6. Install a Python Package in Yocto

Your project is going well, and your application is working beautifully, but now you want to add a new, wonderful package to your project.

While installing packages using pip install is simple on your computer, you need to follow a different approach in Yocto if you want to customize your own image while keeping it small.

Before proceeding, make sure you understand the tutorial First Steps with Yocto.

6.1. Check if the recipe is already available

You can check if a recipe is already available by going inside the sources folder and doing:

find -name "my-lib"

NOTE You can also check the OpenEmbedded Website for available recipes.

6.2. Add a recipe

If Yocto provides a recipe for your package, the integration process is straightforward. Here’s how:

  1. Open your conf/local.conf file

  2. Add the following line to include the package in your image:

IMAGE_INSTALL += " python3-my-lib"

  1. Replace my-lib with the actual name of your package

  2. Build your Yocto image to incorporate the package with: bitbake my-image

6.3. Create your recipe with PyPI

If you don’t have an existing recipe and the package is available on PyPi, you have the power to create your own.

6.3.1. Prerequisites

Make sure you have your own layer installed and configured before creating your recipe. If it’s not the case, check the tutorial Creating Your Own Layer with Yocto.

6.3.2. Creating the recipe

  1. Find the package version you need on the PyPI website

  2. Choose a version for you package and name your recipe following this format: mylib_1.2.3.bb, replacing ‘mylib’ with the package name and ‘1.2.3’ with the desired version

  3. Create a new recipe with the following content:

SUMMARY = "MyLib Python package"
HOMEPAGE = "https://example.com/mylib"
LICENSE = "MIT"
LIC_FILES_CHKSUM = "file://${COMMON_LICENSE_DIR}/MIT;md5=0835ade698e0bcf8506ecda2f7b4f302"

SRC_URI[md5sum] = "1234567890abcdef1234567890abcdef"
# or
# SRC_URI[sha256sum] = "abcdef1234567890abcdef1234567890abcdef1234567890abcdef1234567890"

inherit pypi setuptools3

  1. Replace the LICENSE, LIC_FILES_CHKSUM and SRC_URI values with the actual checksums you obtained from the PyPI website

  2. Check the dependencies needed for your library and add them to your Yocto setup

  3. Try building the recipe using the bitbake command: bitbake mylib

If everything is working fine, that’s great! You have successfully created a recipe for your package.

6.3.3. Troubleshooting

Running into issues? Don’t worry, it happens to the best of us. Here are some tips:

  1. Ensure that all dependencies are correctly specified in the recipe and check the recipe of those dependencies

  2. Create a patch to fix the broken code

To learn more on recipes, check the openembedded meta-python layer.

6.4. Conclusion

Yocto offers multiple ways to add Python packages, whether through existing recipes or custom recipes.

Remember to refer to the official Yocto documentation and the PyPI website for valuable insights: