Argo工作流程中的动态“检入”

时间:2020-03-06 17:59:44

标签: kubernetes workflow directed-acyclic-graphs argo-workflows

Argo允许根据先前步骤的输出动态生成并行工作流步骤。

此处提供了这种动态工作流生成的示例:https://github.com/argoproj/argo/blob/master/examples/loops-param-result.yaml

我正在尝试使用最后的“扇入”步骤创建一个类似的工作流程,该步骤将从动态创建的并行步骤读取输出。这是一个刺路:

apiVersion: argoproj.io/v1alpha1
kind: Workflow
metadata:
  generateName: loops-param-result-
spec:
  entrypoint: loop-param-result-example
  templates:
  - name: loop-param-result-example
    steps:
    - - name: generate
        template: gen-number-list
    - - name: write
        template: output-number
        arguments:
          parameters:
          - name: number
            value: "{{item}}"
        withParam: "{{steps.generate.outputs.result}}"
    - - name: fan-in
        template: fan-in
        arguments:
          parameters:
          - name: numbers
            value: "{{steps.write.outputs.parameters.number}}"

  - name: gen-number-list
    script:
      image: python:alpine3.6
      command: [python]
      source: |
        import json
        import sys
        json.dump([i for i in range(20, 31)], sys.stdout)

  - name: output-number
    inputs:
      parameters:
      - name: number
    container:
      image: alpine:latest
      command: [sh, -c]
      args: ["echo {{inputs.parameters.number}} > /tmp/number.txt"]
    outputs:
      parameters:
        - name: number
          valueFrom:
            path: /tmp/number.txt

  - name: fan-in
    inputs:
      parameters:
        - name: numbers
    container:
      image: alpine:latest
      command: [sh, -c]
      args: ["echo received {{inputs.parameters.numbers}}"]

我能够提交此工作流程,并且该流程成功运行。不幸的是,最后一个fan-in步骤的输出如下所示:

fan-in: received {{steps.write.outputs.parameters.number}}

未对输入numbers的值进行插值。关于如何使它正常工作的任何想法?

1 个答案:

答案 0 :(得分:3)

可通过steps.STEP-NAME.outputs.parameters访问汇总的步骤输出参数。无法通过名称访问一个参数的一组汇总输出。

对工作流程的这一细微更改应该为您提供所需的东西:

apiVersion: argoproj.io/v1alpha1
kind: Workflow
metadata:
  generateName: loops-param-result-
spec:
  entrypoint: loop-param-result-example
  templates:
  - name: loop-param-result-example
    steps:
    - - name: generate
        template: gen-number-list
    - - name: write
        template: output-number
        arguments:
          parameters:
          - name: number
            value: "{{item}}"
        withParam: "{{steps.generate.outputs.result}}"
    - - name: fan-in
        template: fan-in
        arguments:
          parameters:
          - name: numbers
            value: "{{steps.write.outputs.parameters}}"

  - name: gen-number-list
    script:
      image: python:alpine3.6
      command: [python]
      source: |
        import json
        import sys
        json.dump([i for i in range(20, 31)], sys.stdout)

  - name: output-number
    inputs:
      parameters:
      - name: number
    container:
      image: alpine:latest
      command: [sh, -c]
      args: ["echo {{inputs.parameters.number}} > /tmp/number.txt"]
    outputs:
      parameters:
        - name: number
          valueFrom:
            path: /tmp/number.txt

  - name: fan-in
    inputs:
      parameters:
        - name: numbers
    container:
      image: alpine:latest
      command: [sh, -c]
      args: ["echo received {{inputs.parameters.numbers}}"]

唯一的变化是从.number中删除了{{steps.write.outputs.parameters.number}}

这是新的输出:

received [{number:20},{number:21},{number:22},{number:23},{number:24},{number:25},{number:26},{number:27},{number:28},{number:29},{number:30}]

这里是GitHub issue where output parameter aggregation was discussed/created

我放入了enhancement proposal,用于按名称访问汇总的输出参数。