Source code for airflow.providers.cncf.kubernetes.utils.xcom_sidecar

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"""
This module handles all xcom functionality for the KubernetesPodOperator
by attaching a sidecar container that blocks the pod from completing until
Airflow has pulled result data into the worker for xcom serialization.
"""
import copy

from kubernetes.client import models as k8s


[docs]class PodDefaults:
    """Static defaults for Pods"""

[docs]    XCOM_MOUNT_PATH = '/airflow/xcom'
[docs]    SIDECAR_CONTAINER_NAME = 'airflow-xcom-sidecar'
[docs]    XCOM_CMD = 'trap "exit 0" INT; while true; do sleep 1; done;'
[docs]    VOLUME_MOUNT = k8s.V1VolumeMount(name='xcom', mount_path=XCOM_MOUNT_PATH)
[docs]    VOLUME = k8s.V1Volume(name='xcom', empty_dir=k8s.V1EmptyDirVolumeSource())
[docs]    SIDECAR_CONTAINER = k8s.V1Container(
        name=SIDECAR_CONTAINER_NAME,
        command=['sh', '-c', XCOM_CMD],
        image='alpine',
        volume_mounts=[VOLUME_MOUNT],
        resources=k8s.V1ResourceRequirements(
            requests={
                "cpu": "1m",
            }
        ),
    )


[docs]def add_xcom_sidecar(pod: k8s.V1Pod) -> k8s.V1Pod:
    """Adds sidecar"""
    pod_cp = copy.deepcopy(pod)
    pod_cp.spec.volumes = pod.spec.volumes or []
    pod_cp.spec.volumes.insert(0, PodDefaults.VOLUME)
    pod_cp.spec.containers[0].volume_mounts = pod_cp.spec.containers[0].volume_mounts or []
    pod_cp.spec.containers[0].volume_mounts.insert(0, PodDefaults.VOLUME_MOUNT)
    pod_cp.spec.containers.append(PodDefaults.SIDECAR_CONTAINER)

    return pod_cp