Source code for

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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 import ComputeEngineHook
from 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()
        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] conn_type = "gcpssh"
[docs] hook_name = "Google Cloud SSH"
[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 = 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._compute_hook._get_field("zone", self.user = conn.login if conn.login else self.user # self.project_id is skipped intentionally self.hostname = if 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 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!" ) "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.use_internal_ip, self.use_iap_tunnel, self.use_oslogin, ) if not self.hostname: hostname = self._compute_hook.get_instance_address(, 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={}", "--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:"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"Failed to connect. Waiting %ds to retry", time_to_wait) time.sleep(time_to_wait) raise AirflowException("Can not connect to instance") def _authorize_compute_engine_instance_metadata(self, pubkey):"Appending SSH public key to instance metadata") instance_info = self._compute_hook.get_instance_info(, 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(, 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()"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:"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}")

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