Current File : //lib/python3/dist-packages/cloudinit/sources/DataSourceGCE.py
# Author: Vaidas Jablonskis <jablonskis@gmail.com>
#
# This file is part of cloud-init. See LICENSE file for license information.
import datetime
import json
from base64 import b64decode
from contextlib import suppress as noop
from cloudinit import dmi
from cloudinit import log as logging
from cloudinit import sources, url_helper, util
from cloudinit.distros import ug_util
from cloudinit.net.ephemeral import EphemeralDHCPv4
from cloudinit.sources import DataSourceHostname
LOG = logging.getLogger(__name__)
MD_V1_URL = "http://metadata.google.internal/computeMetadata/v1/"
BUILTIN_DS_CONFIG = {"metadata_url": MD_V1_URL}
REQUIRED_FIELDS = ("instance-id", "availability-zone", "local-hostname")
GUEST_ATTRIBUTES_URL = (
"http://metadata.google.internal/computeMetadata/"
"v1/instance/guest-attributes"
)
HOSTKEY_NAMESPACE = "hostkeys"
HEADERS = {"Metadata-Flavor": "Google"}
class GoogleMetadataFetcher:
def __init__(self, metadata_address, num_retries, sec_between_retries):
self.metadata_address = metadata_address
self.num_retries = num_retries
self.sec_between_retries = sec_between_retries
def get_value(self, path, is_text, is_recursive=False):
value = None
try:
url = self.metadata_address + path
if is_recursive:
url += "/?recursive=True"
resp = url_helper.readurl(
url=url,
headers=HEADERS,
retries=self.num_retries,
sec_between=self.sec_between_retries,
)
except url_helper.UrlError as exc:
msg = "url %s raised exception %s"
LOG.debug(msg, path, exc)
else:
if resp.code == 200:
if is_text:
value = util.decode_binary(resp.contents)
else:
value = resp.contents.decode("utf-8")
else:
LOG.debug("url %s returned code %s", path, resp.code)
return value
class DataSourceGCE(sources.DataSource):
dsname = "GCE"
perform_dhcp_setup = False
def __init__(self, sys_cfg, distro, paths):
sources.DataSource.__init__(self, sys_cfg, distro, paths)
self.default_user = None
if distro:
(users, _groups) = ug_util.normalize_users_groups(sys_cfg, distro)
(self.default_user, _user_config) = ug_util.extract_default(users)
self.metadata = dict()
self.ds_cfg = util.mergemanydict(
[
util.get_cfg_by_path(sys_cfg, ["datasource", "GCE"], {}),
BUILTIN_DS_CONFIG,
]
)
self.metadata_address = self.ds_cfg["metadata_url"]
def _get_data(self):
url_params = self.get_url_params()
network_context = noop()
if self.perform_dhcp_setup:
network_context = EphemeralDHCPv4(
self.fallback_interface,
tmp_dir=self.distro.get_tmp_exec_path(),
)
with network_context:
ret = util.log_time(
LOG.debug,
"Crawl of GCE metadata service",
read_md,
kwargs={
"address": self.metadata_address,
"url_params": url_params,
},
)
if not ret["success"]:
if ret["platform_reports_gce"]:
LOG.warning(ret["reason"])
else:
LOG.debug(ret["reason"])
return False
self.metadata = ret["meta-data"]
self.userdata_raw = ret["user-data"]
return True
@property
def launch_index(self):
# GCE does not provide lauch_index property.
return None
def get_instance_id(self):
return self.metadata["instance-id"]
def get_public_ssh_keys(self):
public_keys_data = self.metadata["public-keys-data"]
return _parse_public_keys(public_keys_data, self.default_user)
def publish_host_keys(self, hostkeys):
for key in hostkeys:
_write_host_key_to_guest_attributes(*key)
def get_hostname(self, fqdn=False, resolve_ip=False, metadata_only=False):
# GCE has long FDQN's and has asked for short hostnames.
return DataSourceHostname(
self.metadata["local-hostname"].split(".")[0], False
)
@property
def availability_zone(self):
return self.metadata["availability-zone"]
@property
def region(self):
return self.availability_zone.rsplit("-", 1)[0]
class DataSourceGCELocal(DataSourceGCE):
perform_dhcp_setup = True
def _write_host_key_to_guest_attributes(key_type, key_value):
url = "%s/%s/%s" % (GUEST_ATTRIBUTES_URL, HOSTKEY_NAMESPACE, key_type)
key_value = key_value.encode("utf-8")
resp = url_helper.readurl(
url=url,
data=key_value,
headers=HEADERS,
request_method="PUT",
check_status=False,
)
if resp.ok():
LOG.debug("Wrote %s host key to guest attributes.", key_type)
else:
LOG.debug("Unable to write %s host key to guest attributes.", key_type)
def _has_expired(public_key):
# Check whether an SSH key is expired. Public key input is a single SSH
# public key in the GCE specific key format documented here:
# https://cloud.google.com/compute/docs/instances/adding-removing-ssh-keys#sshkeyformat
try:
# Check for the Google-specific schema identifier.
schema, json_str = public_key.split(None, 3)[2:]
except (ValueError, AttributeError):
return False
# Do not expire keys if they do not have the expected schema identifier.
if schema != "google-ssh":
return False
try:
json_obj = json.loads(json_str)
except ValueError:
return False
# Do not expire keys if there is no expriation timestamp.
if "expireOn" not in json_obj:
return False
expire_str = json_obj["expireOn"]
format_str = "%Y-%m-%dT%H:%M:%S+0000"
try:
expire_time = datetime.datetime.strptime(expire_str, format_str)
except ValueError:
return False
# Expire the key if and only if we have exceeded the expiration timestamp.
return datetime.datetime.utcnow() > expire_time
def _parse_public_keys(public_keys_data, default_user=None):
# Parse the SSH key data for the default user account. Public keys input is
# a list containing SSH public keys in the GCE specific key format
# documented here:
# https://cloud.google.com/compute/docs/instances/adding-removing-ssh-keys#sshkeyformat
public_keys = []
if not public_keys_data:
return public_keys
for public_key in public_keys_data:
if not public_key or not all(ord(c) < 128 for c in public_key):
continue
split_public_key = public_key.split(":", 1)
if len(split_public_key) != 2:
continue
user, key = split_public_key
if user in ("cloudinit", default_user) and not _has_expired(key):
public_keys.append(key)
return public_keys
def read_md(address=None, url_params=None, platform_check=True):
if address is None:
address = MD_V1_URL
ret = {
"meta-data": None,
"user-data": None,
"success": False,
"reason": None,
}
ret["platform_reports_gce"] = platform_reports_gce()
if platform_check and not ret["platform_reports_gce"]:
ret["reason"] = "Not running on GCE."
return ret
# If we cannot resolve the metadata server, then no point in trying.
if not util.is_resolvable_url(address):
LOG.debug("%s is not resolvable", address)
ret["reason"] = 'address "%s" is not resolvable' % address
return ret
# url_map: (our-key, path, required, is_text, is_recursive)
url_map = [
("instance-id", ("instance/id",), True, True, False),
("availability-zone", ("instance/zone",), True, True, False),
("local-hostname", ("instance/hostname",), True, True, False),
("instance-data", ("instance/attributes",), False, False, True),
("project-data", ("project/attributes",), False, False, True),
]
metadata_fetcher = GoogleMetadataFetcher(
address, url_params.num_retries, url_params.sec_between_retries
)
md = {}
# Iterate over url_map keys to get metadata items.
for (mkey, paths, required, is_text, is_recursive) in url_map:
value = None
for path in paths:
new_value = metadata_fetcher.get_value(path, is_text, is_recursive)
if new_value is not None:
value = new_value
if required and value is None:
msg = "required key %s returned nothing. not GCE"
ret["reason"] = msg % mkey
return ret
md[mkey] = value
instance_data = json.loads(md["instance-data"] or "{}")
project_data = json.loads(md["project-data"] or "{}")
valid_keys = [instance_data.get("sshKeys"), instance_data.get("ssh-keys")]
block_project = instance_data.get("block-project-ssh-keys", "").lower()
if block_project != "true" and not instance_data.get("sshKeys"):
valid_keys.append(project_data.get("ssh-keys"))
valid_keys.append(project_data.get("sshKeys"))
public_keys_data = "\n".join([key for key in valid_keys if key])
md["public-keys-data"] = public_keys_data.splitlines()
if md["availability-zone"]:
md["availability-zone"] = md["availability-zone"].split("/")[-1]
if "user-data" in instance_data:
# instance_data was json, so values are all utf-8 strings.
ud = instance_data["user-data"].encode("utf-8")
encoding = instance_data.get("user-data-encoding")
if encoding == "base64":
ud = b64decode(ud)
elif encoding:
LOG.warning("unknown user-data-encoding: %s, ignoring", encoding)
ret["user-data"] = ud
ret["meta-data"] = md
ret["success"] = True
return ret
def platform_reports_gce():
pname = dmi.read_dmi_data("system-product-name") or "N/A"
if pname == "Google Compute Engine" or pname == "Google":
return True
# system-product-name is not always guaranteed (LP: #1674861)
serial = dmi.read_dmi_data("system-serial-number") or "N/A"
if serial.startswith("GoogleCloud-"):
return True
LOG.debug(
"Not running on google cloud. product-name=%s serial=%s", pname, serial
)
return False
# Used to match classes to dependencies.
datasources = [
(DataSourceGCELocal, (sources.DEP_FILESYSTEM,)),
(DataSourceGCE, (sources.DEP_FILESYSTEM, sources.DEP_NETWORK)),
]
# Return a list of data sources that match this set of dependencies.
def get_datasource_list(depends):
return sources.list_from_depends(depends, datasources)
if __name__ == "__main__":
import argparse
import sys
from base64 import b64encode
parser = argparse.ArgumentParser(description="Query GCE Metadata Service")
parser.add_argument(
"--endpoint",
metavar="URL",
help="The url of the metadata service.",
default=MD_V1_URL,
)
parser.add_argument(
"--no-platform-check",
dest="platform_check",
help="Ignore smbios platform check",
action="store_false",
default=True,
)
args = parser.parse_args()
data = read_md(address=args.endpoint, platform_check=args.platform_check)
if "user-data" in data:
# user-data is bytes not string like other things. Handle it specially.
# If it can be represented as utf-8 then do so. Otherwise print base64
# encoded value in the key user-data-b64.
try:
data["user-data"] = data["user-data"].decode()
except UnicodeDecodeError:
sys.stderr.write(
"User-data cannot be decoded. Writing as base64\n"
)
del data["user-data"]
# b64encode returns a bytes value. Decode to get the string.
data["user-data-b64"] = b64encode(data["user-data"]).decode()
print(json.dumps(data, indent=1, sort_keys=True, separators=(",", ": ")))
# vi: ts=4 expandtab
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