community.general/lib/ansible/plugins/action/pause.py

# Copyright 2012, Tim Bielawa <tbielawa@redhat.com>
#
# This file is part of Ansible
#
# Ansible is free software: you can redistribute it and/or modify
# it under the terms of the GNU General Public License as published by
# the Free Software Foundation, either version 3 of the License, or
# (at your option) any later version.
#
# Ansible is distributed in the hope that it will be useful,
# but WITHOUT ANY WARRANTY; without even the implied warranty of
# MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
# GNU General Public License for more details.
#
# You should have received a copy of the GNU General Public License
# along with Ansible.  If not, see <http://www.gnu.org/licenses/>.
from __future__ import (absolute_import, division, print_function)
__metaclass__ = type

import datetime
import signal
import sys
import termios
import time
import tty

from ansible.errors import *
from ansible.plugins.action import ActionBase

class AnsibleTimeoutExceeded(Exception):
    pass

def timeout_handler(signum, frame):
    raise AnsibleTimeoutExceeded

class ActionModule(ActionBase):
    ''' pauses execution for a length or time, or until input is received '''

    PAUSE_TYPES = ['seconds', 'minutes', 'prompt', '']
    BYPASS_HOST_LOOP = True

    def run(self, tmp=None, task_vars=dict()):
        ''' run the pause action module '''

        duration_unit = 'minutes'
        prompt = None
        seconds = None
        result = dict(
            changed = False,
            rc      = 0,
            stderr  = '',
            stdout  = '',
            start   = None,
            stop    = None,
            delta   = None,
        )

        # Is 'args' empty, then this is the default prompted pause
        if self._task.args is None or len(self._task.args.keys()) == 0:
            pause_type = 'prompt'
            prompt = "[%s]\nPress enter to continue:\n" % self._task.get_name().strip()

        # Are 'minutes' or 'seconds' keys that exist in 'args'?
        elif 'minutes' in self._task.args or 'seconds' in self._task.args:
            try:
                if 'minutes' in self._task.args:
                    pause_type = 'minutes'
                    # The time() command operates in seconds so we need to
                    # recalculate for minutes=X values.
                    seconds = int(self._task.args['minutes']) * 60
                else:
                    pause_type = 'seconds'
                    seconds = int(self._task.args['seconds'])
                    duration_unit = 'seconds'

            except ValueError as e:
                return dict(failed=True, msg="non-integer value given for prompt duration:\n%s" % str(e))

        # Is 'prompt' a key in 'args'?
        elif 'prompt' in self._task.args:
            pause_type = 'prompt'
            prompt = "[%s]\n%s:\n" % (self._task.get_name().strip(), self._task.args['prompt'])

        else:
            # I have no idea what you're trying to do. But it's so wrong.
            return dict(failed=True, msg="invalid pause type given. must be one of: %s" % ", ".join(self.PAUSE_TYPES))

        ########################################################################
        # Begin the hard work!

        start = time.time()
        result['start'] = str(datetime.datetime.now())

        try:
            if seconds is not None:
                # setup the alarm handler
                signal.signal(signal.SIGALRM, timeout_handler)
                signal.alarm(seconds)
                # show the prompt
                print("Pausing for %d seconds" % seconds)
                print("(ctrl+C then 'C' = continue early, ctrl+C then 'A' = abort)\r"),
            else:
                print("(press enter to continue, ctrl+C to abort)")

            # save the attributes on the existing (duped) stdin so
            # that we can restore them later after we set raw mode
            fd = self._connection._new_stdin.fileno()
            old_settings = termios.tcgetattr(fd)
            tty.setraw(fd)

            # flush the buffer to make sure no previous key presses
            # are read in below 
            termios.tcflush(self._connection._new_stdin, termios.TCIFLUSH)

            # read key presses and act accordingly
            while True:
                key_pressed = self._connection._new_stdin.read(1)
                if pause_type in ('minutes', 'seconds'):
                    if key_pressed == '\x03':
                        key_pressed = self._connection._new_stdin.read(1)
                        if key_pressed == 'a':
                            raise KeyboardInterrupt
                        elif key_pressed == 'c':
                            break
                else:
                    if key_pressed == '\x03':
                        raise KeyboardInterrupt
                    elif key_pressed == '\r':
                        break
        except KeyboardInterrupt:
            # cancel the previously set alarm signal
            if seconds is not None:
                signal.alarm(0)
            raise AnsibleError('user requested abort!')
        except AnsibleTimeoutExceeded:
            # this is the exception we expect when the alarm signal
            # fires, so we simply ignore it to move into the cleanup
            pass
        finally:
            # cleanup and save some information
            # restore the old settings for the duped stdin fd
            termios.tcsetattr(fd, termios.TCSADRAIN, old_settings)

            duration = time.time() - start
            result['stop'] = str(datetime.datetime.now())
            result['delta'] = int(duration)

            if duration_unit == 'minutes':
                duration = round(duration / 60.0, 2)
            else:
                duration = round(duration, 2)

            result['stdout'] = "Paused for %s %s" % (duration, duration_unit)

        return result