Technical Team/Use Cases/2.0/Build System Yocto

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Title:  Yocto Build System


Note: This is not a detailed background. You are encouraged  to read up on the Yocto Project by using the following link:  <a href=""></a>

The Yocto Project provides a build system which can be used to provide, as an example, a file system/kernel/boot loader image that can be downloaded onto a device and executed. When Yocto builds a package the package source can come from various sources such as source code control system like GIT, a tarball, patches and so forth. Entities providng a Yocto build for their hardware may also be providing pacthes for the package.Whenever a build is executed, it is possible that the files in a package are updated (added, modified, removed, etc).

Yocto uses recipes to build packages. These recipes do contain a License field. The current short names do not match SPDX short names and likely will not. It was rather difficult to get alignment on the current ones used. There is talk on the Yocto project about converting the Yocto short names into SPDX ones. 

Primary Actors:

Yocto User: Receives a Yocto build for a device. Executes the build.

Package Maintainer: These are upstream projects that a Yocto based build consumes. This upstream project could be a company that provides a package as well. A Package Maintainer could be viewed as having a secondary interest in this use case as their package may be consumed by a Yocto build even though they as packages maintainers have no vested interest in Yocto.

the Yocto Project: Provides the Yocto build system.

Build System Provider: They provide a  Yocto based build, for example for their product. They may also provide patches to Packages that the recipes pull or may even add their own packages.

Goal in Context:  To execute a Yocto based build and generate an image for a hardware device or simulator  and to have SPDX documents that describe the licensing for all copyrightable artifacts pulled in by the build system and used to generate that image (i.e. not just artifacts that make it into the image, everything and everything that it pulls including the build system).  Note: envision we could be talking about 1000's of related SPDX documents

Stakeholders and Interests: 

Yocto User:

       A. To receive accurate and clear information of licensing for all copyrightable

            elements used in the build and for the build system.

       B. To be able to comply easily with licenses for all copyrightable elements used in

            the build and the build system.

2. Package Maintainer:

       A. To communicate the license information for their package.

       B. To have their licenses respected.


3. the Yocto Project:

       A. To communicate the license information for their build system and the licensing of each package

           (currently via the license field in a recipe).

       B. To have their licenses respected.


4. Build System Provider:

      A. To communicate the licensing information for the build they are providing.

      B. To comply with all the licenses used in the build the system they are providing.



  1. A yocoto build is created.
  2. Packages used in the Yocoto build have SPDX documents describing the copyrigthable elements of the package.
  3. A patch for a package used in the build is created.


Main Success Scenario: A user executing a Yocto based build gets SPDX documents that describe the licensing for all copyrightable elements that were used to create the build and are the result of a build.

Failed End Condition: Inaccurate or incomplete licensing information is provided for all packages used in the build and/or for the Yocto build system.


A Yocto user executes a build.


Note: I forgot a point around RPMs when doing this and need to follow up again with the Yocto Project.