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# regarding copyright ownership. The ASF licenses this file
# to you under the Apache License, Version 2.0 (the
# "License"); you may not use this file except in compliance
# with the License. You may obtain a copy of the License at
#
# http://www.apache.org/licenses/LICENSE-2.0
#
# Unless required by applicable law or agreed to in writing,
# software distributed under the License is distributed on an
# "AS IS" BASIS, WITHOUT WARRANTIES OR CONDITIONS OF ANY
# KIND, either express or implied. See the License for the
# specific language governing permissions and limitations
# under the License.
from __future__ import annotations
import shlex
import time
from io import StringIO
from typing import Any
from google.api_core.retry import exponential_sleep_generator
from airflow import AirflowException
from airflow.compat.functools import cached_property
from airflow.providers.google.cloud.hooks.compute import ComputeEngineHook
from airflow.providers.google.cloud.hooks.os_login import OSLoginHook
from airflow.providers.ssh.hooks.ssh import SSHHook
# Paramiko should be imported after airflow.providers.ssh. Then the import will fail with
# cannot import "airflow.providers.ssh" and will be correctly discovered as optional feature
# TODO:(potiuk) We should add test harness detecting such cases shortly
import paramiko # isort:skip
class _GCloudAuthorizedSSHClient(paramiko.SSHClient):
"""SSH Client that maintains the context for gcloud authorization during the connection"""
def __init__(self, google_hook, *args, **kwargs):
super().__init__(*args, **kwargs)
self.ssh_client = paramiko.SSHClient()
self.google_hook = google_hook
self.decorator = None
def connect(self, *args, **kwargs):
self.decorator = self.google_hook.provide_authorized_gcloud()
self.decorator.__enter__()
return super().connect(*args, **kwargs)
def close(self):
if self.decorator:
self.decorator.__exit__(None, None, None)
self.decorator = None
return super().close()
def __exit__(self, type_, value, traceback):
if self.decorator:
self.decorator.__exit__(type_, value, traceback)
self.decorator = None
return super().__exit__(type_, value, traceback)
[docs]class ComputeEngineSSHHook(SSHHook):
"""
Hook to connect to a remote instance in compute engine
:param instance_name: The name of the Compute Engine instance
:param zone: The zone of the Compute Engine instance
:param user: The name of the user on which the login attempt will be made
:param project_id: The project ID of the remote instance
:param gcp_conn_id: The connection id to use when fetching connection info
:param hostname: The hostname of the target instance. If it is not passed, it will be detected
automatically.
:param use_iap_tunnel: Whether to connect through IAP tunnel
:param use_internal_ip: Whether to connect using internal IP
:param use_oslogin: Whether to manage keys using OsLogin API. If false,
keys are managed using instance metadata
:param expire_time: The maximum amount of time in seconds before the private key expires
:param gcp_conn_id: The connection id to use when fetching connection information
:param delegate_to: The account to impersonate, if any.
For this to work, the service account making the request must have
domain-wide delegation enabled.
"""
[docs] conn_name_attr = 'gcp_conn_id'
[docs] default_conn_name = 'google_cloud_ssh_default'
[docs] hook_name = 'Google Cloud SSH'
@staticmethod
[docs] def get_ui_field_behaviour() -> dict[str, Any]:
return {
"hidden_fields": ['host', 'schema', 'login', 'password', 'port', 'extra'],
"relabeling": {},
}
def __init__(
self,
gcp_conn_id: str = 'google_cloud_default',
instance_name: str | None = None,
zone: str | None = None,
user: str | None = 'root',
project_id: str | None = None,
hostname: str | None = None,
use_internal_ip: bool = False,
use_iap_tunnel: bool = False,
use_oslogin: bool = True,
expire_time: int = 300,
delegate_to: str | None = None,
) -> None:
# Ignore original constructor
# super().__init__()
self.instance_name = instance_name
self.zone = zone
self.user = user
self.project_id = project_id
self.hostname = hostname
self.use_internal_ip = use_internal_ip
self.use_iap_tunnel = use_iap_tunnel
self.use_oslogin = use_oslogin
self.expire_time = expire_time
self.gcp_conn_id = gcp_conn_id
self.delegate_to = delegate_to
self._conn: Any | None = None
@cached_property
def _oslogin_hook(self) -> OSLoginHook:
return OSLoginHook(gcp_conn_id=self.gcp_conn_id, delegate_to=self.delegate_to)
@cached_property
def _compute_hook(self) -> ComputeEngineHook:
return ComputeEngineHook(gcp_conn_id=self.gcp_conn_id, delegate_to=self.delegate_to)
def _load_connection_config(self):
def _boolify(value):
if isinstance(value, bool):
return value
if isinstance(value, str):
if value.lower() == 'false':
return False
elif value.lower() == 'true':
return True
return False
def intify(key, value, default):
if value is None:
return default
if isinstance(value, str) and value.strip() == '':
return default
try:
return int(value)
except ValueError:
raise AirflowException(
f"The {key} field should be a integer. "
f"Current value: \"{value}\" (type: {type(value)}). "
f"Please check the connection configuration."
)
conn = self.get_connection(self.gcp_conn_id)
if conn and conn.conn_type == "gcpssh":
self.instance_name = self._compute_hook._get_field("instance_name", self.instance_name)
self.zone = self._compute_hook._get_field("zone", self.zone)
self.user = conn.login if conn.login else self.user
# self.project_id is skipped intentionally
self.hostname = conn.host if conn.host else self.hostname
self.use_internal_ip = _boolify(self._compute_hook._get_field("use_internal_ip"))
self.use_iap_tunnel = _boolify(self._compute_hook._get_field("use_iap_tunnel"))
self.use_oslogin = _boolify(self._compute_hook._get_field("use_oslogin"))
self.expire_time = intify(
"expire_time",
self._compute_hook._get_field("expire_time"),
self.expire_time,
)
[docs] def get_conn(self) -> paramiko.SSHClient:
"""Return SSH connection."""
self._load_connection_config()
if not self.project_id:
self.project_id = self._compute_hook.project_id
missing_fields = [k for k in ["instance_name", "zone", "project_id"] if not getattr(self, k)]
if not self.instance_name or not self.zone or not self.project_id:
raise AirflowException(
f"Required parameters are missing: {missing_fields}. These parameters be passed either as "
"keyword parameter or as extra field in Airflow connection definition. Both are not set!"
)
self.log.info(
"Connecting to instance: instance_name=%s, user=%s, zone=%s, "
"use_internal_ip=%s, use_iap_tunnel=%s, use_os_login=%s",
self.instance_name,
self.user,
self.zone,
self.use_internal_ip,
self.use_iap_tunnel,
self.use_oslogin,
)
if not self.hostname:
hostname = self._compute_hook.get_instance_address(
zone=self.zone,
resource_id=self.instance_name,
project_id=self.project_id,
use_internal_ip=self.use_internal_ip or self.use_iap_tunnel,
)
else:
hostname = self.hostname
privkey, pubkey = self._generate_ssh_key(self.user)
if self.use_oslogin:
user = self._authorize_os_login(pubkey)
else:
user = self.user
self._authorize_compute_engine_instance_metadata(pubkey)
proxy_command = None
if self.use_iap_tunnel:
proxy_command_args = [
'gcloud',
'compute',
'start-iap-tunnel',
str(self.instance_name),
'22',
'--listen-on-stdin',
f'--project={self.project_id}',
f'--zone={self.zone}',
'--verbosity=warning',
]
proxy_command = " ".join(shlex.quote(arg) for arg in proxy_command_args)
sshclient = self._connect_to_instance(user, hostname, privkey, proxy_command)
return sshclient
def _connect_to_instance(self, user, hostname, pkey, proxy_command) -> paramiko.SSHClient:
self.log.info("Opening remote connection to host: username=%s, hostname=%s", user, hostname)
max_time_to_wait = 10
for time_to_wait in exponential_sleep_generator(initial=1, maximum=max_time_to_wait):
try:
client = _GCloudAuthorizedSSHClient(self._compute_hook)
# Default is RejectPolicy
# No known host checking since we are not storing privatekey
client.set_missing_host_key_policy(paramiko.AutoAddPolicy())
client.connect(
hostname=hostname,
username=user,
pkey=pkey,
sock=paramiko.ProxyCommand(proxy_command) if proxy_command else None,
look_for_keys=False,
)
return client
except paramiko.SSHException:
# exponential_sleep_generator is an infinite generator, so we need to
# check the end condition.
if time_to_wait == max_time_to_wait:
raise
self.log.info("Failed to connect. Waiting %ds to retry", time_to_wait)
time.sleep(time_to_wait)
raise AirflowException("Caa not connect to instance")
def _authorize_compute_engine_instance_metadata(self, pubkey):
self.log.info("Appending SSH public key to instance metadata")
instance_info = self._compute_hook.get_instance_info(
zone=self.zone, resource_id=self.instance_name, project_id=self.project_id
)
keys = self.user + ":" + pubkey + "\n"
metadata = instance_info['metadata']
items = metadata.get("items", [])
for item in items:
if item.get("key") == "ssh-keys":
keys += item["value"]
item['value'] = keys
break
else:
new_dict = dict(key='ssh-keys', value=keys)
metadata['items'] = [new_dict]
self._compute_hook.set_instance_metadata(
zone=self.zone, resource_id=self.instance_name, metadata=metadata, project_id=self.project_id
)
def _authorize_os_login(self, pubkey):
username = self._oslogin_hook._get_credentials_email()
self.log.info("Importing SSH public key using OSLogin: user=%s", username)
expiration = int((time.time() + self.expire_time) * 1000000)
ssh_public_key = {"key": pubkey, "expiration_time_usec": expiration}
response = self._oslogin_hook.import_ssh_public_key(
user=username, ssh_public_key=ssh_public_key, project_id=self.project_id
)
profile = response.login_profile
account = profile.posix_accounts[0]
user = account.username
return user
def _generate_ssh_key(self, user):
try:
self.log.info("Generating ssh keys...")
pkey_file = StringIO()
pkey_obj = paramiko.RSAKey.generate(2048)
pkey_obj.write_private_key(pkey_file)
pubkey = f"{pkey_obj.get_name()} {pkey_obj.get_base64()} {user}"
return pkey_obj, pubkey
except (OSError, paramiko.SSHException) as err:
raise AirflowException(f"Error encountered creating ssh keys, {err}")
