The snapcraft.yaml schema

doc
1

The snapcraft.yaml file is the main entry point to create a snap through Snapcraft. It contains all the details the snapcraft command needs to build a snap.

:information_source: See Snapcraft checklist for an overview of the typical project details needed before creating snapcraft.yaml.

In general, snapcraft.yaml can be organised into three main sections:

1. top-level metadata, containing values, such as name, typically used by the store:

name: hello
base: core22
version: '2.10'
summary: GNU Hello, the "hello world" snap
description: |
  GNU hello prints a friendly greeting.
grade: stable
confinement: strict

2. apps detailing how apps and services are exposed to the host system:

apps:
  hello:
    command: bin/hello

3. and parts to describes how to import, and potentially build, each required part of the snap:

parts:
  gnu-hello:
    source: http://ftp.gnu.org/gnu/hello/hello-2.10.tar.gz
    plugin: autotools

For further details on the metadata contained within each of the above sections, see one of the following:

  1. Snapcraft top-level metadata
  2. Snapcraft app and service metadata
  3. Snapcraft parts metadata

A set of environment variables is also available during the build process. See Environment variables that Snapcraft exposes for further details.

Additionally, see Snapcraft.yaml reference for a complete overview of the metadata supported by snapcraft.yaml, and Snapcraft advanced grammar to learn how to check for specific conditions for certain YAML keys.

3 Likes
2

Note that you can, as the last resort, check out the schema in the source tree: snapcraft/snapcraft.json at master · snapcore/snapcraft.

1 Like
3

That schema is not relevant for Snapcraft 7.

4

This should have a title change to state snapcraft.yaml format rather than simply snapcraft format. Even better might be to replace format with syntax or schema in addition to adding .yaml. Snapcraft itself is a tool, which does not have a “format”. The configuration file that it consumes, snapcraft.yaml is the thing that has a format!

I haven’t done this myself, as I am wary that changing the title might change the URL and therefore the links from the contents/navigation post, which is rightly locked from my access, so I might break the docs site by doing the change myself without the consequent change to the contents doc.

5

Thanks so much for this suggestion, and I think you’re absolutely right. I’ll do a quick audit of what it might involve across the docs/links, but I think we should change this page to The snapcraft.yaml schema. I’ll do the same for The snap format.

1 Like
6

I don’t think SC7 uses that JSON file anymore for schema; AIUI, the new definition for snapcraft.yaml grammar is here, https://github.com/snapcore/snapcraft/blob/main/snapcraft/projects.py. But I’m not absolutely sure.

7

Snapcraft is still using (and updating) that schema. It’s particularly useful to validate your yaml files before you save them via an editor like VSCode.

8

The last sentence is not accurate – that JSON file no longer defines the current schema for Snapcraft, it’s defined by a number of Python files.

9

Thanks. I’ve removed this reference for now.