# Author: Jonas Keidel <jonas.keidel@hetzner.com>
# Author: Markus Schade <markus.schade@hetzner.com>
#
# This file is part of cloud-init. See LICENSE file for license information.
#
"""Hetzner Cloud API Documentation
   https://docs.hetzner.cloud/"""

from cloudinit import dmi
from cloudinit import log as logging
from cloudinit import net as cloudnet
from cloudinit import sources
from cloudinit import util

import cloudinit.sources.helpers.hetzner as hc_helper

LOG = logging.getLogger(__name__)

BASE_URL_V1 = 'http://169.254.169.254/hetzner/v1'

BUILTIN_DS_CONFIG = {
    'metadata_url': BASE_URL_V1 + '/metadata',
    'userdata_url': BASE_URL_V1 + '/userdata',
}

MD_RETRIES = 60
MD_TIMEOUT = 2
MD_WAIT_RETRY = 2


class DataSourceHetzner(sources.DataSource):

    dsname = 'Hetzner'

    def __init__(self, sys_cfg, distro, paths):
        sources.DataSource.__init__(self, sys_cfg, distro, paths)
        self.distro = distro
        self.metadata = dict()
        self.ds_cfg = util.mergemanydict([
            util.get_cfg_by_path(sys_cfg, ["datasource", "Hetzner"], {}),
            BUILTIN_DS_CONFIG])
        self.metadata_address = self.ds_cfg['metadata_url']
        self.userdata_address = self.ds_cfg['userdata_url']
        self.retries = self.ds_cfg.get('retries', MD_RETRIES)
        self.timeout = self.ds_cfg.get('timeout', MD_TIMEOUT)
        self.wait_retry = self.ds_cfg.get('wait_retry', MD_WAIT_RETRY)
        self._network_config = None
        self.dsmode = sources.DSMODE_NETWORK

    def _get_data(self):
        (on_hetzner, serial) = get_hcloud_data()

        if not on_hetzner:
            return False

        nic = cloudnet.find_fallback_nic()
        with cloudnet.EphemeralIPv4Network(nic, "169.254.0.1", 16,
                                           "169.254.255.255"):
            md = hc_helper.read_metadata(
                self.metadata_address, timeout=self.timeout,
                sec_between=self.wait_retry, retries=self.retries)
            ud = hc_helper.read_userdata(
                self.userdata_address, timeout=self.timeout,
                sec_between=self.wait_retry, retries=self.retries)

        # Hetzner cloud does not support binary user-data. So here, do a
        # base64 decode of the data if we can. The end result being that a
        # user can provide base64 encoded (possibly gzipped) data as user-data.
        #
        # The fallout is that in the event of b64 encoded user-data,
        # /var/lib/cloud-init/cloud-config.txt will not be identical to the
        # user-data provided.  It will be decoded.
        self.userdata_raw = hc_helper.maybe_b64decode(ud)
        self.metadata_full = md

        # hostname is name provided by user at launch.  The API enforces it is
        # a valid hostname, but it is not guaranteed to be resolvable in dns or
        # fully qualified.
        self.metadata['instance-id'] = md['instance-id']
        self.metadata['local-hostname'] = md['hostname']
        self.metadata['network-config'] = md.get('network-config', None)
        self.metadata['public-keys'] = md.get('public-keys', None)
        self.vendordata_raw = md.get("vendor_data", None)

        # instance-id and serial from SMBIOS should be identical
        if self.get_instance_id() != serial:
            raise RuntimeError(
                "SMBIOS serial does not match instance ID from metadata"
            )

        return True

    def check_instance_id(self, sys_cfg):
        return sources.instance_id_matches_system_uuid(
            self.get_instance_id(), 'system-serial-number')

    @property
    def network_config(self):
        """Configure the networking. This needs to be done each boot, since
           the IP information may have changed due to snapshot and/or
           migration.
        """

        if self._network_config:
            return self._network_config

        _net_config = self.metadata['network-config']
        if not _net_config:
            raise Exception("Unable to get meta-data from server....")

        self._network_config = _net_config

        return self._network_config


def get_hcloud_data():
    vendor_name = dmi.read_dmi_data('system-manufacturer')
    if vendor_name != "Hetzner":
        return (False, None)

    serial = dmi.read_dmi_data("system-serial-number")
    if serial:
        LOG.debug("Running on Hetzner Cloud: serial=%s", serial)
    else:
        raise RuntimeError("Hetzner Cloud detected, but no serial found")

    return (True, serial)


# Used to match classes to dependencies
datasources = [
    (DataSourceHetzner, (sources.DEP_FILESYSTEM, )),
]


# Return a list of data sources that match this set of dependencies
def get_datasource_list(depends):
    return sources.list_from_depends(depends, datasources)

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