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"""Executes task in a Kubernetes POD"""
import json
import logging
import re
import sys
import warnings
from contextlib import AbstractContextManager
from typing import TYPE_CHECKING, Any, Dict, List, Optional, Sequence
from kubernetes.client import CoreV1Api, models as k8s
from airflow.exceptions import AirflowException
from airflow.kubernetes import kube_client, pod_generator
from airflow.kubernetes.pod_generator import PodGenerator
from airflow.kubernetes.secret import Secret
from airflow.models import BaseOperator
from airflow.providers.cncf.kubernetes.backcompat.backwards_compat_converters import (
convert_affinity,
convert_configmap,
convert_env_vars,
convert_image_pull_secrets,
convert_pod_runtime_info_env,
convert_port,
convert_resources,
convert_toleration,
convert_volume,
convert_volume_mount,
)
from airflow.providers.cncf.kubernetes.utils import xcom_sidecar # type: ignore[attr-defined]
from airflow.providers.cncf.kubernetes.utils.pod_manager import (
PodLaunchFailedException,
PodManager,
PodPhase,
get_container_termination_message,
)
from airflow.settings import pod_mutation_hook
from airflow.utils import yaml
from airflow.utils.helpers import prune_dict, validate_key
from airflow.version import version as airflow_version
if sys.version_info >= (3, 8):
from functools import cached_property
else:
from cached_property import cached_property
if TYPE_CHECKING:
import jinja2
from airflow.utils.context import Context
[docs]class PodReattachFailure(AirflowException):
"""When we expect to be able to find a pod but cannot."""
[docs]class KubernetesPodOperator(BaseOperator):
"""
Execute a task in a Kubernetes Pod
.. seealso::
For more information on how to use this operator, take a look at the guide:
:ref:`howto/operator:KubernetesPodOperator`
.. note::
If you use `Google Kubernetes Engine <https://cloud.google.com/kubernetes-engine/>`__
and Airflow is not running in the same cluster, consider using
:class:`~airflow.providers.google.cloud.operators.kubernetes_engine.GKEStartPodOperator`, which
simplifies the authorization process.
:param namespace: the namespace to run within kubernetes.
:param image: Docker image you wish to launch. Defaults to hub.docker.com,
but fully qualified URLS will point to custom repositories. (templated)
:param name: name of the pod in which the task will run, will be used (plus a random
suffix if random_name_suffix is True) to generate a pod id (DNS-1123 subdomain,
containing only [a-z0-9.-]).
:param random_name_suffix: if True, will generate a random suffix.
:param cmds: entrypoint of the container. (templated)
The docker images's entrypoint is used if this is not provided.
:param arguments: arguments of the entrypoint. (templated)
The docker image's CMD is used if this is not provided.
:param ports: ports for the launched pod.
:param volume_mounts: volumeMounts for the launched pod.
:param volumes: volumes for the launched pod. Includes ConfigMaps and PersistentVolumes.
:param env_vars: Environment variables initialized in the container. (templated)
:param secrets: Kubernetes secrets to inject in the container.
They can be exposed as environment vars or files in a volume.
:param in_cluster: run kubernetes client with in_cluster configuration.
:param cluster_context: context that points to kubernetes cluster.
Ignored when in_cluster is True. If None, current-context is used.
:param reattach_on_restart: if the worker dies while the pod is running, reattach and monitor
during the next try. If False, always create a new pod for each try.
:param labels: labels to apply to the Pod. (templated)
:param startup_timeout_seconds: timeout in seconds to startup the pod.
:param get_logs: get the stdout of the container as logs of the tasks.
:param image_pull_policy: Specify a policy to cache or always pull an image.
:param annotations: non-identifying metadata you can attach to the Pod.
Can be a large range of data, and can include characters
that are not permitted by labels.
:param resources: resources for the launched pod.
:param affinity: affinity scheduling rules for the launched pod.
:param config_file: The path to the Kubernetes config file. (templated)
If not specified, default value is ``~/.kube/config``
:param node_selector: A dict containing a group of scheduling rules.
:param image_pull_secrets: Any image pull secrets to be given to the pod.
If more than one secret is required, provide a
comma separated list: secret_a,secret_b
:param service_account_name: Name of the service account
:param is_delete_operator_pod: What to do when the pod reaches its final
state, or the execution is interrupted. If True (default), delete the
pod; if False, leave the pod.
:param hostnetwork: If True enable host networking on the pod.
:param tolerations: A list of kubernetes tolerations.
:param security_context: security options the pod should run with (PodSecurityContext).
:param dnspolicy: dnspolicy for the pod.
:param schedulername: Specify a schedulername for the pod
:param full_pod_spec: The complete podSpec
:param init_containers: init container for the launched Pod
:param log_events_on_failure: Log the pod's events if a failure occurs
:param do_xcom_push: If True, the content of the file
/airflow/xcom/return.json in the container will also be pushed to an
XCom when the container completes.
:param pod_template_file: path to pod template file (templated)
:param priority_class_name: priority class name for the launched Pod
:param termination_grace_period: Termination grace period if task killed in UI,
defaults to kubernetes default
"""
[docs] BASE_CONTAINER_NAME = 'base'
[docs] POD_CHECKED_KEY = 'already_checked'
[docs] template_fields: Sequence[str] = (
'image',
'cmds',
'arguments',
'env_vars',
'labels',
'config_file',
'pod_template_file',
'namespace',
)
def __init__(
self,
*,
namespace: Optional[str] = None,
image: Optional[str] = None,
name: Optional[str] = None,
random_name_suffix: Optional[bool] = True,
cmds: Optional[List[str]] = None,
arguments: Optional[List[str]] = None,
ports: Optional[List[k8s.V1ContainerPort]] = None,
volume_mounts: Optional[List[k8s.V1VolumeMount]] = None,
volumes: Optional[List[k8s.V1Volume]] = None,
env_vars: Optional[List[k8s.V1EnvVar]] = None,
env_from: Optional[List[k8s.V1EnvFromSource]] = None,
secrets: Optional[List[Secret]] = None,
in_cluster: Optional[bool] = None,
cluster_context: Optional[str] = None,
labels: Optional[Dict] = None,
reattach_on_restart: bool = True,
startup_timeout_seconds: int = 120,
get_logs: bool = True,
image_pull_policy: Optional[str] = None,
annotations: Optional[Dict] = None,
resources: Optional[k8s.V1ResourceRequirements] = None,
affinity: Optional[k8s.V1Affinity] = None,
config_file: Optional[str] = None,
node_selectors: Optional[dict] = None,
node_selector: Optional[dict] = None,
image_pull_secrets: Optional[List[k8s.V1LocalObjectReference]] = None,
service_account_name: Optional[str] = None,
is_delete_operator_pod: bool = True,
hostnetwork: bool = False,
tolerations: Optional[List[k8s.V1Toleration]] = None,
security_context: Optional[Dict] = None,
dnspolicy: Optional[str] = None,
schedulername: Optional[str] = None,
full_pod_spec: Optional[k8s.V1Pod] = None,
init_containers: Optional[List[k8s.V1Container]] = None,
log_events_on_failure: bool = False,
do_xcom_push: bool = False,
pod_template_file: Optional[str] = None,
priority_class_name: Optional[str] = None,
pod_runtime_info_envs: Optional[List[k8s.V1EnvVar]] = None,
termination_grace_period: Optional[int] = None,
configmaps: Optional[List[str]] = None,
**kwargs,
) -> None:
if kwargs.get('xcom_push') is not None:
raise AirflowException("'xcom_push' was deprecated, use 'do_xcom_push' instead")
super().__init__(resources=None, **kwargs)
self.do_xcom_push = do_xcom_push
self.image = image
self.namespace = namespace
self.cmds = cmds or []
self.arguments = arguments or []
self.labels = labels or {}
self.startup_timeout_seconds = startup_timeout_seconds
self.env_vars = convert_env_vars(env_vars) if env_vars else []
if pod_runtime_info_envs:
self.env_vars.extend([convert_pod_runtime_info_env(p) for p in pod_runtime_info_envs])
self.env_from = env_from or []
if configmaps:
self.env_from.extend([convert_configmap(c) for c in configmaps])
self.ports = [convert_port(p) for p in ports] if ports else []
self.volume_mounts = [convert_volume_mount(v) for v in volume_mounts] if volume_mounts else []
self.volumes = [convert_volume(volume) for volume in volumes] if volumes else []
self.secrets = secrets or []
self.in_cluster = in_cluster
self.cluster_context = cluster_context
self.reattach_on_restart = reattach_on_restart
self.get_logs = get_logs
self.image_pull_policy = image_pull_policy
if node_selectors:
# Node selectors is incorrect based on k8s API
warnings.warn(
"node_selectors is deprecated. Please use node_selector instead.", DeprecationWarning
)
self.node_selector = node_selectors
elif node_selector:
self.node_selector = node_selector
else:
self.node_selector = {}
self.annotations = annotations or {}
self.affinity = convert_affinity(affinity) if affinity else {}
self.k8s_resources = convert_resources(resources) if resources else {}
self.config_file = config_file
self.image_pull_secrets = convert_image_pull_secrets(image_pull_secrets) if image_pull_secrets else []
self.service_account_name = service_account_name
self.is_delete_operator_pod = is_delete_operator_pod
self.hostnetwork = hostnetwork
self.tolerations = (
[convert_toleration(toleration) for toleration in tolerations] if tolerations else []
)
self.security_context = security_context or {}
self.dnspolicy = dnspolicy
self.schedulername = schedulername
self.full_pod_spec = full_pod_spec
self.init_containers = init_containers or []
self.log_events_on_failure = log_events_on_failure
self.priority_class_name = priority_class_name
self.pod_template_file = pod_template_file
self.name = self._set_name(name)
self.random_name_suffix = random_name_suffix
self.termination_grace_period = termination_grace_period
self.pod_request_obj: Optional[k8s.V1Pod] = None
self.pod: Optional[k8s.V1Pod] = None
def _render_nested_template_fields(
self,
content: Any,
context: 'Context',
jinja_env: "jinja2.Environment",
seen_oids: set,
) -> None:
if id(content) not in seen_oids and isinstance(content, k8s.V1EnvVar):
seen_oids.add(id(content))
self._do_render_template_fields(content, ('value', 'name'), context, jinja_env, seen_oids)
return
super()._render_nested_template_fields(content, context, jinja_env, seen_oids)
@staticmethod
def _get_ti_pod_labels(context: Optional[dict] = None, include_try_number: bool = True) -> dict:
"""
Generate labels for the pod to track the pod in case of Operator crash
:param context: task context provided by airflow DAG
:return: dict
"""
if not context:
return {}
ti = context['ti']
run_id = context['run_id']
labels = {
'dag_id': ti.dag_id,
'task_id': ti.task_id,
'run_id': run_id,
'kubernetes_pod_operator': 'True',
}
# If running on Airflow 2.3+:
map_index = getattr(ti, 'map_index', -1)
if map_index >= 0:
labels['map_index'] = map_index
if include_try_number:
labels.update(try_number=ti.try_number)
# In the case of sub dags this is just useful
if context['dag'].is_subdag:
labels['parent_dag_id'] = context['dag'].parent_dag.dag_id
# Ensure that label is valid for Kube,
# and if not truncate/remove invalid chars and replace with short hash.
for label_id, label in labels.items():
safe_label = pod_generator.make_safe_label_value(str(label))
labels[label_id] = safe_label
return labels
@cached_property
[docs] def pod_manager(self) -> PodManager:
return PodManager(kube_client=self.client)
@cached_property
[docs] def client(self) -> CoreV1Api:
# todo: use airflow Connection / hook to authenticate to the cluster
kwargs: Dict[str, Any] = dict(
cluster_context=self.cluster_context,
config_file=self.config_file,
)
if self.in_cluster is not None:
kwargs.update(in_cluster=self.in_cluster)
return kube_client.get_kube_client(**kwargs)
[docs] def find_pod(self, namespace, context) -> Optional[k8s.V1Pod]:
"""Returns an already-running pod for this task instance if one exists."""
label_selector = self._build_find_pod_label_selector(context)
pod_list = self.client.list_namespaced_pod(
namespace=namespace,
label_selector=label_selector,
).items
pod = None
num_pods = len(pod_list)
if num_pods > 1:
raise AirflowException(f'More than one pod running with labels {label_selector}')
elif num_pods == 1:
pod = pod_list[0]
self.log.info("Found matching pod %s with labels %s", pod.metadata.name, pod.metadata.labels)
self.log.info("`try_number` of task_instance: %s", context['ti'].try_number)
self.log.info("`try_number` of pod: %s", pod.metadata.labels['try_number'])
return pod
[docs] def get_or_create_pod(self, pod_request_obj: k8s.V1Pod, context):
if self.reattach_on_restart:
pod = self.find_pod(self.namespace or pod_request_obj.metadata.namespace, context=context)
if pod:
return pod
self.log.debug("Starting pod:\n%s", yaml.safe_dump(pod_request_obj.to_dict()))
self.pod_manager.create_pod(pod=pod_request_obj)
return pod_request_obj
[docs] def await_pod_start(self, pod):
try:
self.pod_manager.await_pod_start(pod=pod, startup_timeout=self.startup_timeout_seconds)
except PodLaunchFailedException:
if self.log_events_on_failure:
for event in self.pod_manager.read_pod_events(pod).items:
self.log.error("Pod Event: %s - %s", event.reason, event.message)
raise
[docs] def execute(self, context: 'Context'):
remote_pod = None
try:
self.pod_request_obj = self.build_pod_request_obj(context)
self.pod = self.get_or_create_pod( # must set `self.pod` for `on_kill`
pod_request_obj=self.pod_request_obj,
context=context,
)
self.await_pod_start(pod=self.pod)
if self.get_logs:
self.pod_manager.fetch_container_logs(
pod=self.pod,
container_name=self.BASE_CONTAINER_NAME,
follow=True,
)
else:
self.pod_manager.await_container_completion(
pod=self.pod, container_name=self.BASE_CONTAINER_NAME
)
if self.do_xcom_push:
result = self.extract_xcom(pod=self.pod)
remote_pod = self.pod_manager.await_pod_completion(self.pod)
finally:
self.cleanup(
pod=self.pod or self.pod_request_obj,
remote_pod=remote_pod,
)
ti = context['ti']
ti.xcom_push(key='pod_name', value=self.pod.metadata.name)
ti.xcom_push(key='pod_namespace', value=self.pod.metadata.namespace)
if self.do_xcom_push:
return result
[docs] def cleanup(self, pod: k8s.V1Pod, remote_pod: k8s.V1Pod):
pod_phase = remote_pod.status.phase if hasattr(remote_pod, 'status') else None
if not self.is_delete_operator_pod:
with _suppress(Exception):
self.patch_already_checked(pod)
if pod_phase != PodPhase.SUCCEEDED:
if self.log_events_on_failure:
with _suppress(Exception):
for event in self.pod_manager.read_pod_events(pod).items:
self.log.error("Pod Event: %s - %s", event.reason, event.message)
with _suppress(Exception):
self.process_pod_deletion(pod)
error_message = get_container_termination_message(remote_pod, self.BASE_CONTAINER_NAME)
error_message = "\n" + error_message if error_message else ""
raise AirflowException(
f'Pod {pod and pod.metadata.name} returned a failure:{error_message}\n{remote_pod}'
)
else:
with _suppress(Exception):
self.process_pod_deletion(pod)
[docs] def process_pod_deletion(self, pod):
if self.is_delete_operator_pod:
self.log.info("Deleting pod: %s", pod.metadata.name)
self.pod_manager.delete_pod(pod)
else:
self.log.info("skipping deleting pod: %s", pod.metadata.name)
def _build_find_pod_label_selector(self, context: Optional[dict] = None) -> str:
labels = self._get_ti_pod_labels(context, include_try_number=False)
label_strings = [f'{label_id}={label}' for label_id, label in sorted(labels.items())]
return ','.join(label_strings) + f',{self.POD_CHECKED_KEY}!=True,!airflow-worker'
def _set_name(self, name):
if name is None:
if self.pod_template_file or self.full_pod_spec:
return None
raise AirflowException("`name` is required unless `pod_template_file` or `full_pod_spec` is set")
validate_key(name, max_length=220)
return re.sub(r'[^a-z0-9-]+', '-', name.lower())
[docs] def patch_already_checked(self, pod: k8s.V1Pod):
"""Add an "already checked" annotation to ensure we don't reattach on retries"""
pod.metadata.labels[self.POD_CHECKED_KEY] = "True"
body = PodGenerator.serialize_pod(pod)
self.client.patch_namespaced_pod(pod.metadata.name, pod.metadata.namespace, body)
[docs] def on_kill(self) -> None:
if self.pod:
pod = self.pod
kwargs = dict(
name=pod.metadata.name,
namespace=pod.metadata.namespace,
)
if self.termination_grace_period is not None:
kwargs.update(grace_period_seconds=self.termination_grace_period)
self.client.delete_namespaced_pod(**kwargs)
[docs] def build_pod_request_obj(self, context=None):
"""
Returns V1Pod object based on pod template file, full pod spec, and other operator parameters.
The V1Pod attributes are derived (in order of precedence) from operator params, full pod spec, pod
template file.
"""
self.log.debug("Creating pod for KubernetesPodOperator task %s", self.task_id)
if self.pod_template_file:
self.log.debug("Pod template file found, will parse for base pod")
pod_template = pod_generator.PodGenerator.deserialize_model_file(self.pod_template_file)
if self.full_pod_spec:
pod_template = PodGenerator.reconcile_pods(pod_template, self.full_pod_spec)
elif self.full_pod_spec:
pod_template = self.full_pod_spec
else:
pod_template = k8s.V1Pod(metadata=k8s.V1ObjectMeta(name="name"))
pod = k8s.V1Pod(
api_version="v1",
kind="Pod",
metadata=k8s.V1ObjectMeta(
namespace=self.namespace,
labels=self.labels,
name=self.name,
annotations=self.annotations,
),
spec=k8s.V1PodSpec(
node_selector=self.node_selector,
affinity=self.affinity,
tolerations=self.tolerations,
init_containers=self.init_containers,
containers=[
k8s.V1Container(
image=self.image,
name=self.BASE_CONTAINER_NAME,
command=self.cmds,
ports=self.ports,
image_pull_policy=self.image_pull_policy,
resources=self.k8s_resources,
volume_mounts=self.volume_mounts,
args=self.arguments,
env=self.env_vars,
env_from=self.env_from,
)
],
image_pull_secrets=self.image_pull_secrets,
service_account_name=self.service_account_name,
host_network=self.hostnetwork,
security_context=self.security_context,
dns_policy=self.dnspolicy,
scheduler_name=self.schedulername,
restart_policy='Never',
priority_class_name=self.priority_class_name,
volumes=self.volumes,
),
)
pod = PodGenerator.reconcile_pods(pod_template, pod)
if self.random_name_suffix:
pod.metadata.name = PodGenerator.make_unique_pod_id(pod.metadata.name)
for secret in self.secrets:
self.log.debug("Adding secret to task %s", self.task_id)
pod = secret.attach_to_pod(pod)
if self.do_xcom_push:
self.log.debug("Adding xcom sidecar to task %s", self.task_id)
pod = xcom_sidecar.add_xcom_sidecar(pod)
labels = self._get_ti_pod_labels(context)
self.log.info("Creating pod %s with labels: %s", pod.metadata.name, labels)
# Merge Pod Identifying labels with labels passed to operator
pod.metadata.labels.update(labels)
# Add Airflow Version to the label
# And a label to identify that pod is launched by KubernetesPodOperator
pod.metadata.labels.update(
{
'airflow_version': airflow_version.replace('+', '-'),
}
)
pod_mutation_hook(pod)
return pod
[docs] def dry_run(self) -> None:
"""
Prints out the pod definition that would be created by this operator.
Does not include labels specific to the task instance (since there isn't
one in a dry_run) and excludes all empty elements.
"""
pod = self.build_pod_request_obj()
print(yaml.dump(prune_dict(pod.to_dict(), mode='strict')))
class _suppress(AbstractContextManager):
"""
This behaves the same as ``contextlib.suppress`` but logs the suppressed
exceptions as errors with traceback.
The caught exception is also stored on the context manager instance under
attribute ``exception``.
"""
def __init__(self, *exceptions):
self._exceptions = exceptions
self.exception = None
def __enter__(self):
return self
def __exit__(self, exctype, excinst, exctb):
caught_error = exctype is not None and issubclass(exctype, self._exceptions)
if caught_error:
self.exception = excinst
logger = logging.getLogger()
logger.error(str(excinst), exc_info=True)
return caught_error