authentik/authentik/outposts/controllers/k8s/base.py

"""Base Kubernetes Reconciler"""
from typing import TYPE_CHECKING, Generic, TypeVar

from django.utils.text import slugify
from kubernetes.client import V1ObjectMeta
from kubernetes.client.exceptions import ApiException, OpenApiException
from kubernetes.client.models.v1_deployment import V1Deployment
from kubernetes.client.models.v1_pod import V1Pod
from structlog.stdlib import get_logger
from urllib3.exceptions import HTTPError

from authentik import __version__
from authentik.lib.sentry import SentryIgnoredException
from authentik.outposts.managed import MANAGED_OUTPOST

if TYPE_CHECKING:
    from authentik.outposts.controllers.kubernetes import KubernetesController

# pylint: disable=invalid-name
T = TypeVar("T", V1Pod, V1Deployment)


class ReconcileTrigger(SentryIgnoredException):
    """Base trigger raised by child classes to notify us"""


class NeedsRecreate(ReconcileTrigger):
    """Exception to trigger a complete recreate of the Kubernetes Object"""


class NeedsUpdate(ReconcileTrigger):
    """Exception to trigger an update to the Kubernetes Object"""


class KubernetesObjectReconciler(Generic[T]):
    """Base Kubernetes Reconciler, handles the basic logic."""

    controller: "KubernetesController"

    def __init__(self, controller: "KubernetesController"):
        self.controller = controller
        self.namespace = controller.outpost.config.kubernetes_namespace
        self.logger = get_logger().bind(type=self.__class__.__name__)

    @property
    def is_embedded(self) -> bool:
        """Return true if the current outpost is embedded"""
        return self.controller.outpost.managed == MANAGED_OUTPOST

    @property
    def noop(self) -> bool:
        """Return true if this object should not be created/updated/deleted in this cluster"""
        return False

    @property
    def name(self) -> str:
        """Get the name of the object this reconciler manages"""
        return (
            self.controller.outpost.config.object_naming_template
            % {
                "name": slugify(self.controller.outpost.name),
                "uuid": self.controller.outpost.uuid.hex,
            }
        ).lower()

    def up(self):
        """Create object if it doesn't exist, update if needed or recreate if needed."""
        current = None
        if self.noop:
            self.logger.debug("Object is noop")
            return
        reference = self.get_reference_object()
        try:
            try:
                current = self.retrieve()
            except (OpenApiException, HTTPError) as exc:
                # pylint: disable=no-member
                if isinstance(exc, ApiException) and exc.status == 404:
                    self.logger.debug("Failed to get current, triggering recreate")
                    raise NeedsRecreate from exc
                self.logger.debug("Other unhandled error", exc=exc)
                raise exc
            else:
                self.reconcile(current, reference)
        except NeedsRecreate:
            self.logger.debug("Recreate requested")
            if current:
                self.logger.debug("Deleted old")
                self.delete(current)
            else:
                self.logger.debug("No old found, creating")
            self.logger.debug("Creating")
            self.create(reference)
        except NeedsUpdate:
            self.logger.debug("Updating")
            self.update(current, reference)
        else:
            self.logger.debug("Object is up-to-date.")

    def down(self):
        """Delete object if found"""
        if self.noop:
            self.logger.debug("Object is noop")
            return
        try:
            current = self.retrieve()
            self.delete(current)
            self.logger.debug("Removing")
        except (OpenApiException, HTTPError) as exc:
            # pylint: disable=no-member
            if isinstance(exc, ApiException) and exc.status == 404:
                self.logger.debug("Failed to get current, assuming non-existant")
                return
            self.logger.debug("Other unhandled error", exc=exc)
            raise exc

    def get_reference_object(self) -> T:
        """Return object as it should be"""
        raise NotImplementedError

    def reconcile(self, current: T, reference: T):
        """Check what operations should be done, should be raised as
        ReconcileTrigger"""
        if current.metadata.labels != reference.metadata.labels:
            raise NeedsUpdate()

    def create(self, reference: T):
        """API Wrapper to create object"""
        raise NotImplementedError

    def retrieve(self) -> T:
        """API Wrapper to retrive object"""
        raise NotImplementedError

    def delete(self, reference: T):
        """API Wrapper to delete object"""
        raise NotImplementedError

    def update(self, current: T, reference: T):
        """API Wrapper to update object"""
        raise NotImplementedError

    def get_object_meta(self, **kwargs) -> V1ObjectMeta:
        """Get common object metadata"""
        return V1ObjectMeta(
            namespace=self.namespace,
            labels={
                "app.kubernetes.io/name": f"authentik-{self.controller.outpost.type.lower()}",
                "app.kubernetes.io/instance": slugify(self.controller.outpost.name),
                "app.kubernetes.io/version": __version__,
                "app.kubernetes.io/managed-by": "goauthentik.io",
                "goauthentik.io/outpost-uuid": self.controller.outpost.uuid.hex,
            },
            **kwargs,
        )