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✏️ Editing: cc_apt_configure.py

# Copyright (C) 2009-2010 Canonical Ltd.
# Copyright (C) 2012 Hewlett-Packard Development Company, L.P.
#
# Author: Scott Moser <scott.moser@canonical.com>
# Author: Juerg Haefliger <juerg.haefliger@hp.com>
#
# This file is part of cloud-init. See LICENSE file for license information.

"""Apt Configure: Configure apt for the user."""

import glob
import logging
import os
import pathlib
import re
import shutil
import signal
from textwrap import dedent, indent
from typing import Dict, Iterable, List, Mapping

from cloudinit import features, gpg, subp, templater, util
from cloudinit.cloud import Cloud
from cloudinit.config import Config
from cloudinit.config.schema import MetaSchema, get_meta_doc
from cloudinit.settings import PER_INSTANCE

LOG = logging.getLogger(__name__)

# this will match 'XXX:YYY' (ie, 'cloud-archive:foo' or 'ppa:bar')
ADD_APT_REPO_MATCH = r"^[\w-]+:\w"

APT_LOCAL_KEYS = "/etc/apt/trusted.gpg"
APT_TRUSTED_GPG_DIR = "/etc/apt/trusted.gpg.d/"
CLOUD_INIT_GPG_DIR = "/etc/apt/cloud-init.gpg.d/"
DISABLE_SUITES_REDACT_PREFIX = "# cloud-init disable_suites redacted: "

frequency = PER_INSTANCE
distros = ["ubuntu", "debian"]

PACKAGE_DEPENDENCY_BY_COMMAND: Mapping[str, str] = {
    "add-apt-repository": "software-properties-common",
    "gpg": "gnupg",
}

meta: MetaSchema = {
    "id": "cc_apt_configure",
    "name": "Apt Configure",
    "title": "Configure apt for the user",
    "description": dedent(
        """\
        This module handles both configuration of apt options and adding
        source lists.  There are configuration options such as
        ``apt_get_wrapper`` and ``apt_get_command`` that control how
        cloud-init invokes apt-get. These configuration options are
        handled on a per-distro basis, so consult documentation for
        cloud-init's distro support for instructions on using
        these config options.

By default, cloud-init will generate default
        apt sources information in deb822 format at
        :file:`/etc/apt/sources.list.d/<distro>.sources`. When the value
        of `sources_list` does not appear to be deb822 format, or stable
        distribution releases disable deb822 format,
        :file:`/etc/apt/sources.list` will be written instead.

.. note::
            To ensure that apt configuration is valid yaml, any strings
            containing special characters, especially ``:`` should be quoted.

.. note::
            For more information about apt configuration, see the
            ``Additional apt configuration`` example."""
    ),
    "distros": distros,
    "examples": [
        dedent(
            """\
        apt:
          preserve_sources_list: false
          disable_suites:
            - $RELEASE-updates
            - backports
            - $RELEASE
            - mysuite
          primary:
            - arches:
                - amd64
                - i386
                - default
              uri: 'http://us.archive.ubuntu.com/ubuntu'
              search:
                - 'http://cool.but-sometimes-unreachable.com/ubuntu'
                - 'http://us.archive.ubuntu.com/ubuntu'
              search_dns: false
            - arches:
                - s390x
                - arm64
              uri: 'http://archive-to-use-for-arm64.example.com/ubuntu'

security:
            - arches:
                - default
              search_dns: true
          sources_list: |
              deb $MIRROR $RELEASE main restricted
              deb-src $MIRROR $RELEASE main restricted
              deb $PRIMARY $RELEASE universe restricted
              deb $SECURITY $RELEASE-security multiverse
          debconf_selections:
              set1: the-package the-package/some-flag boolean true
          conf: |
              APT {
                  Get {
                      Assume-Yes 'true';
                      Fix-Broken 'true';
                  }
              }
          proxy: 'http://[[user][:pass]@]host[:port]/'
          http_proxy: 'http://[[user][:pass]@]host[:port]/'
          ftp_proxy: 'ftp://[[user][:pass]@]host[:port]/'
          https_proxy: 'https://[[user][:pass]@]host[:port]/'
          sources:
              source1:
                  keyid: 'keyid'
                  keyserver: 'keyserverurl'
                  source: 'deb [signed-by=$KEY_FILE] http://<url>/ bionic main'
              source2:
                  source: 'ppa:<ppa-name>'
              source3:
                  source: 'deb $MIRROR $RELEASE multiverse'
                  key: |
                      ------BEGIN PGP PUBLIC KEY BLOCK-------
                      <key data>
                      ------END PGP PUBLIC KEY BLOCK-------
              source4:
                  source: 'deb $MIRROR $RELEASE multiverse'
                  append: false
                  key: |
                      ------BEGIN PGP PUBLIC KEY BLOCK-------
                      <key data>
                      ------END PGP PUBLIC KEY BLOCK-------"""
        ),
        dedent(
            """\
        # cloud-init version 23.4 will generate a deb822 formatted sources
        # file at /etc/apt/sources.list.d/<distro>.sources instead of
        # /etc/apt/sources.list when  `sources_list` content is deb822
        # format.
        apt:
            sources_list: |
              Types: deb
              URIs: http://archive.ubuntu.com/ubuntu/
              Suites: $RELEASE
              Components: main
            """
        ),
    ],
    "frequency": frequency,
    "activate_by_schema_keys": [],
}

__doc__ = get_meta_doc(meta)

# place where apt stores cached repository data
APT_LISTS = "/var/lib/apt/lists"

# Files to store proxy information
APT_CONFIG_FN = "/etc/apt/apt.conf.d/94cloud-init-config"
APT_PROXY_FN = "/etc/apt/apt.conf.d/90cloud-init-aptproxy"

# Default keyserver to use
DEFAULT_KEYSERVER = "keyserver.ubuntu.com"

# Default archive mirrors
PRIMARY_ARCH_MIRRORS = {
    "PRIMARY": "http://archive.ubuntu.com/ubuntu/",
    "SECURITY": "http://security.ubuntu.com/ubuntu/",
}
PORTS_MIRRORS = {
    "PRIMARY": "http://ports.ubuntu.com/ubuntu-ports",
    "SECURITY": "http://ports.ubuntu.com/ubuntu-ports",
}
PRIMARY_ARCHES = ["amd64", "i386"]
PORTS_ARCHES = ["s390x", "arm64", "armhf", "powerpc", "ppc64el", "riscv64"]

def get_default_mirrors(arch=None, target=None):
    """returns the default mirrors for the target. These depend on the
    architecture, for more see:
    https://wiki.ubuntu.com/UbuntuDevelopment/PackageArchive#Ports"""
    if arch is None:
        arch = util.get_dpkg_architecture(target)
    if arch in PRIMARY_ARCHES:
        return PRIMARY_ARCH_MIRRORS.copy()
    if arch in PORTS_ARCHES:
        return PORTS_MIRRORS.copy()
    raise ValueError("No default mirror known for arch %s" % arch)

def handle(name: str, cfg: Config, cloud: Cloud, args: list) -> None:
    """process the config for apt_config. This can be called from
    curthooks if a global apt config was provided or via the "apt"
    standalone command."""
    # keeping code close to curtin codebase via entry handler
    target = None
    # feed back converted config, but only work on the subset under 'apt'
    cfg = convert_to_v3_apt_format(cfg)
    apt_cfg = cfg.get("apt", {})

if not isinstance(apt_cfg, dict):
        raise ValueError(
            "Expected dictionary for 'apt' config, found {config_type}".format(
                config_type=type(apt_cfg)
            )
        )

apply_debconf_selections(apt_cfg, target)
    apply_apt(apt_cfg, cloud, target)

def _should_configure_on_empty_apt():
    # if no config was provided, should apt configuration be done?
    if util.system_is_snappy():
        return False, "system is snappy."
    if not (subp.which("apt-get") or subp.which("apt")):
        return False, "no apt commands."
    return True, "Apt is available."

def apply_apt(cfg, cloud, target):
    # cfg is the 'apt' top level dictionary already in 'v3' format.
    if not cfg:
        should_config, msg = _should_configure_on_empty_apt()
        if not should_config:
            LOG.debug("Nothing to do: No apt config and %s", msg)
            return

LOG.debug("handling apt config: %s", cfg)

release = util.lsb_release(target=target)["codename"]
    arch = util.get_dpkg_architecture(target)
    mirrors = find_apt_mirror_info(cfg, cloud, arch=arch)
    LOG.debug("Apt Mirror info: %s", mirrors)

matcher = None
    matchcfg = cfg.get("add_apt_repo_match", ADD_APT_REPO_MATCH)
    if matchcfg:
        matcher = re.compile(matchcfg).search
    _ensure_dependencies(cfg, matcher, cloud)

if util.is_false(cfg.get("preserve_sources_list", False)):
        add_mirror_keys(cfg, cloud, target)
        generate_sources_list(cfg, release, mirrors, cloud)
        rename_apt_lists(mirrors, target, arch)

try:
        apply_apt_config(cfg, APT_PROXY_FN, APT_CONFIG_FN)
    except (IOError, OSError):
        LOG.exception("Failed to apply proxy or apt config info:")

# Process 'apt_source -> sources {dict}'
    if "sources" in cfg:
        params = mirrors
        params["RELEASE"] = release
        params["MIRROR"] = mirrors["MIRROR"]

add_apt_sources(
            cfg["sources"],
            cloud,
            target=target,
            template_params=params,
            aa_repo_match=matcher,
        )
    # GH: 4344 - stop gpg-agent/dirmgr daemons spawned by gpg key imports.
    # Daemons spawned by cloud-config.service on systemd v253 report (running)
    gpg_process_out, _err = subp.subp(
        ["ps", "-o", "ppid,pid", "-C", "dirmngr", "-C", "gpg-agent"],
        target=target,
        capture=True,
        rcs=[0, 1],
    )
    gpg_pids = re.findall(r"(?P<ppid>\d+)\s+(?P<pid>\d+)", gpg_process_out)
    root_gpg_pids = [int(pid[1]) for pid in gpg_pids if pid[0] == "1"]
    if root_gpg_pids:
        LOG.debug("Killing gpg-agent and dirmngr pids: %s", root_gpg_pids)
    for gpg_pid in root_gpg_pids:
        os.kill(gpg_pid, signal.SIGKILL)

def debconf_set_selections(selections, target=None):
    if not selections.endswith(b"\n"):
        selections += b"\n"
    subp.subp(
        ["debconf-set-selections"],
        data=selections,
        target=target,
        capture=True,
    )

def dpkg_reconfigure(packages, target=None):
    # For any packages that are already installed, but have preseed data
    # we populate the debconf database, but the filesystem configuration
    # would be preferred on a subsequent dpkg-reconfigure.
    # so, what we have to do is "know" information about certain packages
    # to unconfigure them.
    unhandled = []
    to_config = []
    for pkg in packages:
        if pkg in CONFIG_CLEANERS:
            LOG.debug("unconfiguring %s", pkg)
            CONFIG_CLEANERS[pkg](target)
            to_config.append(pkg)
        else:
            unhandled.append(pkg)

if len(unhandled):
        LOG.warning(
            "The following packages were installed and preseeded, "
            "but cannot be unconfigured: %s",
            unhandled,
        )

if len(to_config):
        subp.subp(
            ["dpkg-reconfigure", "--frontend=noninteractive"]
            + list(to_config),
            data=None,
            target=target,
            capture=True,
        )

def apply_debconf_selections(cfg, target=None):
    """apply_debconf_selections - push content to debconf"""
    # debconf_selections:
    #  set1: |
    #   cloud-init cloud-init/datasources multiselect MAAS
    #  set2: pkg pkg/value string bar
    selsets = cfg.get("debconf_selections")
    if not selsets:
        LOG.debug("debconf_selections was not set in config")
        return

selections = "\n".join([selsets[key] for key in sorted(selsets.keys())])
    debconf_set_selections(selections.encode(), target=target)

# get a complete list of packages listed in input
    pkgs_cfgd = set()
    for _key, content in selsets.items():
        for line in content.splitlines():
            if line.startswith("#"):
                continue
            pkg = re.sub(r"[:\s].*", "", line)
            pkgs_cfgd.add(pkg)

pkgs_installed = util.get_installed_packages(target)

LOG.debug("pkgs_cfgd: %s", pkgs_cfgd)
    need_reconfig = pkgs_cfgd.intersection(pkgs_installed)

if len(need_reconfig) == 0:
        LOG.debug("no need for reconfig")
        return

dpkg_reconfigure(need_reconfig, target=target)

def clean_cloud_init(target):
    """clean out any local cloud-init config"""
    flist = glob.glob(
        subp.target_path(target, "/etc/cloud/cloud.cfg.d/*dpkg*")
    )

LOG.debug("cleaning cloud-init config from: %s", flist)
    for dpkg_cfg in flist:
        os.unlink(dpkg_cfg)

def mirrorurl_to_apt_fileprefix(mirror):
    """mirrorurl_to_apt_fileprefix
    Convert a mirror url to the file prefix used by apt on disk to
    store cache information for that mirror.
    To do so do:
    - take off ???://
    - drop tailing /
    - convert in string / to _"""
    string = mirror
    if string.endswith("/"):
        string = string[0:-1]
    pos = string.find("://")
    if pos >= 0:
        string = string[pos + 3 :]
    string = string.replace("/", "_")
    return string

def rename_apt_lists(new_mirrors, target, arch):
    """rename_apt_lists - rename apt lists to preserve old cache data"""
    default_mirrors = get_default_mirrors(arch)

pre = subp.target_path(target, APT_LISTS)
    for name, omirror in default_mirrors.items():
        nmirror = new_mirrors.get(name)
        if not nmirror:
            continue

oprefix = pre + os.path.sep + mirrorurl_to_apt_fileprefix(omirror)
        nprefix = pre + os.path.sep + mirrorurl_to_apt_fileprefix(nmirror)
        if oprefix == nprefix:
            continue
        olen = len(oprefix)
        for filename in glob.glob("%s_*" % oprefix):
            newname = "%s%s" % (nprefix, filename[olen:])
            LOG.debug("Renaming apt list %s to %s", filename, newname)
            try:
                os.rename(filename, newname)
            except OSError:
                # since this is a best effort task, warn with but don't fail
                LOG.warning("Failed to rename apt list:", exc_info=True)

def map_known_suites(suite):
    """there are a few default names which will be auto-extended.
    This comes at the inability to use those names literally as suites,
    but on the other hand increases readability of the cfg quite a lot"""
    mapping = {
        "updates": "$RELEASE-updates",
        "backports": "$RELEASE-backports",
        "security": "$RELEASE-security",
        "proposed": "$RELEASE-proposed",
        "release": "$RELEASE",
    }
    try:
        retsuite = mapping[suite]
    except KeyError:
        retsuite = suite
    return retsuite

def disable_deb822_section_without_suites(deb822_entry: str) -> str:
    """If no active Suites, disable this deb822 source."""
    if not re.findall(r"\nSuites:[ \t]+([\w-]+)", deb822_entry):
        # No Suites remaining in this entry, disable full entry
        # Reconstitute commented Suites line to original as we disable entry
        deb822_entry = re.sub(r"\nSuites:.*", "", deb822_entry)
        deb822_entry = re.sub(
            rf"{DISABLE_SUITES_REDACT_PREFIX}", "", deb822_entry
        )
        return (
            "## Entry disabled by cloud-init, due to disable_suites\n"
            + indent(deb822_entry, "# disabled by cloud-init: ")
        )
    return deb822_entry

def disable_suites_deb822(disabled, src, release) -> str:
    """reads the deb822 format config and comment disabled suites"""
    new_src = []
    disabled_suite_names = [
        templater.render_string(map_known_suites(suite), {"RELEASE": release})
        for suite in disabled
    ]
    LOG.debug("Disabling suites %s as %s", disabled, disabled_suite_names)
    new_deb822_entry = ""
    for line in src.splitlines():
        if line.startswith("#"):
            if new_deb822_entry:
                new_deb822_entry += f"{line}\n"
            else:
                new_src.append(line)
            continue
        if not line or line.isspace():
            # Validate/disable deb822 entry upon whitespace
            if new_deb822_entry:
                new_src.append(
                    disable_deb822_section_without_suites(new_deb822_entry)
                )
                new_deb822_entry = ""
            new_src.append(line)
            continue
        new_line = line
        if not line.startswith("Suites:"):
            new_deb822_entry += line + "\n"
            continue
        # redact all disabled suite names
        if disabled_suite_names:
            # Redact any matching Suites from line
            orig_suites = line.split()[1:]
            new_suites = [
                suite
                for suite in orig_suites
                if suite not in disabled_suite_names
            ]
            if new_suites != orig_suites:
                new_deb822_entry += f"{DISABLE_SUITES_REDACT_PREFIX}{line}\n"
                new_line = f"Suites: {' '.join(new_suites)}"
        new_deb822_entry += new_line + "\n"
    if new_deb822_entry:
        new_src.append(disable_deb822_section_without_suites(new_deb822_entry))
    return "\n".join(new_src)

def disable_suites(disabled, src, release) -> str:
    """reads the config for suites to be disabled and removes those
    from the template"""
    if not disabled:
        return src

retsrc = src
    if is_deb822_sources_format(src):
        return disable_suites_deb822(disabled, src, release)
    for suite in disabled:
        suite = map_known_suites(suite)
        releasesuite = templater.render_string(suite, {"RELEASE": release})
        LOG.debug("Disabling suite %s as %s", suite, releasesuite)

newsrc = ""
        for line in retsrc.splitlines(True):
            if line.startswith("#"):
                newsrc += line
                continue

# sources.list allow options in cols[1] which can have spaces
            # so the actual suite can be [2] or later. example:
            # deb [ arch=amd64,armel k=v ] http://example.com/debian
            cols = line.split()
            if len(cols) > 1:
                pcol = 2
                if cols[1].startswith("["):
                    for col in cols[1:]:
                        pcol += 1
                        if col.endswith("]"):
                            break

if cols[pcol] == releasesuite:
                    line = "# suite disabled by cloud-init: %s" % line
            newsrc += line
        retsrc = newsrc

return retsrc

def add_mirror_keys(cfg, cloud, target):
    """Adds any keys included in the primary/security mirror clauses"""
    for key in ("primary", "security"):
        for mirror in cfg.get(key, []):
            add_apt_key(mirror, cloud, target, file_name=key)

def is_deb822_sources_format(apt_src_content: str) -> bool:
    """Simple check for deb822 format for apt source content

Only validates that minimal required keys are present in the file, which
    indicates we are likely deb822 format.

Doesn't handle if multiple sections all contain deb822 keys.

Return True if content looks like it is deb822 formatted APT source.
    """
    # TODO(At jammy EOL: use aptsources.sourceslist.Deb822SourceEntry.invalid)
    if re.findall(r"^(deb |deb-src )", apt_src_content, re.M):
        return False
    if re.findall(
        r"^(Types: |Suites: |Components: |URIs: )", apt_src_content, re.M
    ):
        return True
    # Did not match any required deb822 format keys
    LOG.warning(
        "apt.sources_list value does not match either deb822 source keys or"
        " deb/deb-src list keys. Assuming APT deb/deb-src list format."
    )
    return False

DEFAULT_APT_CFG = {
    "Dir::Etc": "etc/apt",
    "Dir::Etc::sourcelist": "sources.list",
    "Dir::Etc::sourceparts": "sources.list.d",
}

APT_CFG_RE = (
    r"(Dir::Etc|Dir::Etc::sourceparts|Dir::Etc::sourcelist) \"([^\"]+)"
)

def get_apt_cfg() -> Dict[str, str]:
    """Return a dict of applicable apt configuration or defaults.

Prefer python apt_pkg if present.
    Fallback to apt-config dump command if present out output parsed
    Fallback to DEFAULT_APT_CFG if apt-config commmand absent or
    output unparsable.
    """
    try:
        # python3-apt package is only a Recommends: not a strict Requires:
        # in debian/control. Prefer the apt_pkg python module for APT
        # interaction due to 7 ms performance improvement above subp.
        # Given that debian/buntu images may not contain python3-apt
        # fallback to subp if the image lacks this dependency.
        import apt_pkg  # type: ignore

apt_pkg.init_config()
        etc = apt_pkg.config.get("Dir::Etc", DEFAULT_APT_CFG["Dir::Etc"])
        sourcelist = apt_pkg.config.get(
            "Dir::Etc::sourcelist", DEFAULT_APT_CFG["Dir::Etc::sourcelist"]
        )
        sourceparts = apt_pkg.config.get(
            "Dir::Etc::sourceparts", DEFAULT_APT_CFG["Dir::Etc::sourceparts"]
        )
    except ImportError:

try:
            apt_dump, _ = subp.subp(["apt-config", "dump"])
        except subp.ProcessExecutionError:
            # No apt-config, return defaults
            etc = DEFAULT_APT_CFG["Dir::Etc"]
            sourcelist = DEFAULT_APT_CFG["Dir::Etc::sourcelist"]
            sourceparts = DEFAULT_APT_CFG["Dir::Etc::sourceparts"]
            return {
                "sourcelist": f"/{etc}/{sourcelist}",
                "sourceparts": f"/{etc}/{sourceparts}/",
            }
        matched_cfg = re.findall(APT_CFG_RE, apt_dump)
        apt_cmd_config = dict(matched_cfg)
        etc = apt_cmd_config.get("Dir::Etc", DEFAULT_APT_CFG["Dir::Etc"])
        sourcelist = apt_cmd_config.get(
            "Dir::Etc::sourcelist", DEFAULT_APT_CFG["Dir::Etc::sourcelist"]
        )
        sourceparts = apt_cmd_config.get(
            "Dir::Etc::sourceparts", DEFAULT_APT_CFG["Dir::Etc::sourceparts"]
        )
    return {
        "sourcelist": f"/{etc}/{sourcelist}",
        "sourceparts": f"/{etc}/{sourceparts}/",
    }

def generate_sources_list(cfg, release, mirrors, cloud):
    """generate_sources_list
    create a source.list file based on a custom or default template
    by replacing mirrors and release in the template"""
    apt_cfg = get_apt_cfg()
    apt_sources_list = apt_cfg["sourcelist"]
    apt_sources_deb822 = f"{apt_cfg['sourceparts']}{cloud.distro.name}.sources"
    if features.APT_DEB822_SOURCE_LIST_FILE:
        aptsrc_file = apt_sources_deb822
    else:
        aptsrc_file = apt_sources_list

params = {"RELEASE": release, "codename": release}
    for k in mirrors:
        params[k] = mirrors[k]
        params[k.lower()] = mirrors[k]

tmpl = cfg.get("sources_list", None)
    if not tmpl:
        LOG.info("No custom template provided, fall back to builtin")
        tmpl_fmt = ".deb822" if features.APT_DEB822_SOURCE_LIST_FILE else ""
        template_fn = cloud.get_template_filename(
            f"sources.list.{cloud.distro.name}{tmpl_fmt}"
        )
        if not template_fn:
            template_fn = cloud.get_template_filename("sources.list")
        if not template_fn:
            LOG.warning("No template found, not rendering %s", aptsrc_file)
            return
        tmpl = util.load_file(template_fn)

rendered = templater.render_string(tmpl, params)
    if tmpl:
        if is_deb822_sources_format(rendered):
            if aptsrc_file == apt_sources_list:
                LOG.debug(
                    "Provided 'sources_list' user-data is deb822 format,"
                    " writing to %s",
                    apt_sources_deb822,
                )
                aptsrc_file = apt_sources_deb822
        else:
            LOG.debug(
                "Provided 'sources_list' user-data is not deb822 format,"
                " fallback to %s",
                apt_sources_list,
            )
            aptsrc_file = apt_sources_list
    disabled = disable_suites(cfg.get("disable_suites"), rendered, release)
    util.write_file(aptsrc_file, disabled, mode=0o644)

def add_apt_key_raw(key, file_name, hardened=False, target=None):
    """
    actual adding of a key as defined in key argument
    to the system
    """
    LOG.debug("Adding key:\n'%s'", key)
    try:
        name = pathlib.Path(file_name).stem
        return apt_key("add", output_file=name, data=key, hardened=hardened)
    except subp.ProcessExecutionError:
        LOG.exception("failed to add apt GPG Key to apt keyring")
        raise

def _ensure_dependencies(cfg, aa_repo_match, cloud):
    """Install missing package dependencies based on apt_sources config.

Inspect the cloud config user-data provided. When user-data indicates
    conditions where add_apt_key or add-apt-repository will be called,
    ensure the required command dependencies are present installed.

Perform this inspection upfront because it is very expensive to call
    distro.install_packages due to a preliminary 'apt update' called before
    package installation.
    """
    missing_packages: List[str] = []
    required_cmds: Iterable[str] = set()
    if util.is_false(cfg.get("preserve_sources_list", False)):
        for mirror_key in ("primary", "security"):
            if cfg.get(mirror_key):
                # Include gpg when mirror_key non-empty list and any item
                # defines key or keyid.
                for mirror_item in cfg[mirror_key]:
                    if {"key", "keyid"}.intersection(mirror_item):
                        required_cmds.add("gpg")
    apt_sources_dict = cfg.get("sources", {})
    for ent in apt_sources_dict.values():
        if {"key", "keyid"}.intersection(ent):
            required_cmds.add("gpg")
        if aa_repo_match(ent.get("source", "")):
            required_cmds.add("add-apt-repository")
    for command in required_cmds:
        if not shutil.which(command):
            missing_packages.append(PACKAGE_DEPENDENCY_BY_COMMAND[command])
    if missing_packages:
        cloud.distro.install_packages(sorted(missing_packages))

def add_apt_key(ent, cloud, target=None, hardened=False, file_name=None):
    """
    Add key to the system as defined in ent (if any).
    Supports raw keys or keyid's
    The latter will as a first step fetched to get the raw key
    """
    if "keyid" in ent and "key" not in ent:
        keyserver = DEFAULT_KEYSERVER
        if "keyserver" in ent:
            keyserver = ent["keyserver"]

ent["key"] = gpg.getkeybyid(ent["keyid"], keyserver)

if "key" in ent:
        return add_apt_key_raw(
            ent["key"], file_name or ent["filename"], hardened=hardened
        )

def update_packages(cloud):
    cloud.distro.update_package_sources()

def add_apt_sources(
    srcdict, cloud, target=None, template_params=None, aa_repo_match=None
):
    """
    install keys and repo source .list files defined in 'sources'

for each 'source' entry in the config:
        1. expand template variables and write source .list file in
                /etc/apt/sources.list.d/
        2. install defined keys
        3. update packages via distro-specific method (i.e. apt-key update)

@param srcdict: a dict containing elements required
    @param cloud: cloud instance object

Example srcdict value:
    {
    'rio-grande-repo': {
        'source': 'deb [signed-by=$KEY_FILE] $MIRROR $RELEASE main',
        'keyid': 'B59D 5F15 97A5 04B7 E230  6DCA 0620 BBCF 0368 3F77',
        'keyserver': 'pgp.mit.edu'
        }
    }

Note: Deb822 format is not supported
    """
    if template_params is None:
        template_params = {}

if aa_repo_match is None:
        raise ValueError("did not get a valid repo matcher")

if not isinstance(srcdict, dict):
        raise TypeError("unknown apt format: %s" % (srcdict))

for filename in srcdict:
        ent = srcdict[filename]
        LOG.debug("adding source/key '%s'", ent)
        if "filename" not in ent:
            if target and filename.startswith(target):
                # Strip target path prefix from filename
                ent["filename"] = filename[len(target) :]
            else:
                ent["filename"] = filename

if "source" in ent and "$KEY_FILE" in ent["source"]:
            key_file = add_apt_key(ent, cloud, target, hardened=True)
            template_params["KEY_FILE"] = key_file
        else:
            add_apt_key(ent, cloud, target)

if "source" not in ent:
            continue
        source = ent["source"]
        source = templater.render_string(source, template_params)

if not ent["filename"].startswith("/"):
            ent["filename"] = os.path.join(
                "/etc/apt/sources.list.d/", ent["filename"]
            )
        if not ent["filename"].endswith(".list"):
            ent["filename"] += ".list"

if aa_repo_match(source):
            try:
                subp.subp(
                    ["add-apt-repository", "--no-update", source],
                    target=target,
                )
            except subp.ProcessExecutionError:
                LOG.exception("add-apt-repository failed.")
                raise
            continue

sourcefn = subp.target_path(target, ent["filename"])
        try:
            contents = "%s\n" % (source)
            omode = "a"

if "append" in ent and not ent["append"]:
                omode = "w"

util.write_file(sourcefn, contents, omode=omode)
        except IOError as detail:
            LOG.exception("failed write to file %s: %s", sourcefn, detail)
            raise

update_packages(cloud)

return

def convert_v1_to_v2_apt_format(srclist):
    """convert v1 apt format to v2 (dict in apt_sources)"""
    srcdict = {}
    util.deprecate(
        deprecated="Config key 'apt_sources'",
        deprecated_version="22.1",
        extra_message="Use 'apt' instead",
    )
    if isinstance(srclist, list):
        LOG.debug("apt config: convert V1 to V2 format (source list to dict)")
        for srcent in srclist:
            if "filename" not in srcent:
                # file collides for multiple !filename cases for compatibility
                # yet we need them all processed, so not same dictionary key
                srcent["filename"] = "cloud_config_sources.list"
                key = util.rand_dict_key(srcdict, "cloud_config_sources.list")
            else:
                # all with filename use that as key (matching new format)
                key = srcent["filename"]
            srcdict[key] = srcent
    elif isinstance(srclist, dict):
        srcdict = srclist
    else:
        raise ValueError("unknown apt_sources format")

return srcdict

def convert_key(oldcfg, aptcfg, oldkey, newkey):
    """convert an old key to the new one if the old one exists
    returns true if a key was found and converted"""
    if oldcfg.get(oldkey, None) is not None:
        aptcfg[newkey] = oldcfg.get(oldkey)
        del oldcfg[oldkey]
        return True
    return False

def convert_mirror(oldcfg, aptcfg):
    """convert old apt_mirror keys into the new more advanced mirror spec"""
    keymap = [
        ("apt_mirror", "uri"),
        ("apt_mirror_search", "search"),
        ("apt_mirror_search_dns", "search_dns"),
    ]
    converted = False
    newmcfg = {"arches": ["default"]}
    for oldkey, newkey in keymap:
        if convert_key(oldcfg, newmcfg, oldkey, newkey):
            converted = True

# only insert new style config if anything was converted
    if converted:
        aptcfg["primary"] = [newmcfg]

def convert_v2_to_v3_apt_format(oldcfg):
    """convert old to new keys and adapt restructured mirror spec"""
    mapoldkeys = {
        "apt_sources": "sources",
        "apt_mirror": None,
        "apt_mirror_search": None,
        "apt_mirror_search_dns": None,
        "apt_proxy": "proxy",
        "apt_http_proxy": "http_proxy",
        "apt_ftp_proxy": "https_proxy",
        "apt_https_proxy": "ftp_proxy",
        "apt_preserve_sources_list": "preserve_sources_list",
        "apt_custom_sources_list": "sources_list",
        "add_apt_repo_match": "add_apt_repo_match",
    }
    needtoconvert = []
    for oldkey in mapoldkeys:
        if oldkey in oldcfg:
            if oldcfg[oldkey] in (None, ""):
                del oldcfg[oldkey]
            else:
                needtoconvert.append(oldkey)

# no old config, so no new one to be created
    if not needtoconvert:
        return oldcfg
    util.deprecate(
        deprecated=f"The following config key(s): {needtoconvert}",
        deprecated_version="22.1",
    )

# if old AND new config are provided, prefer the new one (LP #1616831)
    newaptcfg = oldcfg.get("apt", None)
    if newaptcfg is not None:
        util.deprecate(
            deprecated="Support for combined old and new apt module keys",
            deprecated_version="22.1",
        )
        for oldkey in needtoconvert:
            newkey = mapoldkeys[oldkey]
            verify = oldcfg[oldkey]  # drop, but keep a ref for verification
            del oldcfg[oldkey]
            if newkey is None or newaptcfg.get(newkey, None) is None:
                # no simple mapping or no collision on this particular key
                continue
            if verify != newaptcfg[newkey]:
                raise ValueError(
                    "Old and New apt format defined with unequal "
                    "values %s vs %s @ %s"
                    % (verify, newaptcfg[newkey], oldkey)
                )
        # return conf after clearing conflicting V1/2 keys
        return oldcfg

# create new format from old keys
    aptcfg = {}

# simple renames / moves under the apt key
    for oldkey in mapoldkeys:
        if mapoldkeys[oldkey] is not None:
            convert_key(oldcfg, aptcfg, oldkey, mapoldkeys[oldkey])

# mirrors changed in a more complex way
    convert_mirror(oldcfg, aptcfg)

for oldkey in mapoldkeys:
        if oldcfg.get(oldkey, None) is not None:
            raise ValueError("old apt key '%s' left after conversion" % oldkey)

# insert new format into config and return full cfg with only v3 content
    oldcfg["apt"] = aptcfg
    return oldcfg

def convert_to_v3_apt_format(cfg):
    """convert the old list based format to the new dict based one. After that
    convert the old dict keys/format to v3 a.k.a 'new apt config'"""
    # V1 -> V2, the apt_sources entry from list to dict
    apt_sources = cfg.get("apt_sources", None)
    if apt_sources is not None:
        cfg["apt_sources"] = convert_v1_to_v2_apt_format(apt_sources)

# V2 -> V3, move all former globals under the "apt" key
    # Restructure into new key names and mirror hierarchy
    cfg = convert_v2_to_v3_apt_format(cfg)

return cfg

def search_for_mirror_dns(configured, mirrortype, cfg, cloud):
    """
    Try to resolve a list of predefines DNS names to pick mirrors
    """
    mirror = None

if configured:
        mydom = ""
        doms = []

if mirrortype == "primary":
            mirrordns = "mirror"
        elif mirrortype == "security":
            mirrordns = "security-mirror"
        else:
            raise ValueError("unknown mirror type")

# if we have a fqdn, then search its domain portion first
        fqdn = util.get_hostname_fqdn(cfg, cloud).fqdn
        mydom = ".".join(fqdn.split(".")[1:])
        if mydom:
            doms.append(".%s" % mydom)

doms.extend(
            (
                ".localdomain",
                "",
            )
        )

mirror_list = []
        distro = cloud.distro.name
        mirrorfmt = "http://%s-%s%s/%s" % (distro, mirrordns, "%s", distro)
        for post in doms:
            mirror_list.append(mirrorfmt % (post))

mirror = util.search_for_mirror(mirror_list)

return mirror

def update_mirror_info(pmirror, smirror, arch, cloud):
    """sets security mirror to primary if not defined.
    returns defaults if no mirrors are defined"""
    if pmirror is not None:
        if smirror is None:
            smirror = pmirror
        return {"PRIMARY": pmirror, "SECURITY": smirror}

# None specified at all, get default mirrors from cloud
    mirror_info = cloud.datasource.get_package_mirror_info()
    if mirror_info:
        # get_package_mirror_info() returns a dictionary with
        # arbitrary key/value pairs including 'primary' and 'security' keys.
        # caller expects dict with PRIMARY and SECURITY.
        m = mirror_info.copy()
        m["PRIMARY"] = m["primary"]
        m["SECURITY"] = m["security"]

return m

# if neither apt nor cloud configured mirrors fall back to
    return get_default_mirrors(arch)

def get_arch_mirrorconfig(cfg, mirrortype, arch):
    """out of a list of potential mirror configurations select
    and return the one matching the architecture (or default)"""
    # select the mirror specification (if-any)
    mirror_cfg_list = cfg.get(mirrortype, None)
    if mirror_cfg_list is None:
        return None

# select the specification matching the target arch
    default = None
    for mirror_cfg_elem in mirror_cfg_list:
        arches = mirror_cfg_elem.get("arches") or []
        if arch in arches:
            return mirror_cfg_elem
        if "default" in arches:
            default = mirror_cfg_elem
    return default

def get_mirror(cfg, mirrortype, arch, cloud):
    """pass the three potential stages of mirror specification
    returns None is neither of them found anything otherwise the first
    hit is returned"""
    mcfg = get_arch_mirrorconfig(cfg, mirrortype, arch)
    if mcfg is None:
        return None

# directly specified
    mirror = mcfg.get("uri", None)

# fallback to search if specified
    if mirror is None:
        # list of mirrors to try to resolve
        mirror = util.search_for_mirror(mcfg.get("search", None))

# fallback to search_dns if specified
    if mirror is None:
        # list of mirrors to try to resolve
        mirror = search_for_mirror_dns(
            mcfg.get("search_dns", None), mirrortype, cfg, cloud
        )

return mirror

def find_apt_mirror_info(cfg, cloud, arch=None):
    """find_apt_mirror_info
    find an apt_mirror given the cfg provided.
    It can check for separate config of primary and security mirrors
    If only primary is given security is assumed to be equal to primary
    If the generic apt_mirror is given that is defining for both
    """

if arch is None:
        arch = util.get_dpkg_architecture()
        LOG.debug("got arch for mirror selection: %s", arch)
    pmirror = get_mirror(cfg, "primary", arch, cloud)
    LOG.debug("got primary mirror: %s", pmirror)
    smirror = get_mirror(cfg, "security", arch, cloud)
    LOG.debug("got security mirror: %s", smirror)

mirror_info = update_mirror_info(pmirror, smirror, arch, cloud)

# less complex replacements use only MIRROR, derive from primary
    mirror_info["MIRROR"] = mirror_info["PRIMARY"]

return mirror_info

def apply_apt_config(cfg, proxy_fname, config_fname):
    """apply_apt_config
    Applies any apt*proxy config from if specified
    """
    # Set up any apt proxy
    cfgs = (
        ("proxy", 'Acquire::http::Proxy "%s";'),
        ("http_proxy", 'Acquire::http::Proxy "%s";'),
        ("ftp_proxy", 'Acquire::ftp::Proxy "%s";'),
        ("https_proxy", 'Acquire::https::Proxy "%s";'),
    )

proxies = [fmt % cfg.get(name) for (name, fmt) in cfgs if cfg.get(name)]
    if len(proxies):
        LOG.debug("write apt proxy info to %s", proxy_fname)
        util.write_file(proxy_fname, "\n".join(proxies) + "\n")
    elif os.path.isfile(proxy_fname):
        util.del_file(proxy_fname)
        LOG.debug("no apt proxy configured, removed %s", proxy_fname)

if cfg.get("conf", None):
        LOG.debug("write apt config info to %s", config_fname)
        util.write_file(config_fname, cfg.get("conf"))
    elif os.path.isfile(config_fname):
        util.del_file(config_fname)
        LOG.debug("no apt config configured, removed %s", config_fname)

def apt_key(
    command, output_file=None, data=None, hardened=False, human_output=True
):
    """apt-key replacement

commands implemented: 'add', 'list', 'finger'

@param output_file: name of output gpg file (without .gpg or .asc)
    @param data: key contents
    @param human_output: list keys formatted for human parsing
    @param hardened: write keys to to /etc/apt/cloud-init.gpg.d/ (referred to
    with [signed-by] in sources file)
    """

def _get_key_files():
        """return all apt keys

/etc/apt/trusted.gpg (if it exists) and all keyfiles (and symlinks to
        keyfiles) in /etc/apt/trusted.gpg.d/ are returned

based on apt-key implementation
        """
        key_files = [APT_LOCAL_KEYS] if os.path.isfile(APT_LOCAL_KEYS) else []

for file in os.listdir(APT_TRUSTED_GPG_DIR):
            if file.endswith((".gpg", ".asc")):
                key_files.append(APT_TRUSTED_GPG_DIR + file)
        return key_files if key_files else ""

def apt_key_add():
        """apt-key add <file>

returns filepath to new keyring, or '/dev/null' when an error occurs
        """
        file_name = "/dev/null"
        if not output_file:
            util.logexc(
                LOG, 'Unknown filename, failed to add key: "{}"'.format(data)
            )
        else:
            try:
                key_dir = (
                    CLOUD_INIT_GPG_DIR if hardened else APT_TRUSTED_GPG_DIR
                )
                stdout = gpg.dearmor(data)
                file_name = "{}{}.gpg".format(key_dir, output_file)
                util.write_file(file_name, stdout)
            except subp.ProcessExecutionError:
                util.logexc(
                    LOG, "Gpg error, failed to add key: {}".format(data)
                )
            except UnicodeDecodeError:
                util.logexc(
                    LOG, "Decode error, failed to add key: {}".format(data)
                )
        return file_name

def apt_key_list():
        """apt-key list

returns string of all trusted keys (in /etc/apt/trusted.gpg and
        /etc/apt/trusted.gpg.d/)
        """
        key_list = []
        for key_file in _get_key_files():
            try:
                key_list.append(gpg.list(key_file, human_output=human_output))
            except subp.ProcessExecutionError as error:
                LOG.warning('Failed to list key "%s": %s', key_file, error)
        return "\n".join(key_list)

if command == "add":
        return apt_key_add()
    elif command == "finger" or command == "list":
        return apt_key_list()
    else:
        raise ValueError(
            "apt_key() commands add, list, and finger are currently supported"
        )

CONFIG_CLEANERS = {
    "cloud-init": clean_cloud_init,
}

MR SKB