mirror of https://github.com/F-Stack/f-stack.git
134 lines
4.2 KiB
Python
134 lines
4.2 KiB
Python
# SPDX-License-Identifier: BSD-3-Clause
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# Copyright(c) 2023 PANTHEON.tech s.r.o.
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import socket
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import traceback
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from pathlib import PurePath
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from fabric import Connection # type: ignore[import]
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from invoke.exceptions import ( # type: ignore[import]
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CommandTimedOut,
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ThreadException,
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UnexpectedExit,
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)
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from paramiko.ssh_exception import ( # type: ignore[import]
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AuthenticationException,
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BadHostKeyException,
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NoValidConnectionsError,
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SSHException,
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)
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from framework.config import NodeConfiguration
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from framework.exception import SSHConnectionError, SSHSessionDeadError, SSHTimeoutError
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from framework.logger import DTSLOG
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from .remote_session import CommandResult, RemoteSession
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class SSHSession(RemoteSession):
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"""A persistent SSH connection to a remote Node.
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The connection is implemented with the Fabric Python library.
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Args:
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node_config: The configuration of the Node to connect to.
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session_name: The name of the session.
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logger: The logger used for logging.
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This should be passed from the parent OSSession.
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Attributes:
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session: The underlying Fabric SSH connection.
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Raises:
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SSHConnectionError: The connection cannot be established.
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"""
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session: Connection
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def __init__(
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self,
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node_config: NodeConfiguration,
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session_name: str,
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logger: DTSLOG,
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):
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super(SSHSession, self).__init__(node_config, session_name, logger)
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def _connect(self) -> None:
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errors = []
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retry_attempts = 10
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login_timeout = 20 if self.port else 10
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for retry_attempt in range(retry_attempts):
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try:
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self.session = Connection(
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self.ip,
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user=self.username,
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port=self.port,
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connect_kwargs={"password": self.password},
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connect_timeout=login_timeout,
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)
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self.session.open()
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except (ValueError, BadHostKeyException, AuthenticationException) as e:
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self._logger.exception(e)
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raise SSHConnectionError(self.hostname) from e
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except (NoValidConnectionsError, socket.error, SSHException) as e:
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self._logger.debug(traceback.format_exc())
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self._logger.warning(e)
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error = repr(e)
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if error not in errors:
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errors.append(error)
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self._logger.info(f"Retrying connection: retry number {retry_attempt + 1}.")
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else:
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break
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else:
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raise SSHConnectionError(self.hostname, errors)
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def is_alive(self) -> bool:
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return self.session.is_connected
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def _send_command(self, command: str, timeout: float, env: dict | None) -> CommandResult:
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"""Send a command and return the result of the execution.
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Args:
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command: The command to execute.
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timeout: Wait at most this many seconds for the execution to complete.
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env: Extra environment variables that will be used in command execution.
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Raises:
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SSHSessionDeadError: The session died while executing the command.
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SSHTimeoutError: The command execution timed out.
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"""
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try:
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output = self.session.run(command, env=env, warn=True, hide=True, timeout=timeout)
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except (UnexpectedExit, ThreadException) as e:
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self._logger.exception(e)
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raise SSHSessionDeadError(self.hostname) from e
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except CommandTimedOut as e:
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self._logger.exception(e)
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raise SSHTimeoutError(command, e.result.stderr) from e
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return CommandResult(self.name, command, output.stdout, output.stderr, output.return_code)
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def copy_from(
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self,
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source_file: str | PurePath,
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destination_file: str | PurePath,
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) -> None:
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self.session.get(str(destination_file), str(source_file))
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def copy_to(
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self,
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source_file: str | PurePath,
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destination_file: str | PurePath,
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) -> None:
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self.session.put(str(source_file), str(destination_file))
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def _close(self, force: bool = False) -> None:
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self.session.close()
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