Pykorm: a dead simple Kubernetes ORM
Project description
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
Setup
First of all, you need to have Custom Resource Definitions on your cluster.
This README will use the following Namespaced resource. You can apply it on your
cluster with kubectl
.
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 NamespacedModel
or ClusterModel
and annotate it with the kubernetes CRD information like so:
import pykorm
@pykorm.k8s_custom_object('pykorm.infomaniak.com', 'v1', 'peaches')
class Peach(pykorm.NamespacedModel):
variety: str = pykorm.fields.Spec('variety')
Notice that a class inheriting from pykorm.NamespacedModel
already has the
name
and namespace
fields setup.
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.save()
:
import pykorm
pk = pykorm.Pykorm()
cake_peach = Peach(namespace='default', name='cake-peach', variety='Frost')
pk.save(cake_peach) # We save the resource
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>
# Filter by namespace
>>> Peach.query.filter_by(namespace='default').filter_by(variety='Frost').all()
You can even filter resources by some criterion:
>>> Peach.query.filter_by(name='cake-peach').all()
[<Peach namespace=default, name=cake-peach, variety=Frost>]
>>> Peach.query.filter_by(namespace='kube-system').all()
[]
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
Is pykorm stable ?
pykorm is still very young and very naive. It's also missing quite a lot of features (relationships, etc.). It was originally created because a lot of boilerplate code was written each time a kubernetes custom object had to be interfaced with python code.
Work on pykorm
is actually on the way. Don't hesitate to contribute to the
project if you have the energy for it !
Equivalences
Python | Kubernetes |
---|---|
Class | CustomResourceDefinition |
Instance | CustomResource |
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