# Copyright 2019, David Wilson
#
# Redistribution and use in source and binary forms, with or without
# modification, are permitted provided that the following conditions are met:
#
# 1. Redistributions of source code must retain the above copyright notice,
# this list of conditions and the following disclaimer.
#
# 2. Redistributions in binary form must reproduce the above copyright notice,
# this list of conditions and the following disclaimer in the documentation
# and/or other materials provided with the distribution.
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# 3. Neither the name of the copyright holder nor the names of its contributors
# may be used to endorse or promote products derived from this software without
# specific prior written permission.
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# THIS SOFTWARE IS PROVIDED BY THE COPYRIGHT HOLDERS AND CONTRIBUTORS "AS IS"
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# IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE
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# POSSIBILITY OF SUCH DAMAGE.

# !mitogen: minify_safe

import mitogen.parent


class Options(mitogen.parent.Options):
    container = None
    lxc_attach_path = 'lxc-attach'

    def __init__(self, container, lxc_attach_path=None, **kwargs):
        super(Options, self).__init__(**kwargs)
        self.container = container
        if lxc_attach_path:
            self.lxc_attach_path = lxc_attach_path


class Connection(mitogen.parent.Connection):
    options_class = Options

    child_is_immediate_subprocess = False
    create_child_args = {
        # If lxc-attach finds any of stdin, stdout, stderr connected to a TTY,
        # to prevent input injection it creates a proxy pty, forcing all IO to
        # be buffered in <4KiB chunks. So ensure stderr is also routed to the
        # socketpair.
        'merge_stdio': True
    }

    eof_error_hint = (
        'Note: many versions of LXC do not report program execution failure '
        'meaningfully. Please check the host logs (/var/log) for more '
        'information.'
    )

    def _get_name(self):
        return u'lxc.' + self.options.container

    def get_boot_command(self):
        bits = [
            self.options.lxc_attach_path,
            '--clear-env',
            '--name', self.options.container,
            '--',
        ]
        return bits + super(Connection, self).get_boot_command()