Multiple Packages in Workspace

In this tutorial, we will show you how to integrate multiple Pixi packages into a single workspace.

Warning

pixi-build is a preview feature, and will change until it is stabilized. Please keep that in mind when you use it for your projects.

Why is This Useful?

The packages coming from conda channels are already built and ready to use. If you want to depend on a package you therefore typically get that package from such a channel. However, there are situations where you want to depend on the source of a package. This is the case for example if you want to develop on multiple packages within the same repository. Or if you need the changes of an unreleased version of one of your dependencies.

Let's Get Started

In this tutorial we will showcase how to develop two packages in one workspace. For that we will use the rich_example Python package developed in chapter Building a Python package and let it depend on the python_binding C++ package developed in chapter Building a C++ package.

We will start with the original setup of rich_example and copy python_binding into a folder called packages. The source directory structure now looks like this:

.
├── packages
│   └── python_bindings
│       ├── CMakeLists.txt
│       ├── pixi.toml
│       └── src
│           └── bindings.cpp
├── pixi.lock
├── pixi.toml
├── pyproject.toml
└── src
    └── rich_example
        └── __init__.py

Within a Pixi manifest, you can manage a workspace and/or describe a package. In the case of rich_example we choose to do both, so the only thing we have to add is the dependency on the python_bindings.

pixi.toml

[workspace]
channels = [
  "https://prefix.dev/pixi-build-backends",
  "https://prefix.dev/conda-forge",
]
platforms = ["win-64", "linux-64", "osx-arm64", "osx-64"]
preview = ["pixi-build"]

[dependencies]
python_bindings = { path = "packages/python_bindings" }
rich_example = { path = "." }

We only want to use the workspace table of the top-level manifest. Therefore, we can remove the workspace section in the manifest of python_bindings.

packages/python_bindings/pixi.toml

-[workspace]
-channels = [
-  "https://prefix.dev/pixi-build-backends",
-  "https://prefix.dev/conda-forge",
-]
-platforms = ["osx-arm64", "osx-64", "linux-64", "win-64"]
-preview = ["pixi-build"]
-
-[dependencies]
-python_bindings = { path = "." }
-
-[tasks]
-start = "python -c 'import python_bindings as b; print(b.add(1, 2))'"

There is actually one problem with rich_example. The age of every person is off by one year!

┏━━━━━━━━━━━━━━┳━━━━━┳━━━━━━━━━━━━━┓
┃ name         ┃ age ┃ city        ┃
┡━━━━━━━━━━━━━━╇━━━━━╇━━━━━━━━━━━━━┩
│ John Doe     │ 30  │ New York    │
│ Jane Smith   │ 25  │ Los Angeles │
│ Tim de Jager │ 35  │ Utrecht     │
└──────────────┴─────┴─────────────┘

We need to add one year to the age of every person. Luckily python_bindings exposes a function add which allows us to do exactly that.

src/rich_example/__init__.py

from dataclasses import dataclass, fields
from rich.console import Console
from rich.table import Table
import python_bindings


@dataclass
class Person:
    name: str
    age: int
    city: str


def main() -> None:
    console = Console()

    people = [
        Person("John Doe", 30, "New York"),
        Person("Jane Smith", 25, "Los Angeles"),
        Person("Tim de Jager", 35, "Utrecht"),
    ]

    table = Table()

    for column in fields(Person):
        table.add_column(column.name)

    for person in people:
        updated_age = python_bindings.add(person.age, 1)
        table.add_row(person.name, str(updated_age), person.city)

    console.print(table)

If you run pixi run start, the age of each person should now be accurate:

┏━━━━━━━━━━━━━━┳━━━━━┳━━━━━━━━━━━━━┓
┃ name         ┃ age ┃ city        ┃
┡━━━━━━━━━━━━━━╇━━━━━╇━━━━━━━━━━━━━┩
│ John Doe     │ 31  │ New York    │
│ Jane Smith   │ 26  │ Los Angeles │
│ Tim de Jager │ 36  │ Utrecht     │
└──────────────┴─────┴─────────────┘

Conclusion

In this tutorial, we created a Pixi workspace containing two packages. The manifest of rich_example describes the workspace as well as the package, with python_bindings only the package section is used. Feel free to add more packages, written in different languages to this workspace!

Thanks for reading! Happy Coding 🚀

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