Running external commands with irclib

irclib_external_command_bot.py

# -*- coding: utf-8 -*-
import subprocess

import irclib


class ExternalCommand(irclib.Connection):
    """Represents an external command invocation made via irclib.

    Sample usage
    ------------
    class Bot(ircbot.SingleServerIRCBot):
        def on_welcome(self, connection, event):
            ExternalCommand(self.ircobj, ['/bin/ls', '-a'], timeout=10)

        def on_external_command_exit(self, connection, event):
            self.connection.privmsg(self.chans,
                'Exit status: %s; Output: %s' % (exit_status, command_output))

        def on_external_command_timeout(self, connection, event):
            self.connection.privmsg(self.chans, 'Command timed out.')

    """

    def __init__(self, irclibobj, command, shell=False, timeout=None):
        """
        Constructor.

        Parameters
        ----------
        irclibobj: irclib.IRC object.
        command: command line as a list, e.g. ['/bin/ls', '-l'].
        shell: passed to subprocess.Popen constructor.
        timeout: if set, kill command after this many seconds.
        """
        self.buffer = ''
        self.irclibobj = irclibobj
        self.irclibobj.connections.append(self)
        self.proc = subprocess.Popen(
            command, stdout=subprocess.PIPE, shell=shell)
        if timeout is not None:
            self.execute_delayed(timeout, self.process_timeout)

    def _get_socket(self):
        """Called by IRC.process_once() to get the file object to poll."""
        return self.proc.stdout

    def process_data(self):
        """Read data from processes's stdout. Check if process terminated.
        If it has, fire `external_command_exit` event."""
        status = self.proc.poll()
        self.buffer += self.proc.stdout.read()
        if status is not None:
            event = irclib.Event('external_command_exit', self.proc, '',
                                 [status, self.buffer])
            self.irclibobj._handle_event(self, event)
            self.irclibobj._remove_connection(self)

    def process_timeout(self):
        """If the external command has not yet terminated, kill it and fire
        `external_command_timeout` event."""
        if self.proc.poll() is not None:
            # No need to enforce timeout b/c process has already terminated.
            return
        self.proc.kill()
        event = irclib.Event('external_command_timeout', self.proc, '')
        self.irclibobj._handle_event(self, event)
        self.irclibobj._remove_connection(self)

    def disconnect(self):
        """Kill the external command's process and disenroll its stdout from
        irclib's select()."""
        self.proc.kill()
        self.irclibobj._remove_connection(self)