Source code for tbot.machine.connector.paramiko

# tbot, Embedded Automation Tool
# Copyright (C) 2019  Harald Seiler
# This program is free software: you can redistribute it and/or modify
# it under the terms of the GNU General Public License as published by
# the Free Software Foundation, either version 3 of the License, or
# (at your option) any later version.
# This program is distributed in the hope that it will be useful,
# but WITHOUT ANY WARRANTY; without even the implied warranty of
# GNU General Public License for more details.
# You should have received a copy of the GNU General Public License
# along with this program.  If not, see <>.

import abc
import getpass
import paramiko
import pathlib
import typing
import contextlib

import tbot
from .. import channel
from ..linux import auth
from . import connector

Self = typing.TypeVar("Self", bound="ParamikoConnector")

[docs]class ParamikoConnector(connector.Connector): """ Connect to an ssh server using `Paramiko`_. .. _Paramiko: When inheriting from this connector, you should overwrite the attributes documented below to make it connect to your remote. **Example**: .. code-block:: python from tbot.machine import connector, linux class MyMachine( connector.ParamikoConnector, linux.Bash, ): hostname = "" username = "tbot-user" with MyMachine() as remotehost: remotehost.exec0("uname", "-a") """ __slots__ = ("_client", "_config") @property @abc.abstractmethod def hostname(self) -> str: """ Hostname of this remote. You must always specify this parameter in your Lab config! """ pass @property def username(self) -> str: """ Username to log in as. Defaults to the username from ``~/.ssh/config`` or the local username. """ if "user" in self._config: assert isinstance(self._config["user"], str) return self._config["user"] else: return getpass.getuser() @property def authenticator(self) -> auth.Authenticator: """ Return an authenticator that allows logging in on this machine. See :mod:`tbot.machine.linux.auth` for available authenticators. :rtype: tbot.machine.linux.auth.Authenticator """ if "identityfile" in self._config: assert isinstance(self._config["identityfile"], list) return auth.PrivateKeyAuthenticator( pathlib.Path(self._config["identityfile"][0]) ) return auth.NoneAuthenticator() @property def port(self) -> int: """ Port the remote SSH server is listening on. Defaults to ``22`` or the value of ``Port`` in ``~/.ssh/config``. """ if "port" in self._config: assert isinstance(self._config["port"], str) return int(self._config["port"]) else: return 22 @property def ignore_hostkey(self) -> bool: """ Ignore remote host key. Set this to true if the remote changes its host key often. Defaults to ``False`` or the value of ``StrictHostKeyChecking`` in ``~/.ssh/config``. """ if "stricthostkeychecking" in self._config: assert isinstance(self._config["stricthostkeychecking"], str) return self._config["stricthostkeychecking"] == "no" else: return False def __repr__(self) -> str: return ( f"<{self.__class__.__name__} {self.username}@{self.hostname}:{self.port}>" ) def __init__(self, other: "typing.Optional[ParamikoConnector]" = None) -> None: """ :param ParamikoConnector other: Build this connection by opening a new channel in an existing ssh-connection. """ self._client: typing.Optional[paramiko.SSHClient] = None self._config: typing.Dict[str, typing.Union[str, typing.List[str]]] = {} if other is not None: self._client = other._client self._config = other._config
[docs] @classmethod @contextlib.contextmanager def from_context( cls: typing.Type[Self], ctx: "tbot.Context" ) -> typing.Iterator[Self]: with cls() as m: yield m
def _connect(self) -> channel.Channel: if self._client is None: self._client = paramiko.SSHClient() try: c = paramiko.config.SSHConfig() with open(pathlib.Path.home() / ".ssh" / "config") as cfg: c.parse(cfg) self._config = c.lookup(self.hostname) except FileNotFoundError: # Config file does not exist pass except Exception as e: # Invalid config tbot.log.warning( tbot.log.c("Invalid").red + f" .ssh/config: {str(e):s}" ) raise if self.ignore_hostkey: self._client.set_missing_host_key_policy( paramiko.client.AutoAddPolicy() ) else: self._client.load_system_host_keys() password = None key_file = None authenticator = self.authenticator if isinstance(authenticator, auth.NoneAuthenticator): pass elif isinstance(authenticator, auth.PrivateKeyAuthenticator): key_file = authenticator.get_key_for_host(None) elif isinstance(authenticator, auth.PasswordAuthenticator): password = authenticator.password else: if typing.TYPE_CHECKING: authenticator._undefined_marker raise ValueError(f"Unknown authenticator {authenticator!r}") tbot.log.message( "Logging in on " + tbot.log.c(f"{self.username}@{self.hostname}:{self.port}").yellow + " ...", verbosity=tbot.log.Verbosity.COMMAND, ) if "hostname" in self._config: hostname = str(self._config["hostname"]) else: hostname = self.hostname self._client.connect( hostname, username=self.username, port=self.port, password=password, key_filename=key_file, ) return channel.ParamikoChannel(self._client.get_transport().open_session())
[docs] def clone(self: Self) -> Self: """ Clone this machine. Note that an ssh-session cannot hold an unlimited number of channels so cloning too much might lead to issues. The exact limit is dependent on the server configuration. """ new = type(self)(self) new._orig = self._orig or self return new