Tulips

A small wrapper around https://github.com/kubernetes-client/python which understands Kubernetes charts.

Why

I needed something simple that would read Helm charts and push them to the Kubernetes cluster and be extensible. So something like helm+kubectl with ability to write you own tools around them.

Supported CRDS aka Kubernetes resources

• Deployment
• Service
• Ingress
• Secret
• Issuer (cert-manager)
• PersistentVolumeClaim

Example use

import yaml
from tulips.resources import ResourceRegistry
from kubernetes import client as k8s
from kubernetes import config


client = config.new_client_from_config('kube.conf')

spec = yaml.load('ingress.yaml')

ingress_cls = ResourceRegistry.get_cls(spec['kind'])
ingress = ingress_cls(config.client, namespace='default', spec)
ingress.create()  # Create Ingress resource
ingress.delete()  # Delete Ingress resource

Adding new resource

In order to add support for new Kubernetes resource, one needs to create class that inherits from tulips.resources.Resource class.

Example resource

import tulips.resources.Resource

class ClusterIssuer(Resource):
    """A `cert-manager` ClusterIssuer resource."""

    version = "v1alpha1"
    group = "certmanager.k8s.io"
    plural = "clusterissuers"

    def delete(self, body: k8s.V1DeleteOptions):
        return k8s.CustomObjectsApi(
            self.client
        ).delete_namespaced_custom_object(
            body=body,
            namespace=self.namespace,
            version=self.version,
            group=self.group,
            plural=self.plural,
            name=self.name,
        )

    def create(self):
        return k8s.CustomObjectsApi(
            self.client
        ).create_namespaced_custom_object(
            body=self.resource,
            namespace=self.namespace,
            version=self.version,
            group=self.group,
            plural=self.plural,
        )

It will be registered into the ResourceRegistry and can be fetched via ResourceRegistry.get_cls method.

Tulip

Tulip is a sample client that emulates Helm but without tiller.

$ python tulips push --help                                    06/25/18 -  9:49
Usage: tulips push [OPTIONS] CHART

  You can pass chart variables via foo=bar, for example '$ tulip push
  app.yaml foo=bar'

Options:
  --namespace TEXT   Kubernetes namespace
  --release TEXT     Name of the release
  --kubeconfig PATH  Path to kubernetes config
  --help             Show this message and exit.

Example client

Let's say that I want to deploy a Secret and Ingress

apiVersion: v1
kind: Secret
metadata:
  name: {{ release }}-secrets
type: Opaque
data:
  password: {{ @pwd }}
---
apiVersion: networking.k8s.io/v1
kind: Ingress
metadata:
  name: {{ release }}-web-ingress
  labels:
    app: woocart-{{ release }}
  annotations:
    nginx.ingress.kubernetes.io/limit-connections: "100"
    kubernetes.io/ingress.class: nginx
spec:
  defaultBackend:
    service:
      name: {{ release }}-web-ingress
      port:
        number: 80
  rules:
  - host: {{ domain }}
    http:
      paths:
        - path: /
          pathType: ImplementationSpecific
          backend:
            service:
              name: {{ release }}-web
            port:
              number: 80

If one runs `tulip --release test push --kubeconf kube.conf app.yaml domain=test.tld'

Spec file is inspected and all {{ variables }} are replaced with real values. Also special {{ @pwd }} will generate strong password using passlib library.