Multi platform configLearn how to set up for different platforms/OS's

Pixi's vision includes being supported on all major platforms. Sometimes that needs some extra configuration to work well. On this page, you will learn what you can configure to align better with the platform you are making your application for.

Here is an example pixi.toml that highlights some of the features:

[project]
# Default project info....
# A list of platforms you are supporting with your package.
platforms = ["win-64", "linux-64", "osx-64", "osx-arm64"]
 
[dependencies]
python = ">=3.8"
 
[target.win-64.dependencies]
# Overwrite the needed python version only on win-64
python = "3.7"
 
 
[activation]
scripts = ["setup.sh"]
 
[target.win-64.activation]
# Overwrite activation scripts only for windows
scripts = ["setup.ps1"]

Platform definition

The project.platforms defines which platforms your project supports. When multiple platforms are defined, pixi determines which dependencies to install for each platform individually. All of this is stored in a lockfile.

Running pixi install on a platform that is not configured will warn the user that it is not setup for that platform:

❯ pixi install
  × the project is not configured for your current platform
   ╭─[pixi.toml:6:1]
 6 │ channels = ["conda-forge"]
 7 │ platforms = ["osx-64", "osx-arm64", "win-64"]
   ·             ────────────────┬────────────────
   ·                             ╰── add 'linux-64' here
 8 │
   ╰────
  help: The project needs to be configured to support your platform (linux-64).

Target specifier

With the target specifier, you can overwrite the original configuration specifically for a single platform. If you are targeting a specific platform in your target specifier that was not specified in your project.platforms then pixi will throw an error.

Dependencies

It might happen that you want to install a certain dependency only on a specific platform, or you might want to use a different version on different platforms.

[dependencies]
python = ">=3.8"
 
[target.win-64.dependencies]
msmpi = "*"
python = "3.8"

In the above example, we specify that we depend on msmpi only on Windows. We also specifically want python on 3.8 when installing on Windows. This will overwrite the dependencies from the generic set of dependencies. This will not touch any of the other platforms.

You can use pixi's cli to add these dependencies to the pixi.toml

pixi add --platform win-64 posix

This also works for the host and build dependencies.

pixi add --host --platform win-64 posix
pixi add --build --platform osx-64 clang

Which results in this.

[target.win-64.host-dependencies]
posix = "1.0.0.*"
 
[target.osx-64.build-dependencies]
clang = "16.0.6.*"

Activation

Pixi's vision is to enable completely cross-platform projects, but you often need to run tools that are not built by your projects. Generated activation scripts are often in this category, default scripts in unix are bash and for windows they are bat or ps1

To deal with this, you can define your activation scripts using the target definition.

[activation]
scripts = ["setup.sh", "local_setup.bash"]
 
[target.win-64.activation]
scripts = ["setup.ps1", "setup.bat", "local_setup.bat"]

When this project is run on win-64 it will only execute the target scripts not the scripts specified in the default activation.scripts