minimal.toml

The minimal.toml file defines the configuration for Minimal in a codebase.

This file must be present at the base of the repository (i.e. ./minimal.toml), or in a .minimal directory at the base of the repository.

Unless -C is specified, the Minimal CLI searches the directory tree backwards from the current directory till a minimal.toml file is found. This behavior allows minimal to be invoked in project directories.

Example

[upstream]
repo = "https://github.com/gominimal/pkgs"
branch = "main"
locked_commit = "d39aaaa581f983d6b3ba5eaaf383485a602f37f0"

[harness]
use = "pnpm"
build_packages = ["railway"]

[defaults]
state_key = "dev"

[tasks.dev]
exec = "pnpm run dev"

[tasks.preview]
env_vars.PORT = "8080"
bash = "pnpm run build && pnpm run start"

[tasks.deploy]
packages = ["railway"]
exec = "railway up"

[tasks.shell]
interactive = true
packages = ["base", "git", "nano"]
exec = "bash -l"

Schema

[upstream] - Where software comes from

The [upstream] section defines the precise source of packages, harnesses, and profiles. This represents the preceding link in the software supply chain.

[upstream]
repo = "<git URL>"
branch = "<branch>"
locked_commit = "<commit hash>"

locked_commit is automatically updated when minimal update is run.

[[upstream.sideload]] - Additional software sideloaded into your supply chain

Sideload entries let you load in additional packages, harnesses, and profiles from a separate repository, but those packages are built using the version of packages from your upstream.

Each sideload entry is loaded in order from the specified repository, and follows the same schema as [upstream]:

[[upstream.sideload]]
repo = "<git URL>"
branch = "<branch>"
locked_commit = "<commit hash>" # Updated via `minimal update`

Sideload repositories have the same layout as an upstream: that is having a minimal.toml file, and packages/ / harnesses/ / profiles/ directories as needed.

[harness] - How to build code in your repo

[harness]
use = "<harness name>"
build_packages = ["<additional build package>"]     # optional
runtime_packages = ["<additional runtime package>"] # optional

The [harness] section configures the harness to use for building code, if any.

The environment variables and packages configured on a harness are inherited on all tasks in this repository.

build_packages and runtime_packages are optional fields that allow you to declare additional package dependencies for build time or run time respectively.

[defaults] - Settings for all tasks

[defaults]
profile = "<profile name>" # optional
state_key = "<state key>"  # optional

When set, defaults.profile will set a profile on all tasks which do not set a profile.

When set, defaults.state_key will set a state key on all tasks which do not set state_key.

[tasks.*] - Run tasks, scripts, & dev tooling

See: tasks.

[outputs.*] - Artifacts produced by minimal materialize

Each [outputs.<name>] section defines an artifact that can be produced with minimal materialize <name> -o <path>.

[outputs.<name>]
type = "<output type>"          # required; alias: `ty`
packages = ["<package>", ...]   # optional; defaults to ["base"] when empty
arch = "<arch>"                 # optional; e.g. "amd64", "arm64"
path = "<path>"                 # raw-file only; required there, invalid for oci-image
entrypoint = "<cmd>"            # oci-image only; string or list of strings
cmd = ["<arg>", ...]            # oci-image only; string or list of strings
vars = { KEY = "value" }        # oci-image only; alias: `env_vars`

Output types

Fields

• type (alias: ty) — The output kind, either oci-image or raw-file. Defaults to oci-image when omitted.
• packages — Packages to include in the materialized output. When omitted or empty, defaults to ["base"].
• arch — Target architecture for OCI images. Common values: amd64, arm64. The CLI flag --arch overrides this; if neither is set, the host architecture is used.
• path — (raw-file only) Path, relative to the package file tree, of the single file to extract. Required for raw-file outputs; supplying it on an oci-image output is an error.
• entrypoint — (oci-image only) OCI image entrypoint. May be a string ("/app/server") or a list (["/bin/sh", "-c"]).
• cmd — (oci-image only) OCI image default command. Same string-or-list shape as entrypoint.
• vars (alias: env_vars) — (oci-image only) Environment variables baked into the image as a KEY = "value" table.

Setting an oci-image-only field (entrypoint, cmd, vars) on a raw-file output — or setting path on an oci-image output — is rejected when the minimal.toml is parsed.

Examples

A minimal OCI image of just the base packages, useful for ad-hoc shells:

[outputs.base-image]
type = "oci-image"

minimal materialize base-image -o ./base.tar

A server image with extra packages, an entrypoint, and an env var:

[outputs.app]
type = "oci-image"
arch = "arm64"
packages = ["base", "openssl"]
entrypoint = "/app/server"
vars = { PORT = "8080" }

minimal materialize app -o ./app.tar

Override the architecture at the command line:

minimal materialize app --arch amd64 -o ./app-amd64.tar

A raw-file output extracts a single file from a package. Here the kernel Image is pulled out of the virtio-kernel-raw package:

[outputs.virtio-kernel]
type = "raw-file"
packages = ["virtio-kernel-raw"]
path = "usr/share/virtio-linux/Image"

minimal materialize virtio-kernel -o ./Image