Arksine 34af0b4bfb shell_command: always log the result of a shell command
Use the return code to help determine if the command successfully finished.

Signed-off-by:  Eric Callahan <arksine.code@gmail.com>
2020-12-30 11:53:27 -05:00

123 lines
3.7 KiB
Python

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