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path: root/cloudinit/config/cc_bootcmd.py
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# Copyright (C) 2009-2011 Canonical Ltd.
# Copyright (C) 2012, 2013 Hewlett-Packard Development Company, L.P.
#
# Author: Scott Moser <scott.moser@canonical.com>
# Author: Juerg Haefliger <juerg.haefliger@hp.com>
# Author: Chad Smith <chad.smith@canonical.com>
#
# This file is part of cloud-init. See LICENSE file for license information.

"""Bootcmd: run arbitrary commands early in the boot process."""

import os
from textwrap import dedent

from cloudinit import subp, temp_utils, util
from cloudinit.config.schema import get_meta_doc
from cloudinit.settings import PER_ALWAYS

frequency = PER_ALWAYS

distros = ["all"]

meta = {
    "id": "cc_bootcmd",
    "name": "Bootcmd",
    "title": "Run arbitrary commands early in the boot process",
    "description": dedent(
        """\
        This module runs arbitrary commands very early in the boot process,
        only slightly after a boothook would run. This is very similar to a
        boothook, but more user friendly. The environment variable
        ``INSTANCE_ID`` will be set to the current instance id for all run
        commands. Commands can be specified either as lists or strings. For
        invocation details, see ``runcmd``.

        .. note::
            bootcmd should only be used for things that could not be done later
            in the boot process.

        .. note::

          when writing files, do not use /tmp dir as it races with
          systemd-tmpfiles-clean LP: #1707222. Use /run/somedir instead.
    """
    ),
    "distros": distros,
    "examples": [
        dedent(
            """\
        bootcmd:
            - echo 192.168.1.130 us.archive.ubuntu.com > /etc/hosts
            - [ cloud-init-per, once, mymkfs, mkfs, /dev/vdb ]
    """
        )
    ],
    "frequency": PER_ALWAYS,
}

__doc__ = get_meta_doc(meta)


def handle(name, cfg, cloud, log, _args):

    if "bootcmd" not in cfg:
        log.debug(
            "Skipping module named %s, no 'bootcmd' key in configuration", name
        )
        return

    with temp_utils.ExtendedTemporaryFile(suffix=".sh") as tmpf:
        try:
            content = util.shellify(cfg["bootcmd"])
            tmpf.write(util.encode_text(content))
            tmpf.flush()
        except Exception as e:
            util.logexc(log, "Failed to shellify bootcmd: %s", str(e))
            raise

        try:
            env = os.environ.copy()
            iid = cloud.get_instance_id()
            if iid:
                env["INSTANCE_ID"] = str(iid)
            cmd = ["/bin/sh", tmpf.name]
            subp.subp(cmd, env=env, capture=False)
        except Exception:
            util.logexc(log, "Failed to run bootcmd module %s", name)
            raise


# vi: ts=4 expandtab