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Support the pod exec method using a subprocess.Popen like object.
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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. | ||
|
|
||
| """ | ||
| Examples of using kubernetes.stream.Popen, which exposes the pod exec call using a subprocess.Popen | ||
| like object, with support for both binary and text data. | ||
| kubernetes.stream.Popen Constructor | ||
| method - kubernetes api method, most likely connect_get_namespaced_pod_exec | ||
| name - name of the pod to exec in | ||
| namespace - namespace of the pod to exec in | ||
| command - command line to exec | ||
| container - container of the pod to exec in, only needed if more than one | ||
| stdin - stdin handling, True or PIPE creates self.stdin, DEVNULL enables but ignores | ||
| stdout - stdout handling, True or PIPE creates self.stdout, DEVNULL enables but ignores | ||
| stderr - stderr handling, True or PIPE creates self.stderr, STDOUT combines into stderr, DEVNULL enables but ignores | ||
| tty - True if a tty should be enabled | ||
| bufsize - stream buffer size, -1 is system default, 0 is unbuffered, 1 in text mode is line buffered | ||
| encoding - text encoding format | ||
| errors - text encoding error strictness | ||
| text - force enabling or disabling text mode, default is tty value if encoding and errors are not set | ||
| kubernetes.stream.Popen Fields | ||
| name - pod name | ||
| namespace - pod namespace | ||
| container - pod container | ||
| command - command run | ||
| tty - tty enabled | ||
| encodning - text mode encoding | ||
| errors - text mode errors strictness | ||
| stdin - if enabled, a writable io stream | ||
| stdout - if enabled, a readable io stream | ||
| stderr - if enabkedm a readable io stream | ||
| returncode - exec process return code when complete | ||
| result - full result object returned by kubernetes | ||
| closed - flag if the connecition is closed | ||
| timeout - timeout setting | ||
| kubernetes.stream.Popen Methods | ||
| communicate - same as subprocess.Popen.communicate | ||
| wait - same as subprocess.Popen.wait | ||
| resize - resize the tty width and height | ||
| close - close the kubernetes connection | ||
| """ | ||
|
|
||
| import os | ||
| import select | ||
| import sys | ||
| import termios | ||
| import time | ||
| import tty | ||
|
|
||
| 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 Popen, STDOUT | ||
|
|
||
| ############################################################################## | ||
| # | ||
| ############################################################################## | ||
|
|
||
| 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("Unknown error: %s" % e) | ||
| exit(1) | ||
|
|
||
| if not resp: | ||
| print("Pod %s does not exist. Creating it..." % name) | ||
| 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 | ||
| command = ['/bin/sh', '-c', 'echo This message goes to stdout; echo This message goes to stderr >&2'] | ||
| popen = Popen( | ||
| api_instance.connect_get_namespaced_pod_exec, | ||
| name, 'default', command=command, | ||
| stdin=False, stdout=True, stderr=True, | ||
| tty=False, text=True, | ||
| ) | ||
| stdout, stderr = popen.communicate() | ||
| print("STDOUT: " + stdout, end='', flush=True) | ||
| print("STDERR: " + stderr, end='', flush=True) | ||
|
|
||
| ################################################################## | ||
| # Calling a process interactively | ||
| popen = Popen( | ||
| api_instance.connect_get_namespaced_pod_exec, | ||
| name, 'default', command=['/bin/sh'], | ||
| stdin=True, stdout=True, stderr=True, | ||
| tty=False, text=True, bufsize=1, # bufsize=1 will flush on newlines | ||
| ) | ||
| commands = [ | ||
| "echo This message goes to stdout", | ||
| "echo This message goes to stderr >&2", | ||
| ] | ||
| # Do non-blocking stdout and stderr reads. | ||
| popen.timeout = 0 | ||
| while commands and not popen.closed: | ||
| line = commands.pop(0) | ||
| print("Running command... %s" % line, flush=True) | ||
| popen.stdin.write(line + "\n") | ||
| time.sleep(1) | ||
| try: | ||
| line = popen.stdout.readline() | ||
| print("STDOUT: %s" % line, end='', flush=True) | ||
| except TimeoutError: | ||
| pass | ||
| try: | ||
| line = popen.stderr.readline() | ||
| print("STERR: %s" % line, end='', flush=True) | ||
| except TimeoutError: | ||
| pass | ||
| popen.stdin.write("date\n") | ||
| popen.timeout = 3 | ||
| line = popen.stdout.readline() | ||
| print("Server date command returns: %s" % line) | ||
| popen.stdin.write("whoami\n") | ||
| popen.timeout = 3 | ||
| line = popen.stdout.readline() | ||
| print("Server user is: %s" % line) | ||
| popen.close() | ||
|
|
||
| ################################################################## | ||
| # Full TTY integration running top, uses local posix apis and raw i/o. | ||
| popen = Popen( | ||
| api_instance.connect_get_namespaced_pod_exec, | ||
| name, 'default', command=['top'], | ||
| stdin=True, stdout=True, stderr=STDOUT, # Send all stderr to stdout | ||
| tty=True, text=False, bufsize=0, # bufsize=0 will not buffer data | ||
| ) | ||
| stdin = sys.stdin.fileno() | ||
| tcattr = termios.tcgetattr(stdin) | ||
| size = None | ||
| stdout = sys.stdout.fileno() | ||
| # Do non-blocking stdout reads | ||
| popen.timeout = 0 | ||
| try: | ||
| # Enable raw tty mode with no echoing or buffering | ||
| tty.setraw(stdin) | ||
| while True: | ||
| resize = os.get_terminal_size() | ||
| if not size or resize.columns != size.columns or resize.lines != size.lines: | ||
| size = resize | ||
| # Inform remote top of the size of the terminal. | ||
| popen.resize(size.columns, size.lines) | ||
| # Check if there is anything from our stdin | ||
| r, _, _ = select.select([stdin], [], [], 0) | ||
| if r: | ||
| # Read from our stdin | ||
| data = os.read(stdin, 1024) | ||
| # Write it to remote top's stdin | ||
| popen.stdin.write(data) | ||
| try: | ||
| # Try to read from top's stdout | ||
| data = popen.stdout.read(1024) | ||
| # If a zero length data, then stdout has been closed | ||
| if not data: | ||
| break | ||
| # Write remote top's stdout to our stdout | ||
| os.write(stdout, data) | ||
| except TimeoutError: | ||
| # Nothing from stdout available at this time | ||
| pass | ||
| finally: | ||
| # Restore the original tty attributes from raw mode | ||
| termios.tcsetattr(stdin, termios.TCSANOW, tcattr) | ||
| # stdout was closed, now wait for top to finish. | ||
| popen.wait() | ||
|
|
||
|
|
||
| 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) | ||
|
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||
|
|
||
| if __name__ == '__main__': | ||
| main() |
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