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Create Volume For Workflow

This example reuses a volume across scripts.

This avoids the performance loss of upload/download to your artifact storage. Settings a Volume on the Workflow automatically creates a volumeClaimTemplate for the tasks to use.

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from typing import Annotated

from hera.workflows import (
    Artifact,
    NoneArchiveStrategy,
    Parameter,
    RunnerScriptConstructor,
    Steps,
    Workflow,
    models as m,
    script,
)
from hera.workflows.artifact import ArtifactLoader
from hera.workflows.volume import Volume


@script(
    constructor=RunnerScriptConstructor(outputs_directory="/mnt/here"),
    volume_mounts=[
        m.VolumeMount(name="my-vol", mount_path="/mnt/here")
    ],  # We mount the volume created by the Workflow
)
def output_artifact_existing_vol(
    a_number: Annotated[int, Parameter(name="a_number")],
) -> Annotated[int, Artifact(name="successor_out", archive=NoneArchiveStrategy())]:
    return a_number + 1


@script(
    constructor=RunnerScriptConstructor(),
    volume_mounts=[
        m.VolumeMount(name="my-vol", mount_path="/mnt/here")
    ],  # We mount the volume created by the Workflow
)
def use_artifact_existing_vol(
    successor_in: Annotated[
        int, Artifact(name="successor_in", path="/mnt/here/artifacts/successor_out", loader=ArtifactLoader.json)
    ],
):
    print(successor_in)


with Workflow(
    generate_name="create-volume-for-workflow-",
    entrypoint="my-steps",
    volumes=[Volume(name="my-vol", size="1Gi")],  # Creates a VolumeClaimTemplate (and thus the Volume itself)
) as w:
    with Steps(name="my-steps") as s:
        output_task = output_artifact_existing_vol(arguments={"a_number": 3})
        use_artifact_existing_vol(arguments={"successor_in": output_task.get_artifact("successor_out")})

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apiVersion: argoproj.io/v1alpha1
kind: Workflow
metadata:
  generateName: create-volume-for-workflow-
spec:
  entrypoint: my-steps
  templates:
  - name: my-steps
    steps:
    - - name: output-artifact-existing-vol
        template: output-artifact-existing-vol
        arguments:
          parameters:
          - name: a_number
            value: '3'
    - - name: use-artifact-existing-vol
        template: use-artifact-existing-vol
        arguments:
          artifacts:
          - name: successor_in
            from: '{{steps.output-artifact-existing-vol.outputs.artifacts.successor_out}}'
  - name: output-artifact-existing-vol
    inputs:
      parameters:
      - name: a_number
    outputs:
      artifacts:
      - name: successor_out
        path: /mnt/here/artifacts/successor_out
        archive:
          none: {}
    script:
      image: python:3.10
      source: '{{inputs.parameters}}'
      args:
      - -m
      - hera.workflows.runner
      - -e
      - examples.workflows.artifacts.create_volume_for_workflow:output_artifact_existing_vol
      command:
      - python
      env:
      - name: hera__outputs_directory
        value: /mnt/here
      volumeMounts:
      - name: my-vol
        mountPath: /mnt/here
  - name: use-artifact-existing-vol
    inputs:
      artifacts:
      - name: successor_in
        path: /mnt/here/artifacts/successor_out
    script:
      image: python:3.10
      source: '{{inputs.parameters}}'
      args:
      - -m
      - hera.workflows.runner
      - -e
      - examples.workflows.artifacts.create_volume_for_workflow:use_artifact_existing_vol
      command:
      - python
      volumeMounts:
      - name: my-vol
        mountPath: /mnt/here
  volumeClaimTemplates:
  - metadata:
      name: my-vol
    spec:
      accessModes:
      - ReadWriteOnce
      resources:
        requests:
          storage: 1Gi

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