pacta 0.0.1

A Python tool for enforcing and visualizing software architecture.

Architecture Testing & Architecture-as-Code

PyPI • Docs • Issues

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Warning: Experimental. Expect breaking changes.

Pacta enforces architectural rules in your codebase. Define layers, set boundaries, catch violations in CI.

Supported languages:

• Python
• Java (coming soon)
• Go (coming soon)
• C# (coming soon)

pip install pacta
pacta scan . --model architecture.yml --rules rules.pacta.yml

Why?

Codebases rot. The "clean architecture" you designed becomes spaghetti after a few quarters. Pacta catches violations early — in PRs, not post-mortems.

What it does

• Static analysis — parses Python AST, builds import graph
• Layer enforcement — domain can't import from infra, etc.
• Baseline mode — fail only on new violations, not legacy debt
• Snapshots — version your architecture like code

Quick example

Define your layers in architecture.yml:

version: 1
system:
  id: myapp
  name: My App

containers:
  backend:
    code:
      roots: [src]
      layers:
        domain:
          patterns: [src/domain/**]
        infra:
          patterns: [src/infra/**]

Add rules in rules.pacta.yml:

rule:
  id: no_domain_to_infra
  name: Domain cannot depend on Infrastructure
  severity: error
  target: dependency
  when:
    all:
      - from.layer == domain
      - to.layer == infra
  action: forbid
  message: Domain layer must not import from Infrastructure

Run it:

$ pacta scan . --model architecture.yml --rules rules.pacta.yml

✗ 2 violations (2 error) [2 new]
  ✗ ERROR [no_domain_to_infra] Domain cannot depend on Infrastructure @ src/domain/user.py:3:1
    status: new
    Domain layer must not import from Infrastructure

Baseline workflow

Got legacy violations? Save a baseline and only fail on new ones:

# Save current state
pacta scan . --model architecture.yml --rules rules.pacta.yml --save-ref baseline

# Later, in CI — fail only on new violations
pacta scan . --model architecture.yml --rules rules.pacta.yml --baseline baseline

Docs

• CLI Reference
• Architecture Model
• Rules DSL

License

AGPL-3.0-only. See LICENSE.