lightkube 0.21.0

Lightweight kubernetes client library

lightkube

Modern lightweight kubernetes module for python

Highlights

• Simple interface shared across all kubernetes APIs.
• Extensive type hints to avoid common mistakes and to support autocompletion.
• Models and resources generated from the swagger specifications using standard dataclasses.
• Load/Dump resource objects from YAML.
• Support for async/await
• Support for installing a specific version of the kubernetes models (1.20 to 1.35)
• Lazy instantiation of inner models.
• Fast startup and small memory footprint as only needed models and resources can be imported.
• Automatic handling of pagination when listing resources.

This module is powered by httpx.

Installation

This module requires python >= 3.8

pip install lightkube

Usage

List

Read a pod

from lightkube import Client
from lightkube.resources.core_v1 import Pod

client = Client()
pod = client.get(Pod, name="my-pod", namespace="default")
print(pod.namespace.uid)

List nodes

from lightkube import Client
from lightkube.resources.core_v1 import Node

client = Client()
for node in client.list(Node):
    print(node.metadata.name)

Create

Create a config map

from lightkube import Client
from lightkube.resources.core_v1 import ConfigMap
from lightkube.models.meta_v1 import ObjectMeta

client = Client()
config = ConfigMap(
    metadata=ObjectMeta(name='my-config', namespace='default'),
    data={'key1': 'value1', 'key2': 'value2'}
)

client.create(config)

Create resources defined in a file

from lightkube import Client, codecs

client = Client()
with open('deployment.yaml') as f:
    for obj in codecs.load_all_yaml(f):
        client.create(obj)

Modify

Replace the previous config with a different content

config.data['key1'] = 'new value'
client.replace(config)

Patch an existing config adding more data

patch = {"data": {"key3": "value3"}}
client.patch(ConfigMap, name="my-config", obj=patch)

Remove the just added data key key3

# When using PatchType.MERGE, setting a value of a key/value to None, will remove the current item 
patch = {'metadata': {"key3": None}}
client.patch(ConfigMap, name='my-config', namespace='default', obj=patch, patch_type=PatchType.MERGE)

Add a label

client.set(ConfigMap, name="my-config", labels={'env': 'prod'})

Remove a label

client.set(ConfigMap, name="my-config", labels={'env': None})

Scale a deployment

from lightkube import Client
from lightkube.resources.apps_v1 import Deployment
from lightkube.models.meta_v1 import ObjectMeta
from lightkube.models.autoscaling_v1 import ScaleSpec

client = Client()
obj = Deployment.Scale(
    metadata=ObjectMeta(name='metrics-server', namespace='kube-system'),
    spec=ScaleSpec(replicas=1)
)
client.replace(obj)

Update Status of a deployment

from lightkube import Client
from lightkube.resources.apps_v1 import Deployment
from lightkube.models.apps_v1 import DeploymentStatus

client = Client()
obj = Deployment.Status(
    status=DeploymentStatus(observedGeneration=99)
)
client.apply(obj, name='metrics-server', namespace='kube-system')

Create and modify resources using server side apply

Note: field_manager is required for server-side apply. You can specify it once in the client constructor or when calling apply(). Also apiVersion and kind need to be provided as part of the object definition.

from lightkube.resources.core_v1 import ConfigMap
from lightkube.models.meta_v1 import ObjectMeta

client = Client(field_manager="my-manager")
config = ConfigMap(
    # note apiVersion and kind need to be specified for server-side apply
    apiVersion='v1', kind='ConfigMap',
    metadata=ObjectMeta(name='my-config', namespace='default'),
    data={'key1': 'value1', 'key2': 'value2'}
)

res = client.apply(config)
print(res.data)
# prints {'key1': 'value1', 'key2': 'value2'}

del config.data['key1']
config.data['key3'] = 'value3'

res = client.apply(config)
print(res.data)
# prints {'key2': 'value2', 'key3': 'value3'}

Delete

Delete a namespaced resource

client.delete(ConfigMap, name='my-config', namespace='default')

Monitoring & Interaction

Watch deployments

from lightkube import Client
from lightkube.resources.apps_v1 import Deployment

client = Client()
for op, dep in client.watch(Deployment, namespace="default"):
    print(f"{dep.namespace.name} {dep.spec.replicas}")

Stream pod logs

from lightkube import Client

client = Client()
for line in client.log('my-pod', follow=True):
    print(line)

Execute a command inside a pod

from lightkube import Client

client = Client()

# Capture stdout or raise ApiError if error code is != 0
res = client.exec('my-pod', namespace='default', container='main', command=['ls', '-l', '/'], 
    stdout=True, raise_on_error=True)
print(res.stdout)

# Send data to stdin and capture output
res = client.exec('my-pod', namespace='default', container='main', command=['cat'], 
    stdin='hello\n', stdout=True)
print(res.stdout)
print(res.exit_code)

Unsupported features

The following features are not supported at the moment:

• Special subresources attach, portforward and proxy.
• auth-provider authentication method is not supported. The supported authentication methods are token, tokenFile, username + password and exec.