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Merge pull request #1237 from iciclespider/port-forwarding
Unittests for portforwarding ability added in python-base.
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| # Copyright 2020 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. | ||
|
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| """ | ||
| Shows the functionality of portforward streaming using an nginx container. | ||
| """ | ||
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| import select | ||
| import socket | ||
| import time | ||
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| import six.moves.urllib.request as urllib_request | ||
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| 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 portforward | ||
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| ############################################################################## | ||
| # Kubernetes pod port forwarding works by directly providing a socket which | ||
| # the python application uses to send and receive data on. This is in contrast | ||
| # to the go client, which opens a local port that the go application then has | ||
| # to open to get a socket to transmit data. | ||
| # | ||
| # This simplifies the python application, there is not a local port to worry | ||
| # about if that port number is available. Nor does the python application have | ||
| # to then deal with opening this local port. The socket used to transmit data | ||
| # is immediately provided to the python application. | ||
| # | ||
| # Below also is an example of monkey patching the socket.create_connection | ||
| # function so that DNS names of the following formats will access kubernetes | ||
| # ports: | ||
| # | ||
| # <pod-name>.<namespace>.kubernetes | ||
| # <pod-name>.pod.<namespace>.kubernetes | ||
| # <service-name>.svc.<namespace>.kubernetes | ||
| # <service-name>.service.<namespace>.kubernetes | ||
| # | ||
| # These DNS name can be used to interact with pod ports using python libraries, | ||
| # such as urllib.request and http.client. For example: | ||
| # | ||
| # response = urllib.request.urlopen( | ||
| # 'https://metrics-server.service.kube-system.kubernetes/' | ||
| # ) | ||
| # | ||
| ############################################################################## | ||
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| def portforward_commands(api_instance): | ||
| name = 'portforward-example' | ||
| 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) | ||
|
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| if not resp: | ||
| print("Pod %s does not exist. Creating it..." % name) | ||
| pod_manifest = { | ||
| 'apiVersion': 'v1', | ||
| 'kind': 'Pod', | ||
| 'metadata': { | ||
| 'name': name | ||
| }, | ||
| 'spec': { | ||
| 'containers': [{ | ||
| 'image': 'nginx', | ||
| 'name': 'nginx', | ||
| }] | ||
| } | ||
| } | ||
| 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.") | ||
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| pf = portforward( | ||
| api_instance.connect_get_namespaced_pod_portforward, | ||
| name, 'default', | ||
| ports='80', | ||
| ) | ||
| http = pf.socket(80) | ||
| http.setblocking(True) | ||
| http.sendall(b'GET / HTTP/1.1\r\n') | ||
| http.sendall(b'Host: 127.0.0.1\r\n') | ||
| http.sendall(b'Connection: close\r\n') | ||
| http.sendall(b'Accept: */*\r\n') | ||
| http.sendall(b'\r\n') | ||
| response = b'' | ||
| while True: | ||
| select.select([http], [], []) | ||
| data = http.recv(1024) | ||
| if not data: | ||
| break | ||
| response += data | ||
| http.close() | ||
| print(response.decode('utf-8')) | ||
| error = pf.error(80) | ||
| if error is None: | ||
| print("No port forward errors on port 80.") | ||
| else: | ||
| print("Port 80 has the following error: %s" % error) | ||
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| # Monkey patch socket.create_connection which is used by http.client and | ||
| # urllib.request. The same can be done with urllib3.util.connection.create_connection | ||
| # if the "requests" package is used. | ||
| socket_create_connection = socket.create_connection | ||
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| def kubernetes_create_connection(address, *args, **kwargs): | ||
| dns_name = address[0] | ||
| if isinstance(dns_name, bytes): | ||
| dns_name = dns_name.decode() | ||
| dns_name = dns_name.split(".") | ||
| if dns_name[-1] != 'kubernetes': | ||
| return socket_create_connection(address, *args, **kwargs) | ||
| if len(dns_name) not in (3, 4): | ||
| raise RuntimeError("Unexpected kubernetes DNS name.") | ||
| namespace = dns_name[-2] | ||
| name = dns_name[0] | ||
| port = address[1] | ||
| if len(dns_name) == 4: | ||
| if dns_name[1] in ('svc', 'service'): | ||
| service = api_instance.read_namespaced_service(name, namespace) | ||
| for service_port in service.spec.ports: | ||
| if service_port.port == port: | ||
| port = service_port.target_port | ||
| break | ||
| else: | ||
| raise RuntimeError( | ||
| "Unable to find service port: %s" % port) | ||
| label_selector = [] | ||
| for key, value in service.spec.selector.items(): | ||
| label_selector.append("%s=%s" % (key, value)) | ||
| pods = api_instance.list_namespaced_pod( | ||
| namespace, label_selector=",".join(label_selector) | ||
| ) | ||
| if not pods.items: | ||
| raise RuntimeError("Unable to find service pods.") | ||
| name = pods.items[0].metadata.name | ||
| if isinstance(port, str): | ||
| for container in pods.items[0].spec.containers: | ||
| for container_port in container.ports: | ||
| if container_port.name == port: | ||
| port = container_port.container_port | ||
| break | ||
| else: | ||
| continue | ||
| break | ||
| else: | ||
| raise RuntimeError( | ||
| "Unable to find service port name: %s" % port) | ||
| elif dns_name[1] != 'pod': | ||
| raise RuntimeError( | ||
| "Unsupported resource type: %s" % | ||
| dns_name[1]) | ||
| pf = portforward(api_instance.connect_get_namespaced_pod_portforward, | ||
| name, namespace, ports=str(port)) | ||
| return pf.socket(port) | ||
| socket.create_connection = kubernetes_create_connection | ||
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| # Access the nginx http server using the | ||
| # "<pod-name>.pod.<namespace>.kubernetes" dns name. | ||
| response = urllib_request.urlopen( | ||
| 'http://%s.pod.default.kubernetes' % name) | ||
| html = response.read().decode('utf-8') | ||
| response.close() | ||
| print('Status Code: %s' % response.code) | ||
| print(html) | ||
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| def main(): | ||
| config.load_kube_config() | ||
| c = Configuration.get_default_copy() | ||
| c.assert_hostname = False | ||
| Configuration.set_default(c) | ||
| core_v1 = core_v1_api.CoreV1Api() | ||
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| portforward_commands(core_v1) | ||
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| if __name__ == '__main__': | ||
| main() |
Submodule base
updated
3 files
| +1 −1 | stream/__init__.py | |
| +22 −18 | stream/stream.py | |
| +260 −55 | stream/ws_client.py |
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