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https://github.com/avatao-content/baseimage-tutorial-framework
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89 lines
2.8 KiB
Python
89 lines
2.8 KiB
Python
# Copyright (C) 2018 Avatao.com Innovative Learning Kft.
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# All Rights Reserved. See LICENSE file for details.
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import logging
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from tfw.event_handlers import FrontendEventHandlerBase
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from tfw.components.terminado_mini_server import TerminadoMiniServer
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from tfw.config import TFWENV
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from tao.config import TAOENV
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LOG = logging.getLogger(__name__)
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class TerminalEventHandler(FrontendEventHandlerBase):
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"""
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Event handler responsible for managing terminal sessions for frontend xterm
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sessions to connect to. You need to instanciate this in order for frontend
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terminals to work.
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This EventHandler accepts messages that have a data['command'] key specifying
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a command to be executed.
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The API of each command is documented in their respective handler.
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"""
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def __init__(self, key, monitor):
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"""
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:param key: key this EventHandler listens to
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:param monitor: tfw.components.HistoryMonitor instance to read command history from
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"""
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super().__init__(key)
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self._historymonitor = monitor
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bash_as_user_cmd = ['sudo', '-u', TAOENV.USER, 'bash']
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self.terminado_server = TerminadoMiniServer(
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'/terminal',
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TFWENV.TERMINADO_PORT,
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TFWENV.TERMINADO_WD,
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bash_as_user_cmd
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)
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self.commands = {
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'write': self.write,
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'read': self.read
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}
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if self._historymonitor:
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self._historymonitor.start()
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self.terminado_server.listen()
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@property
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def historymonitor(self):
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return self._historymonitor
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def handle_event(self, message):
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try:
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data = message['data']
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message['data'] = self.commands[data['command']](data)
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return message
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except KeyError:
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LOG.error('IGNORING MESSAGE: Invalid message received: %s', message)
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def write(self, data):
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"""
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Writes a string to the terminal session (on the pty level).
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Useful for pre-typing and executing commands for the user.
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:param data: TFW message data containing 'value'
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(command to be written to the pty)
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"""
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self.terminado_server.pty.write(data['value'])
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return data
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def read(self, data):
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"""
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Reads the history of commands executed.
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:param data: TFW message data containing 'count'
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(the number of history elements to return)
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:return dict: message with list of commands in data['history']
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"""
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data['count'] = int(data.get('count', 1))
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if self.historymonitor:
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data['history'] = self.historymonitor.history[-data['count']:]
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return data
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def cleanup(self):
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self.terminado_server.stop()
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if self.historymonitor:
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self.historymonitor.stop()
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