Module ssh2net.session_miko
ssh2net.session_miko
Expand source code
"""ssh2net.session_miko"""
import logging
import time
import warnings
from paramiko.ssh_exception import AuthenticationException
from ssh2net.exceptions import AuthenticationFailed, RequirementsNotSatisfied
class SSH2NetSessionParamiko:
def __init__(self, p_self):
"""
Initialize SSH2NetSessionParamiko Object
This object, through composition, allows for using Paramiko as the underlying "driver"
for SSH2Net instead of the default "ssh2-python". Paramiko will be ever so slightly slower
but as you will most likely be I/O constrained it shouldn't matter! "ssh2-python" as of
20 October 2019 has a bug preventing keyboard interactive authentication from working as
desired; this is the reason Paramiko is in here now!
Args:
p_self: SSH2Net object
Returns:
N/A # noqa
Raises:
N/A # noqa
"""
self.__dict__ = p_self.__dict__
self._session_alive = p_self._session_alive
self._session_open = p_self._session_open
self._channel_alive = p_self._channel_alive
def _session_open_connect(self) -> None:
"""
Perform session handshake for paramiko (instead of default ssh2-python)
Args:
N/A # noqa
Returns:
N/A # noqa
Raises:
RequirementsNotSatisfied: if paramiko is not installed
Exception: catch all for unknown exceptions during session handshake
"""
try:
from paramiko import Transport # noqa
except ModuleNotFoundError as exc:
err = f"Module '{exc.name}' not installed!"
msg = f"***** {err} {'*' * (80 - len(err))}"
fix = (
f"To resolve this issue, install '{exc.name}'. You can do this in one of the "
"following ways:\n"
"1: 'pip install -r requirements-paramiko.txt'\n"
"2: 'pip install ssh2net[paramiko]'"
)
warning = "\n" + msg + "\n" + fix + "\n" + msg
warnings.warn(warning)
raise RequirementsNotSatisfied
try:
self.session = Transport(self.sock)
self.session.start_client()
self.session.set_timeout = self._set_timeout
except Exception as exc:
logging.critical(
f"Failed to complete handshake with host {self.host}; " f"Exception: {exc}"
)
raise exc
def _session_public_key_auth(self) -> None:
"""
Perform public key based auth on SSH2NetSession
Args:
N/A # noqa
Returns:
N/A # noqa
Raises:
Exception: catch all for unhandled exceptions
"""
try:
self.session.auth_publickey(self.auth_user, self.auth_public_key)
except AuthenticationException:
logging.critical(f"Public key authentication with host {self.host} failed.")
except Exception as exc:
logging.critical(
"Unknown error occurred during public key authentication with host "
f"{self.host}; Exception: {exc}"
)
raise exc
def _session_password_auth(self) -> None:
"""
Perform password or keyboard interactive based auth on SSH2NetSession
Args:
N/A # noqa
Returns:
N/A # noqa
Raises:
AuthenticationFailed: if authentication fails
Exception: catch all for unknown other exceptions
"""
try:
self.session.auth_password(self.auth_user, self.auth_password)
except AuthenticationException as exc:
logging.critical(
f"Password authentication with host {self.host} failed. Exception: {exc}."
"\n\tNote: Paramiko automatically attempts both standard auth as well as keyboard "
"interactive auth. Paramiko exception about bad auth type may be misleading!"
)
raise AuthenticationFailed
except Exception as exc:
logging.critical(
"Unknown error occurred during password authentication with host "
f"{self.host}; Exception: {exc}"
)
raise exc
def _channel_open_driver(self) -> None:
"""
Open channel
Args:
N/A # noqa
Returns:
N/A # noqa
Raises:
N/A # noqa
"""
self.channel = self.session.open_session()
self.channel.get_pty()
logging.debug(f"Channel to host {self.host} opened")
def _channel_invoke_shell(self) -> None:
"""
Invoke shell on channel
Additionally, this "re-points" some ssh2net method calls to the appropriate paramiko
methods. This happens as ssh2net is primarily built on "ssh2-python" and there is not
full parity between paramiko/ssh2-python.
Args:
N/A # noqa
Returns:
N/A # noqa
Raises:
N/A # noqa
"""
self._shell = True
self.channel.invoke_shell()
self.channel.read = self._paramiko_read_channel
self.channel.write = self.channel.sendall
self.session.set_blocking = self._set_blocking
self.channel.flush = self._flush
def _paramiko_read_channel(self):
"""
Patch channel.read method for paramiko driver
"ssh2-python" returns a tuple of bytes and data, "paramiko" simply returns the data
from the channel, patch this for parity with "ssh2-python".
Args:
N/A # noqa
Returns:
N/A # noqa
Raises:
N/A # noqa
"""
channel_read = self.channel.recv(1024)
return None, channel_read
def _flush(self):
"""
Patch a "flush" method for paramiko driver
Need to investigate this further for two things:
1) is "flush" even necessary when using ssh2-python driver?
2) if it is necessary, is there a combination of reads/writes that would implement
this in a sane fashion for paramiko
Args:
N/A # noqa
Returns:
N/A # noqa
Raises:
N/A # noqa
"""
while True:
time.sleep(0.01)
if self.channel.recv_ready():
self._paramiko_read_channel()
else:
self.channel.write("\n")
return
def _set_blocking(self, blocking):
# Add docstring
# need to reset timeout because it seems paramiko sets it to 0 if you set to non blocking
# paramiko uses seconds instead of ms
self.channel.setblocking(blocking)
self.channel.settimeout(self.session_timeout / 1000)
def _set_timeout(self, timeout):
# paramiko uses seconds instead of ms
self.channel.settimeout(timeout / 1000)Classes
class SSH2NetSessionParamiko (p_self)-
Initialize SSH2NetSessionParamiko Object
This object, through composition, allows for using Paramiko as the underlying "driver" for SSH2Net instead of the default "ssh2-python". Paramiko will be ever so slightly slower but as you will most likely be I/O constrained it shouldn't matter! "ssh2-python" as of 20 October 2019 has a bug preventing keyboard interactive authentication from working as desired; this is the reason Paramiko is in here now!
Args
p_self- SSH2Net object
Returns
N/A#noqa
Raises
N/A#noqa
Expand source code
class SSH2NetSessionParamiko: def __init__(self, p_self): """ Initialize SSH2NetSessionParamiko Object This object, through composition, allows for using Paramiko as the underlying "driver" for SSH2Net instead of the default "ssh2-python". Paramiko will be ever so slightly slower but as you will most likely be I/O constrained it shouldn't matter! "ssh2-python" as of 20 October 2019 has a bug preventing keyboard interactive authentication from working as desired; this is the reason Paramiko is in here now! Args: p_self: SSH2Net object Returns: N/A # noqa Raises: N/A # noqa """ self.__dict__ = p_self.__dict__ self._session_alive = p_self._session_alive self._session_open = p_self._session_open self._channel_alive = p_self._channel_alive def _session_open_connect(self) -> None: """ Perform session handshake for paramiko (instead of default ssh2-python) Args: N/A # noqa Returns: N/A # noqa Raises: RequirementsNotSatisfied: if paramiko is not installed Exception: catch all for unknown exceptions during session handshake """ try: from paramiko import Transport # noqa except ModuleNotFoundError as exc: err = f"Module '{exc.name}' not installed!" msg = f"***** {err} {'*' * (80 - len(err))}" fix = ( f"To resolve this issue, install '{exc.name}'. You can do this in one of the " "following ways:\n" "1: 'pip install -r requirements-paramiko.txt'\n" "2: 'pip install ssh2net[paramiko]'" ) warning = "\n" + msg + "\n" + fix + "\n" + msg warnings.warn(warning) raise RequirementsNotSatisfied try: self.session = Transport(self.sock) self.session.start_client() self.session.set_timeout = self._set_timeout except Exception as exc: logging.critical( f"Failed to complete handshake with host {self.host}; " f"Exception: {exc}" ) raise exc def _session_public_key_auth(self) -> None: """ Perform public key based auth on SSH2NetSession Args: N/A # noqa Returns: N/A # noqa Raises: Exception: catch all for unhandled exceptions """ try: self.session.auth_publickey(self.auth_user, self.auth_public_key) except AuthenticationException: logging.critical(f"Public key authentication with host {self.host} failed.") except Exception as exc: logging.critical( "Unknown error occurred during public key authentication with host " f"{self.host}; Exception: {exc}" ) raise exc def _session_password_auth(self) -> None: """ Perform password or keyboard interactive based auth on SSH2NetSession Args: N/A # noqa Returns: N/A # noqa Raises: AuthenticationFailed: if authentication fails Exception: catch all for unknown other exceptions """ try: self.session.auth_password(self.auth_user, self.auth_password) except AuthenticationException as exc: logging.critical( f"Password authentication with host {self.host} failed. Exception: {exc}." "\n\tNote: Paramiko automatically attempts both standard auth as well as keyboard " "interactive auth. Paramiko exception about bad auth type may be misleading!" ) raise AuthenticationFailed except Exception as exc: logging.critical( "Unknown error occurred during password authentication with host " f"{self.host}; Exception: {exc}" ) raise exc def _channel_open_driver(self) -> None: """ Open channel Args: N/A # noqa Returns: N/A # noqa Raises: N/A # noqa """ self.channel = self.session.open_session() self.channel.get_pty() logging.debug(f"Channel to host {self.host} opened") def _channel_invoke_shell(self) -> None: """ Invoke shell on channel Additionally, this "re-points" some ssh2net method calls to the appropriate paramiko methods. This happens as ssh2net is primarily built on "ssh2-python" and there is not full parity between paramiko/ssh2-python. Args: N/A # noqa Returns: N/A # noqa Raises: N/A # noqa """ self._shell = True self.channel.invoke_shell() self.channel.read = self._paramiko_read_channel self.channel.write = self.channel.sendall self.session.set_blocking = self._set_blocking self.channel.flush = self._flush def _paramiko_read_channel(self): """ Patch channel.read method for paramiko driver "ssh2-python" returns a tuple of bytes and data, "paramiko" simply returns the data from the channel, patch this for parity with "ssh2-python". Args: N/A # noqa Returns: N/A # noqa Raises: N/A # noqa """ channel_read = self.channel.recv(1024) return None, channel_read def _flush(self): """ Patch a "flush" method for paramiko driver Need to investigate this further for two things: 1) is "flush" even necessary when using ssh2-python driver? 2) if it is necessary, is there a combination of reads/writes that would implement this in a sane fashion for paramiko Args: N/A # noqa Returns: N/A # noqa Raises: N/A # noqa """ while True: time.sleep(0.01) if self.channel.recv_ready(): self._paramiko_read_channel() else: self.channel.write("\n") return def _set_blocking(self, blocking): # Add docstring # need to reset timeout because it seems paramiko sets it to 0 if you set to non blocking # paramiko uses seconds instead of ms self.channel.setblocking(blocking) self.channel.settimeout(self.session_timeout / 1000) def _set_timeout(self, timeout): # paramiko uses seconds instead of ms self.channel.settimeout(timeout / 1000)