Kubernetes python client equivalent of "kubectl wait --for " command

Question

I am using kubernetes-client/python and want to write a method which will block control until a set of Pods is in Ready state (Running state). I found that kubernetes supports wait --for command for doing same thing via command. Can someone please help me with how to achieve same functionality using kubernetes python client.

To be precise i am mostly interested in equivalent of-

kubectl wait --for condition=Ready pod -l 'app in (kafka,elasticsearch)'

Answer 1

You can use the watch functionality available in the client library.

from kubernetes import client, config, watch

config.load_kube_config()
w = watch.Watch()
core_v1 = client.CoreV1Api()
for event in w.stream(func=core_v1.list_namespaced_pod,
                          namespace=namespace,
                          label_selector=label,
                          timeout_seconds=60):
    if event["object"].status.phase == "Running":
        w.stop()
        end_time = time.time()
        logger.info("%s started in %0.2f sec", full_name, end_time-start_time)
        return
    # event.type: ADDED, MODIFIED, DELETED
    if event["type"] == "DELETED":
        # Pod was deleted while we were waiting for it to start.
        logger.debug("%s deleted before it started", full_name)
        w.stop()
        return