131 lines
4.0 KiB
Python
131 lines
4.0 KiB
Python
# linux shell command execution utility
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#
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# Copyright (C) 2020 Eric Callahan <arksine.code@gmail.com>
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#
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# This file may be distributed under the terms of the GNU GPLv3 license.
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import os
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import shlex
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import subprocess
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import logging
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from tornado import gen
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from tornado.ioloop import IOLoop
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class ShellCommand:
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def __init__(self, cmd, callback):
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self.io_loop = IOLoop.current()
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self.name = cmd
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self.output_cb = callback
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cmd = os.path.expanduser(cmd)
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self.command = shlex.split(cmd)
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self.partial_output = b""
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self.cancelled = False
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self.return_code = None
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def _process_output(self, fd, events):
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if events & IOLoop.ERROR:
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return
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try:
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data = os.read(fd, 4096)
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except Exception:
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return
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data = self.partial_output + data
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lines = data.split(b'\n')
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self.partial_output = lines.pop()
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for line in lines:
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try:
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self.output_cb(line)
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except Exception:
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logging.exception("Error writing command output")
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def cancel(self):
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self.cancelled = True
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def get_return_code(self):
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return self.return_code
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async def run(self, timeout=2., verbose=True):
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self.return_code = fd = None
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self.partial_output = b""
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self.cancelled = False
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if timeout is None:
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# Never timeout
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timeout = 9999999999999999.
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if not timeout or self.output_cb is None:
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# Fire and forget commands cannot be verbose as we can't
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# clean up after the process terminates
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verbose = False
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try:
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proc = subprocess.Popen(
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self.command, stdout=subprocess.PIPE, stderr=subprocess.STDOUT)
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except Exception:
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logging.exception(
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f"shell_command: Command ({self.name}) failed")
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return False
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if verbose:
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fd = proc.stdout.fileno()
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self.io_loop.add_handler(
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fd, self._process_output, IOLoop.READ | IOLoop.ERROR)
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elif not timeout:
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# fire and forget, return from execution
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return True
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sleeptime = 0
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complete = False
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while sleeptime < timeout:
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await gen.sleep(.05)
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sleeptime += .05
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if proc.poll() is not None:
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complete = True
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break
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if self.cancelled:
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break
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if not complete:
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proc.terminate()
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if verbose:
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if self.partial_output:
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self.output_cb(self.partial_output)
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self.partial_output = b""
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self.io_loop.remove_handler(fd)
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self.return_code = proc.returncode
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success = self.return_code == 0 and complete
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if success:
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msg = f"Command ({self.name}) successfully finished"
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elif self.cancelled:
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msg = f"Command ({self.name}) cancelled"
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elif not complete:
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msg = f"Command ({self.name}) timed out"
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else:
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msg = f"Command ({self.name}) exited with return code" \
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f" {self.return_code}"
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logging.info(msg)
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return success
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async def run_with_response(self, timeout=2., retries=1):
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result = []
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def cb(data):
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data = data.strip()
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if data:
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result.append(data.decode())
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prev_cb = self.output_cb
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self.output_cb = cb
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while 1:
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ret = await self.run(timeout)
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if not ret or not result:
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retries -= 1
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if not retries:
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return None
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await gen.sleep(.5)
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result.clear()
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continue
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break
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self.output_cb = prev_cb
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return "\n".join(result)
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class ShellCommandFactory:
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def build_shell_command(self, cmd, callback=None):
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return ShellCommand(cmd, callback)
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def load_plugin(config):
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return ShellCommandFactory()
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