identify environment inconsistencies instantly.
• ⏱️ Performance Analytics: (Coming Soon) Real-time insights into time saved via parallelism.

🛠️ Quick Start

Install Zetten:

pip install zetten

Initiate a project:

zetten init

Define tasks in pyproject.toml:

[tool.zetten.tasks.lint]
cmd = "ruff check src"
inputs = ["src/"]
tags = ["ci"]

[tool.zetten.tasks.test]
cmd = "pytest"
depends_on = ["lint"]
inputs = ["src/", "tests/"]
tags = ["ci"]

[tool.zetten.tasks.build]
description = "Build the project"
# Supports Fallback Syntax: ${VAR:-default}
cmd = "mkdir -p ${build_dir} && python -m build --outdir ${DEST:-dist}"
depends_on = ["lint"]
inputs = ["src/"]

Define tasks in zetten.toml:

[tasks.setup]
cmd = "pip install -r requirements.txt"

[tasks.lint]
cmd = "ruff check src"
inputs = ["src/"]
tags = ["ci"]

[tasks.test]
cmd = "pytest"
depends_on = ["setup"]
inputs = ["src/", "tests/"]
tags = ["ci"]

Run tasks:

zetten run test
zetten run lint test

Zetten will only re-run tasks when their inputs change.

⚙️ The Variable Hierarchy

Zetten uses a deterministic three-tier system to resolve variables:

• Tier 1 (CLI): zetten run build -k build_dir=output (Highest Priority)
• Tier 2 (Config): Values defined in tool.zetten.vars
• Tier 3 (Env): System environment variables (e.g., $USER, $PATH)

🚀 Running in CI

Zetten is designed for the modern CI/CD pipeline. By using Tags and Strict Mode, you can ensure your pipeline is both flexible and safe.

# Force a specific version and environment in CI
zetten run --tag ci -k VERSION=${GITHUB_SHA} -k ENV=prod

If a foundational task fails, Zetten halts downstream execution immediately to save CI minutes and prevent cascading failures.

⚙️ Configuration Model

Configuration is explicit by design:

• No templating
• No conditionals
• No implicit behavior

Configuration lives in:

• pyproject.toml (preferred)
• zetten.toml (for legacy or minimal projects)

If no configuration is found, Zetten will explain how to resolve the issue.

🛠 Commands

• zetten run — Execute tasks with parallel dependency resolution.
• zetten run -k KEY=VAL — Override any variable via the CLI.
• zetten watch — Precision re-runs on input changes.
• zetten graph — Visualizes the Directed Acyclic Graph (DAG) of your tasks.
• zetten doctor — Diagnoses configuration and environmental health issues.
• zetten init — Interactive project setup and template generation.

🛡 Status

Zetten is currently in v0.1. If no configuration file is found, Zetten will provide clear instructions on how to initialize your project.

Documentation

Full documentation is available at: Github Wiki

🤝 Contributing

We love Rust and Python! If you want to help make Zetten even faster:

• Fork the repo.
• Add your feature (don't forget the tests!).
• Open a Pull Request.

Built with ❤️ for the Python community using the speed of Rust.

Please open an issue or discussion on GitHub before proposing large changes.