nalbury / cdk8s-utils

Python cdk8s helpers

Cdk8s Utils

This project contains helper utilities for using cdk8s in python.

Usage

The utilities here build on top of the standard cdk8s workflow, but instead of using the npm installed cdk8s cli, everything is done with python tooling and a typed Config data class.

Example

from dataclasses import dataclass

from cdk8s import Chart, ApiObject, ApiObjectMetadata

from constructs import Construct

from cdk8s_utils import cli


@dataclass
## defaults can be overriden at runtime by providing a config.yaml file with the --config flag
# for example:
# --- !Config
# image: "nginx:notlatest"
#
class Config:
    image: str = "nginx:latest"

# our actual cdk8s Chart subclass, all Config class attribuates are available for templating the manifests as needed
class ExampleChart(Chart):
    def __init__(
        self,
        scope: Construct,
        id: str,
        config: Config,
    ):
        labels = {"app": id}
        super().__init__(scope, id, disable_resource_name_hashes=True, labels=labels)
        ApiObject(
            self,
            id="test-resource",
            api_version="v1alpha1",
            kind="TestResource",
            metadata=ApiObjectMetadata(name="test", labels={"image": config.image}),
        )
        self.config = config

# main script simply executes the cli.run() function to synthesize our manifests to both stdout and the default `dist/` path
# a --help flag is available for more info on cli usage options
if __name__ == "__main__":
    cli.run(Config, ExampleChart, cli_args=None)

It can be run as a standard python executable e.g. python main.py --help

usage: cdk8s-app [-h] [--config CONFIG] [--print | --no-print] name

positional arguments:
  name                 resource name

options:
  -h, --help           show this help message and exit
  --config CONFIG      path to config file with input values (default:
                       None)
  --print, --no-print  if true, the manifests will be printed to
                       stdout (default: True)

Cookiecutter template

A complete cdk8s python framework can be generated for a new python project with the cookiecutter template here.

Building and Pushing

The package is hosted on pypi for installation via pip etc. As a result a valid API token for a registered pypi.org user is required for pushing.

NOTE: use the provided devcontainer for this.

The package can be built and pushed using:

make push 

This will:

• create a venv in .venv
• run pip-compile (from pip-tools) to generate a complete pinned set of requirements.txt files from the pyproject.toml
• build the python package artifacts
• prompt for user/token for pypi.org
• push the package artifacts to pypi.org

TODO: some CI here