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