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| 1 | +# Copyright 2025 The Kubernetes Authors. |
| 2 | +# |
| 3 | +# Licensed under the Apache License, Version 2.0 (the "License"); |
| 4 | +# you may not use this file except in compliance with the License. |
| 5 | +# You may obtain a copy of the License at |
| 6 | +# |
| 7 | +# http://www.apache.org/licenses/LICENSE-2.0 |
| 8 | +# |
| 9 | +# Unless required by applicable law or agreed to in writing, software |
| 10 | +# distributed under the License is distributed on an "AS IS" BASIS, |
| 11 | +# WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied. |
| 12 | +# See the License for the specific language governing permissions and |
| 13 | +# limitations under the License. |
| 14 | + |
| 15 | +""" |
| 16 | +Uses watch to print a stream of Pod events from the default namespace. |
| 17 | +The allow_watch_bookmarks flag is set to True, so the API server can send |
| 18 | +BOOKMARK events. |
| 19 | +
|
| 20 | +If the connection to the API server is lost, the script will reconnect and |
| 21 | +resume watching from the most recently received resource version. |
| 22 | +
|
| 23 | +For more information, see: |
| 24 | +- https://kubernetes.io/docs/reference/using-api/api-concepts/#efficient-detection-of-changes |
| 25 | +- https://kubernetes.io/docs/reference/using-api/api-concepts/#semantics-for-watch |
| 26 | +""" |
| 27 | + |
| 28 | +import urllib3 |
| 29 | + |
| 30 | +from kubernetes import config |
| 31 | +from kubernetes.client import api_client |
| 32 | +from kubernetes.client.exceptions import ApiException |
| 33 | +from kubernetes.dynamic.client import DynamicClient |
| 34 | + |
| 35 | +NAMESPACE = "default" |
| 36 | + |
| 37 | + |
| 38 | +def main(): |
| 39 | + # Configs can be set in Configuration class directly or using helper |
| 40 | + # utility. If no argument provided, the config will be loaded from |
| 41 | + # default location. |
| 42 | + config.load_kube_config() |
| 43 | + client = DynamicClient(api_client.ApiClient()) |
| 44 | + api = client.resources.get(api_version="v1", kind="Pod") |
| 45 | + |
| 46 | + # Setting resource_version=None means the server will send synthetic |
| 47 | + # ADDED events for all resources that exist when the watch starts. |
| 48 | + resource_version = None |
| 49 | + while True: |
| 50 | + try: |
| 51 | + for event in api.watch( |
| 52 | + namespace=NAMESPACE, |
| 53 | + resource_version=resource_version, |
| 54 | + allow_watch_bookmarks=True, |
| 55 | + ): |
| 56 | + # Remember the last resourceVersion we saw, so we can resume |
| 57 | + # watching from there if the connection is lost. |
| 58 | + resource_version = event['object'].metadata.resourceVersion |
| 59 | + |
| 60 | + print("Event: %s %s %s" % ( |
| 61 | + resource_version, |
| 62 | + event['type'], |
| 63 | + event['object'].metadata.name, |
| 64 | + )) |
| 65 | + |
| 66 | + except ApiException as err: |
| 67 | + if err.status == 410: |
| 68 | + print("ERROR: The requested resource version is no longer available.") |
| 69 | + resource_version = None |
| 70 | + else: |
| 71 | + raise |
| 72 | + |
| 73 | + except urllib3.exceptions.ProtocolError: |
| 74 | + print("Lost connection to the k8s API server. Reconnecting...") |
| 75 | + |
| 76 | + |
| 77 | +if __name__ == "__main__": |
| 78 | + main() |
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