mille

Architecture Checker — static analysis CLI for layered architecture rules

mille is a CLI tool that enforces dependency rules for layered architectures (Clean Architecture, Onion Architecture, Hexagonal Architecture, etc.).

It is implemented in Rust, supports multiple languages from a single TOML config, and is designed to run in CI/CD pipelines.

Features

How to Install

cargo (Rust users)

cargo install mille

go install

go install github.com/makinzm/mille/packages/go@latest

The Go wrapper embeds mille.wasm (the compiled Rust core) and runs it via wazero — a zero-dependency WebAssembly runtime. No network access or caching required; the binary is fully self-contained.

Direct binary download

Pre-built binaries for each platform are available on GitHub Releases:

# Example: Linux x86_64
curl -L https://github.com/makinzm/mille/releases/latest/download/mille-<version>-x86_64-unknown-linux-gnu.tar.gz | tar xz
./mille check

Quick Start

1. Create mille.toml

Place mille.toml in your project root:

Rust project example:

[project]
name      = "my-app"
root      = "."
languages = ["rust"]

[[layers]]
name            = "domain"
paths           = ["src/domain/**"]
dependency_mode = "opt-in"
allow           = []
external_mode   = "opt-in"
external_allow  = []

[[layers]]
name            = "usecase"
paths           = ["src/usecase/**"]
dependency_mode = "opt-in"
allow           = ["domain"]
external_mode   = "opt-in"
external_allow  = []

[[layers]]
name            = "infrastructure"
paths           = ["src/infrastructure/**"]
dependency_mode = "opt-out"
deny            = []
external_mode   = "opt-out"
external_deny   = []

[[layers]]
name            = "main"
paths           = ["src/main.rs"]
dependency_mode = "opt-in"
allow           = ["domain", "infrastructure", "usecase"]
external_mode   = "opt-in"
external_allow  = ["clap"]

  [[layers.allow_call_patterns]]
  callee_layer  = "infrastructure"
  allow_methods = ["new", "build", "create", "init", "setup"]

Go project example:

[project]
name      = "my-go-app"
root      = "."
languages = ["go"]

[resolve.go]
module_name = "github.com/myorg/my-go-app"

[[layers]]
name            = "domain"
paths           = ["domain/**"]
dependency_mode = "opt-in"
allow           = []

[[layers]]
name            = "usecase"
paths           = ["usecase/**"]
dependency_mode = "opt-in"
allow           = ["domain"]

[[layers]]
name            = "infrastructure"
paths           = ["infrastructure/**"]
dependency_mode = "opt-out"
deny            = []

[[layers]]
name            = "cmd"
paths           = ["cmd/**"]
dependency_mode = "opt-in"
allow           = ["domain", "usecase", "infrastructure"]

2. Run mille check

mille check

Exit codes:

Configuration Reference

[project]

[[layers]]

[[layers.allow_call_patterns]]

Restricts which methods may be called on a given layer's types. Only valid on the main layer.

[resolve.go]

How it Works

mille uses tree-sitter for AST-based import extraction — no regex heuristics. The core engine is language-agnostic; language-specific logic is isolated to the parser and resolver layers.

mille.toml
    │
    ▼
Layer definitions
    │
Source files (*.rs, *.go, ...)
    │ tree-sitter parse
    ▼
RawImport list
    │ Resolver (stdlib / internal / external)
    ▼
ResolvedImport list
    │ ViolationDetector
    ▼
Violations → terminal output

Dogfooding

mille checks its own source code on every CI run:

mille check   # uses ./mille.toml

See mille.toml for the architecture rules applied to mille itself.

Documentation

• spec.md — Full specification (in Japanese)
• docs/TODO.md — Development roadmap