pykorm 0.45

Pykorm: a dead simple Kubernetes ORM

pykorm - Python Kubernetes Object-relational mapping (ORM)

pykorm is a simple library that links your models to their kubernetes counterpart.

Each model and instance on your code is thus directly linked to your kubernetes cluster and modifications are thus reflected both ways.

Examples

Namespaced Custom Resource

Kubernetes example

apiVersion: apiextensions.k8s.io/v1
kind: CustomResourceDefinition
metadata:
  name: peaches.pykorm.infomaniak.com
spec:
  group: pykorm.infomaniak.com
  names:
    kind: Peach
    listKind: PeachList
    plural: peaches
    singular: peach
  scope: Namespaced
  versions:
  - name: v1
    served: true
    storage: true
    schema:
      openAPIV3Schema:
        type: object
        properties:
          spec:
            type: object
            properties:
              variety:
                type: string
            required:
              - variety


    additionalPrinterColumns:
    - name: Variety
      type: string
      description: The variety of the peach
      jsonPath: .spec.variety

Class definition

In order to link a python class to a kubernetes CustomResourceDefinition, you need to inherit the class from pykorm's one and annotate it with the kubernetes CRD information:

import pykorm

@pykorm.k8s_custom_object('pykorm.infomaniak.com', 'v1', 'peaches')
class Peach(pykorm.NamespacedModel):
    variety: str = pykorm.fields.Spec('variety')

    def __init__(self, namespace: str, name:str, variety:str):
        self.namespace = namespace
        self.name = name
        self.variety = variety

Create a CR

In order to create a kubernetes custom resource from python, you just have to instantiate the class and save it with pykorm:

import pykorm
pk = pykorm.Pykorm()

cake_peach = Peach(namespace='default', name='cake-peach', variety='Frost')
pk.save(cake_peach)

as you can see, the model is instantly ensured in kubernetes:

$ kubectl get peach -n default
NAME         VARIETY
cake-peach   Frost

List resources

Pykorm can also list resources from kubernetes

>>> all_peaches = Peach.query.all()
>>> for peach in all_peaches:
>>>  print(peach)
<Peach namespace=default, name=cake-peach, variety=Frost>

Delete resources

You can delete a resource with pykorm too:

pk.delete(peach)

$ kubectl get peach
No resources found in default namespace.

More examples

For more examples, don't hesitate to look into the examples/ directory

Where is pykorm

pykorm is still very young and very naive missing quite a lot of features (filtering, relationships, etc.). It was originally created because a lot of boilerplate code was written each time a custom object had to be interfaced with kubernetes.

Work on pykorm is actually on the way. Don't hesitate to contribute to the project if you have the energy for it !

Limitations

As of now, pykorm only supports CustomResourceDefinitions (as accessed by the kubernetes.client.CustomObjectsApi API) and doesn't yet work with "native" resources like Node, Deployment, Service, etc.

Equivalences

Python	Kubernetes
Class	CustomResourceDefinition
Instance	CustomResource