135 lines
4.1 KiB
Python
135 lines
4.1 KiB
Python
# Copyright 2019 The Kubernetes Authors.
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#
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# Licensed under the Apache License, Version 2.0 (the "License");
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# you may not use this file except in compliance with the License.
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# You may obtain a copy of the License at
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#
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# http://www.apache.org/licenses/LICENSE-2.0
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#
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# Unless required by applicable law or agreed to in writing, software
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# distributed under the License is distributed on an "AS IS" BASIS,
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# WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
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# See the License for the specific language governing permissions and
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# limitations under the License.
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"""
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Shows the functionality of exec using a Busybox container.
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"""
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import time
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from kubernetes import config
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from kubernetes.client import Configuration
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from kubernetes.client.api import core_v1_api
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from kubernetes.client.rest import ApiException
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from kubernetes.stream import stream
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def exec_commands(api_instance):
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name = 'busybox-test'
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resp = None
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try:
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resp = api_instance.read_namespaced_pod(name=name,
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namespace='default')
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except ApiException as e:
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if e.status != 404:
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print(f"Unknown error: {e}")
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exit(1)
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if not resp:
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print(f"Pod {name} does not exist. Creating it...")
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pod_manifest = {
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'apiVersion': 'v1',
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'kind': 'Pod',
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'metadata': {
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'name': name
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},
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'spec': {
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'containers': [{
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'image': 'busybox',
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'name': 'sleep',
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"args": [
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"/bin/sh",
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"-c",
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"while true;do date;sleep 5; done"
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]
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}]
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}
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}
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resp = api_instance.create_namespaced_pod(body=pod_manifest,
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namespace='default')
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while True:
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resp = api_instance.read_namespaced_pod(name=name,
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namespace='default')
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if resp.status.phase != 'Pending':
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break
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time.sleep(1)
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print("Done.")
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# Calling exec and waiting for response
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exec_command = [
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'/bin/sh',
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'-c',
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'echo This message goes to stderr; echo This message goes to stdout']
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# When calling a pod with multiple containers running the target container
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# has to be specified with a keyword argument container=<name>.
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resp = stream(api_instance.connect_get_namespaced_pod_exec,
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name,
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'default',
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command=exec_command,
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stderr=True, stdin=False,
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stdout=True, tty=False)
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print("Response: " + resp)
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# Calling exec interactively
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exec_command = ['/bin/sh']
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resp = stream(api_instance.connect_get_namespaced_pod_exec,
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name,
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'default',
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command=exec_command,
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stderr=True, stdin=True,
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stdout=True, tty=False,
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_preload_content=False)
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commands = [
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"echo This message goes to stdout",
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"echo \"This message goes to stderr\" >&2",
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]
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while resp.is_open():
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resp.update(timeout=1)
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if resp.peek_stdout():
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print(f"STDOUT: {resp.read_stdout()}")
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if resp.peek_stderr():
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print(f"STDERR: {resp.read_stderr()}")
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if commands:
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c = commands.pop(0)
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print(f"Running command... {c}\n")
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resp.write_stdin(c + "\n")
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else:
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break
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resp.write_stdin("date\n")
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sdate = resp.readline_stdout(timeout=3)
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print(f"Server date command returns: {sdate}")
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resp.write_stdin("whoami\n")
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user = resp.readline_stdout(timeout=3)
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print(f"Server user is: {user}")
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resp.close()
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def main():
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config.load_kube_config()
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try:
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c = Configuration().get_default_copy()
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except AttributeError:
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c = Configuration()
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c.assert_hostname = False
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Configuration.set_default(c)
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core_v1 = core_v1_api.CoreV1Api()
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exec_commands(core_v1)
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if __name__ == '__main__':
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main()
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