platypush/platypush/plugins/shell/__init__.py

132 lines
4.2 KiB
Python

from base64 import b64encode
import json
import subprocess
import threading
import time
from typing import Callable, Optional
from uuid import uuid1
from platypush.common.cmd_stream import redis_topic
from platypush.plugins import Plugin, action
from platypush.utils import get_redis
class ShellPlugin(Plugin):
"""
Plugin to run shell commands.
"""
def __init__(self, *args, **kwargs):
super().__init__(*args, **kwargs)
def _exec(self, func: Callable, cmd: str, ignore_errors: bool = False):
try:
return func(cmd)
except subprocess.CalledProcessError as e:
if ignore_errors:
self.logger.warning(
'Command %s failed with error: %s', cmd, e.output.decode()
)
return None
raise RuntimeError(e.output.decode()) from e
def _exec_simple(self, cmd: str):
return subprocess.check_output(
cmd, stderr=subprocess.STDOUT, shell=True
).decode()
@staticmethod
def _send_ws_output(cmd_id: str, buf: Optional[bytes]):
get_redis().publish(
redis_topic,
json.dumps(
{
'id': cmd_id,
'output': (b64encode(buf).decode() if buf is not None else None),
}
),
)
def _exec_ws_thread(self, cmd: str, cmd_id: str):
try:
with subprocess.Popen(
cmd,
shell=True,
stdout=subprocess.PIPE,
) as proc:
first_loop = True
while proc.poll() is None and proc.stdout and proc.stdout.readable():
buf = b''
bufsize = 1024
while len(buf) < bufsize:
ch = proc.stdout.read(1)
if not ch:
break
buf += ch
if ch in (b'\r', b'\n'):
break
if first_loop:
first_loop = False
# An artificial delay to let the client connect to the websocket,
# otherwise the first few lines of output might be lost.
time.sleep(2)
self._send_ws_output(cmd_id, buf)
finally:
self._send_ws_output(cmd_id, None)
def _exec_ws(self, cmd: str):
cmd_id = str(uuid1())
threading.Thread(target=self._exec_ws_thread, args=(cmd, cmd_id)).start()
return {'ws_path': f'/ws/shell?id={cmd_id}'}
@action
def exec(
self,
cmd: str,
background: bool = False,
ws: bool = False,
ignore_errors: bool = False,
):
"""
Run a command.
:param cmd: Command to execute
:param background: If set to True, execute the process in the
background, otherwise wait for the process termination and return
its output (default: False).
:param ignore_errors: If set, then any errors in the command execution
will be ignored. Otherwise a RuntimeError will be thrown (default
value: False)
:param ws: If set to True then the output of the command will be
sent asynchronously over a websocket channel (default: False).
In this case, the method will return a response in the format:
.. code-block:: json
{
"ws_path": "/ws/shell?id=<cmd_id>"
}
Where ``ws_path`` is the websocket path where the output of the
command will be sent. The websocket will be closed when the command
terminates.
:returns: A response object where the ``output`` field will contain the
command output as a string, and the ``errors`` field will contain
whatever was sent to stderr.
"""
if background:
subprocess.Popen(cmd, shell=True)
return None
func = self._exec_ws if ws else self._exec_simple
return self._exec(func, cmd, ignore_errors=ignore_errors)
# vim:sw=4:ts=4:et: