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Quick Start

This guide walks you through setting up datamitsu in a project, downloading tools, and running them.

1. Create a Configuration File​

datamitsu looks for a configuration file at your git root. Create one of:

  • datamitsu.config.ts (TypeScript — recommended)
  • datamitsu.config.js (JavaScript)
  • datamitsu.config.mjs (ES modules)

Here's a minimal example that adds hadolint (a Dockerfile linter):

/// <reference path=".datamitsu/datamitsu.config.d.ts" />

// datamitsu.config.ts
function getConfig(prev) {
  return {
    ...prev,
    apps: {
      ...prev.apps,
      hadolint: {
        binary: {
          binaries: {
            linux: {
              amd64: {
                url: "https://github.com/hadolint/hadolint/releases/download/v2.12.0/hadolint-Linux-x86_64",
                hash: "56de6d5e5ec427e17b74fa48d51271c7fc0d61571c37f4a4c87c04f911dc5f94",
                contentType: "binary",
              },
            },
            darwin: {
              amd64: {
                url: "https://github.com/hadolint/hadolint/releases/download/v2.12.0/hadolint-Darwin-x86_64",
                hash: "911006e5fe41981c319cf4ef331d12bd1c02b594e4a1e9a4b1dbe5fbab0e5b5c",
                contentType: "binary",
              },
              // arm64: no native ARM64 binary; omit or use x86_64 via Rosetta 2
            },
          },
        },
      },
    },
    tools: {
      ...prev.tools,
      hadolint: {
        name: "Hadolint",
        operations: {
          lint: {
            app: "hadolint",
            args: ["{file}"],
            scope: "per-file",
            globs: ["**/Dockerfile", "**/Dockerfile.*"],
          },
        },
      },
    },
  };
}

globalThis.getConfig = getConfig;
globalThis.getMinVersion = () => "0.0.1";

Each binary entry requires a url and a hash (SHA-256). datamitsu refuses to download any binary without a hash.

2. Initialize the Project​

Run init from your git root to download all configured tools:

datamitsu init

This downloads and verifies binaries, installs runtime-managed apps, and creates any managed config symlinks in .datamitsu/.

Use --all to also download optional tools:

datamitsu init --all

3. Execute a Tool​

Run any managed tool directly:

datamitsu exec hadolint -- Dockerfile

The -- separates datamitsu arguments from the tool's arguments.

4. Run Checks​

Run all configured lint and fix operations:

# Run fix then lint in sequence
datamitsu check

# Run only linting
datamitsu lint

# Run only auto-fixes
datamitsu fix

5. Set Up Project Configs​

Generate configuration files (like .gitignore entries, lefthook configs, etc.) for your project type:

datamitsu setup

This detects your project type and generates appropriate configuration files.

Opt-in to tools one at a time​

In a project with many configured tools, the default experience is "everything runs at once". Pass --opt-in-tools to start with all tools disabled and turn them on deliberately:

datamitsu setup --opt-in-tools

This runs the normal setup and then writes a .datamitsuignore at your git root that disables every configured tool via a single catch-all rule:

# Generated by `datamitsu setup --opt-in-tools`.
# All configured tools are disabled by default (opt-in model).
# Enable a tool by removing it from the list below (or add "!**/*: <tool>").
**/*: eslint, golangci-lint, hadolint, prettier, shellcheck

Enable a tool by removing its name from the list (for example, delete prettier to let prettier run). Setup refuses to overwrite an existing .datamitsuignore, so your manual selections are never lost — use --dry-run to preview without writing. See Generating an all-disabled file.

Configuration Layers​

datamitsu loads config in layers, each extending the previous:

Every config must export getMinVersion() (returns the minimum datamitsu version required) and getConfig(prev) (receives the previous layer's config and returns a new config that extends or overrides it).

Next Steps​