python/kubernetes/client/ws_client.py

240 lines
8.6 KiB
Python

# 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.
from .rest import ApiException
import select
import certifi
import time
import collections
from websocket import WebSocket, ABNF, enableTrace
import six
import ssl
from six.moves.urllib.parse import urlencode
from six.moves.urllib.parse import quote_plus
STDIN_CHANNEL = 0
STDOUT_CHANNEL = 1
STDERR_CHANNEL = 2
class WSClient:
def __init__(self, configuration, url, headers):
"""A websocket client with support for channels.
Exec command uses different channels for different streams. for
example, 0 is stdin, 1 is stdout and 2 is stderr. Some other API calls
like port forwarding can forward different pods' streams to different
channels.
"""
enableTrace(False)
header = []
self._connected = False
self._channels = {}
self._all = ""
# We just need to pass the Authorization, ignore all the other
# http headers we get from the generated code
if headers and 'authorization' in headers:
header.append("authorization: %s" % headers['authorization'])
if url.startswith('wss://') and configuration.verify_ssl:
ssl_opts = {
'cert_reqs': ssl.CERT_REQUIRED,
'keyfile': configuration.key_file,
'certfile': configuration.cert_file,
'ca_certs': configuration.ssl_ca_cert or certifi.where(),
}
if configuration.assert_hostname is not None:
ssl_opts['check_hostname'] = configuration.assert_hostname
else:
ssl_opts = {'cert_reqs': ssl.CERT_NONE}
self.sock = WebSocket(sslopt=ssl_opts, skip_utf8_validation=False)
self.sock.connect(url, header=header)
self._connected = True
def peek_channel(self, channel, timeout=0):
"""Peek a channel and return part of the input,
empty string otherwise."""
self.update(timeout=timeout)
if channel in self._channels:
return self._channels[channel]
return ""
def read_channel(self, channel, timeout=0):
"""Read data from a channel."""
if channel not in self._channels:
ret = self.peek_channel(channel, timeout)
else:
ret = self._channels[channel]
if channel in self._channels:
del self._channels[channel]
return ret
def readline_channel(self, channel, timeout=None):
"""Read a line from a channel."""
if timeout is None:
timeout = float("inf")
start = time.time()
while self.is_open() and time.time() - start < timeout:
if channel in self._channels:
data = self._channels[channel]
if "\n" in data:
index = data.find("\n")
ret = data[:index]
data = data[index+1:]
if data:
self._channels[channel] = data
else:
del self._channels[channel]
return ret
self.update(timeout=(timeout - time.time() + start))
def write_channel(self, channel, data):
"""Write data to a channel."""
self.sock.send(chr(channel) + data)
def peek_stdout(self, timeout=0):
"""Same as peek_channel with channel=1."""
return self.peek_channel(STDOUT_CHANNEL, timeout=timeout)
def read_stdout(self, timeout=None):
"""Same as read_channel with channel=1."""
return self.read_channel(STDOUT_CHANNEL, timeout=timeout)
def readline_stdout(self, timeout=None):
"""Same as readline_channel with channel=1."""
return self.readline_channel(STDOUT_CHANNEL, timeout=timeout)
def peek_stderr(self, timeout=0):
"""Same as peek_channel with channel=2."""
return self.peek_channel(STDERR_CHANNEL, timeout=timeout)
def read_stderr(self, timeout=None):
"""Same as read_channel with channel=2."""
return self.read_channel(STDERR_CHANNEL, timeout=timeout)
def readline_stderr(self, timeout=None):
"""Same as readline_channel with channel=2."""
return self.readline_channel(STDERR_CHANNEL, timeout=timeout)
def read_all(self):
"""Read all of the inputs with the same order they recieved. The channel
information would be part of the string. This is useful for
non-interactive call where a set of command passed to the API call and
their result is needed after the call is concluded.
TODO: Maybe we can process this and return a more meaningful map with
channels mapped for each input.
"""
out = self._all
self._all = ""
self._channels = {}
return out
def is_open(self):
"""True if the connection is still alive."""
return self._connected
def write_stdin(self, data):
"""The same as write_channel with channel=0."""
self.write_channel(STDIN_CHANNEL, data)
def update(self, timeout=0):
"""Update channel buffers with at most one complete frame of input."""
if not self.is_open():
return
if not self.sock.connected:
self._connected = False
return
r, _, _ = select.select(
(self.sock.sock, ), (), (), timeout)
if r:
op_code, frame = self.sock.recv_data_frame(True)
if op_code == ABNF.OPCODE_CLOSE:
self._connected = False
return
elif op_code == ABNF.OPCODE_BINARY or op_code == ABNF.OPCODE_TEXT:
data = frame.data
if six.PY3:
data = data.decode("utf-8")
if len(data) > 1:
channel = ord(data[0])
data = data[1:]
if data:
# keeping all messages in the order they received for
# non-blocking call.
self._all += data
if channel not in self._channels:
self._channels[channel] = data
else:
self._channels[channel] += data
def run_forever(self, timeout=None):
"""Wait till connection is closed or timeout reached. Buffer any input
received during this time."""
if timeout:
start = time.time()
while self.is_open() and time.time() - start < timeout:
self.update(timeout=(timeout - time.time() + start))
else:
while self.is_open():
self.update(timeout=None)
WSResponse = collections.namedtuple('WSResponse', ['data'])
def websocket_call(configuration, url, query_params, _request_timeout,
_preload_content, headers):
"""An internal function to be called in api-client when a websocket
connection is required."""
# switch protocols from http to websocket
url = url.replace('http://', 'ws://')
url = url.replace('https://', 'wss://')
# patch extra /
url = url.replace('//api', '/api')
# Extract the command from the list of tuples
commands = None
for key, value in query_params:
if key == 'command':
commands = value
break
# drop command from query_params as we will be processing it separately
query_params = [(key, value) for key, value in query_params if
key != 'command']
# if we still have query params then encode them
if query_params:
url += '?' + urlencode(query_params)
# tack on the actual command to execute at the end
if isinstance(commands, list):
for command in commands:
url += "&command=%s&" % quote_plus(command)
else:
url += '&command=' + quote_plus(commands)
try:
client = WSClient(configuration, url, headers)
if not _preload_content:
return client
client.run_forever(timeout=_request_timeout)
return WSResponse('%s' % ''.join(client.read_all()))
except (Exception, KeyboardInterrupt, SystemExit) as e:
raise ApiException(status=0, reason=str(e))