无法通过另一个工作流模板将输出参数从一个工作流模板传递到工作流

Question

我有两个工作流程模板generate-output和lib-read-outputs一个工作流程，output-paramter如下所示

1. generate-output.yaml

apiVersion: argoproj.io/v1alpha1
kind: WorkflowTemplate
metadata:
  name: generate-output
spec:
  entrypoint: main
  templates:
    - name: main
      dag:
        tasks:

          # Generate Json for Outputs
          - name: read-outputs
            arguments:
              parameters:
                - name: outdata
                  value: |
                    {
                      "version": 4,
                      "terraform_version": "0.14.11",
                      "serial": 0,
                      "lineage": "732322df-5bd43-6e92-8f46-56c0dddwe83cb4",
                      "outputs": {
                        "key_alias_arn": {
                          "value": "arn:aws:kms:us-west-2:123456789:alias/tetsing-key",
                          "type": "string",
                          "sensitive": true
                        },
                        "key_arn": {
                          "value": "arn:aws:kms:us-west-2:123456789:alias/tetsing-key",
                          "type": "string",
                          "sensitive": true
                        }
                      }
                    }
            template: retrieve-outputs

    # Create Json
    - name: retrieve-outputs
      inputs:
        parameters:
          - name: outdata
      script:
        image: python
        command: [python]
        env:
          - name: OUTDATA
            value: "{{inputs.parameters.outdata}}"
        source: |
          import json
          import os
          OUTDATA = json.loads(os.environ["OUTDATA"])
          with open('/tmp/templates_lst.json', 'w') as outfile:
            outfile.write(str(json.dumps(OUTDATA['outputs'])))
        volumeMounts:
          - name: out
            mountPath: /tmp
      volumes:
        - name: out
          emptyDir: { }
      outputs:
        parameters:
          - name: message
            valueFrom:
              path: /tmp/templates_lst.json

2. lib-read-outputs.yaml

apiVersion: argoproj.io/v1alpha1
kind: WorkflowTemplate
metadata:
  name: lib-read-outputs
spec:
  entrypoint: main
  templates:
    - name: main
      dag:
        tasks:
          # Read Outputs
          - name: lib-wft
            templateRef:
              name: generate-output
              template: main

3. output-paramter.yaml

apiVersion: argoproj.io/v1alpha1
kind: Workflow
metadata:
  generateName: output-paramter-
spec:
  entrypoint: main
  templates:
    - name: main
      dag:
        tasks:
          # Json Output data task1
          - name: wf
            templateRef:
              name: lib-read-outputs
              template: main

          - name: lib-wf2
            dependencies: [wf]
            arguments:
              parameters:
                - name: outputResult
                  value: "{{tasks.wf.outputs.parameters.message}}"
            template: whalesay

    - name: whalesay
      inputs:
        parameters:
          - name: outputResult
      container:
        image: docker/whalesay:latest
        command: [cowsay]
        args: ["{{inputs.parameters.outputResult}}"]

我正在尝试将工作流程模板中生成的输出参数传递给generate-output工作流程output-paramterlib-read-outputs

当我执行它们时，出现以下错误 -Failed: invalid spec: templates.main.tasks.lib-wf2 failed to resolve {{tasks.wf.outputs.parameters.message}}

Answer 1

默认情况下，DAG 和步骤模板不生成输出

即使只有一个子模板，DAG 和步骤模板也不会自动生成其子模板的输出。

例如，no-parameters这里的模板不会产生输出，即使它调用了具有输出的模板。

apiVersion: argoproj.io/v1alpha1
kind: WorkflowTemplate
spec:
  templates:
  - name: no-parameters
    dag:
      tasks:
      - name: get-a-parameter
        template: get-a-parameter

如果您考虑具有多个任务的 DAG 模板，那么缺少输出是有道理的：

apiVersion: argoproj.io/v1alpha1
kind: WorkflowTemplate
spec:
  templates:
  - name: no-parameters
    dag:
      tasks:
      - name: get-a-parameter
        template: get-a-parameter
      - name: get-another-parameter
        depends: get-a-parameter
        template: get-another-parameter

应该产生哪个任务的输出no-parameters？由于尚不清楚，DAG 和步骤模板默认情况下不会生成输出。

您可以将模板视为函数。您不会期望函数隐式返回其调用的函数的输出。

def get_a_string():
    return "Hello, world!"

def call_get_a_string():
    get_a_string()

print(call_get_a_string())  # This prints nothing.

但 DAG 或步骤模板可以转发输出

您可以通过设置 DAG 或步骤模板的字段来转发输出outputs。

apiVersion: argoproj.io/v1alpha1
kind: WorkflowTemplate
metadata:
  name: get-parameters-wftmpl
spec:
  templates:
  - name: get-parameters
    dag:
      tasks:
      - name: get-a-parameter
        template: get-a-parameter
      - name: get-another-parameter
        depends: get-a-parameter
        template: get-another-parameter
    # This is the critical part!
    outputs:
      parameters:
      - name: parameter-1
        valueFrom: 
          expression: "tasks['get-a-parameter'].outputs.parameters['parameter-name']"
      - name: parameter-2
        valueFrom: 
          expression: "tasks['get-another-parameter'].outputs.parameters['parameter-name']"
---
apiVersion: argoproj.io/v1alpha1
kind: Workflow
spec:
  templates:
  - name: print-parameter
    dag:
      tasks:
      - name: get-parameters
        templateRef:
          name: get-parameters-wftmpl
          template: get-parameters 
      - name: print-parameter
        depends: get-parameters
        template: print-parameter
        arguments:
          parameters:
          - name: parameter
            value: "{{tasks.get-parameters.outputs.parameters.parameter-1}}"

继续Python的类比：

def get_a_string():
    return "Hello, world!"

def call_get_a_string():
    return get_a_string()  # Add 'return'.

print(call_get_a_string())  # This prints "Hello, world!".

所以，根据你的具体情况...

1. 在 WorkflowTemplate中的模板中添加一个outputs部分，以转发模板中的输出参数。maingenerate-parameterretrieve-parameters

   apiVersion: argoproj.io/v1alpha1
   kind: WorkflowTemplate
   metadata:
     name: generate-parameter
   spec:
     entrypoint: main
     templates:
       - name: main
         outputs:
           parameters:
             - name: message
               valueFrom: 
                 expression: "tasks['read-parameters'].outputs.parameters.message"
         dag:
           tasks:
             # ... the rest of the file ...
   
   

2. 将一个outputs部分添加到WorkflowTemplatemain中的模板lib-read-parameters以转发的generate-parameter参数。

   apiVersion: argoproj.io/v1alpha1
   kind: WorkflowTemplate
   metadata:
     name: lib-read-parameters
   spec:
     entrypoint: main
     templates:
       - name: main
         outputs:
           parameters:
             - name: message
               valueFrom:
                 expression: "tasks['lib-wft'].outputs.parameters.message"
         dag:
           tasks:
             # ... the rest of the file ...