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Project configuration


Versions within atopile follow the semantic versioning 2.x schema. See for details Semantic versions may be prefixed with a "v", so v1.0.0 == 1.0.0

ato.yaml project config

The ato.yaml is significant indicator for a project:

  1. It marks the root of a project. The ato commands in the CLI is largely dependant upon the ato.yaml to know what project you're referring to.
  2. It contains project-level configuration information like where to build from, which layouts have what entry-points
  3. Lists project dependencies and the required versions of those dependencies
  4. Specifies what compiler version the project is intended to build with

build key

This is for build-configuration information.

Each key under build: is a layout name, and the value is a list of entry-points for that layout.


    entry: "elec/src/demo.ato:Demo"  # This is the root of the build

fail_on_drcs is a boolean value, defaulting to false. If set to true, the build will fail if any DRCs errors are found.


Each package listed under the dependencies: key is automatically downloaded and installed for users when they run the ato install command from within a project. These dependencies are anticipated to make the project run.

Each dependency may have constraints on its version using the following operators:

Assuming dependency says my-package <operator>1.2.3 the following table describes whether each of the operators would match.

They're in approximate order of usefulness/recommendation

Op 0.1.1 1.1.0 1.2.3 1.2.4 1.3.0 1.4.0 2.0.0 Description
^ >=, up to the next major
~ >=, up to the next minor
== Exactly
* Any
! Not (usually used in combination with others)

>=, <=, >, < all work, but have niche value. If you need to use them, something's probably broken.

Compiler version

eg. ato-version: v0.1.8

The installed compiler is matched against this value to see if the project is buildable in the current environment.

It's matched using either: - ~ if the installed compiler version <1.0.0 - else ^ (up to the next major)

Practically, this means breaking compiler changes are indicated using the minor (eg. 0.1.0, 0.2.0, 0.3.0, 0.4.0) until version 1.0.0.

When you upgrade your compiler with breaking changes, you need to update your project to match the language changes, bumping this version in your project's ato.yaml file