kubevela/docs/examples/workflow/app-with-if

Steps with if

Every step can specify a if, you can use the if to determine whether the step should be executed or not.

Always

If you want to execute the step no matter what, for example, send a notification after the component is deployed even it's failed, you can use the if with the value always like:

apiVersion: core.oam.dev/v1beta1
kind: Application
metadata:
  name: if-always-with-err
  namespace: default
spec:
  components:
  - name: err-component
    type: k8s-objects
    properties:
      objects:
        - err: "error case"
  workflow:
    steps:
    - name: apply-err-comp
      type: apply-component
      properties:
        component: err-component
    - name: notification
      type: notification
      if: always
      properties:
        slack:
          url:
            value: <your slack webhook url>
          message:
            text: always

Custom Judgement

You can also write your own judgement logic to determine whether the step should be executed or not, note that the values of if will be executed as cue code. We support some built-in variables to use in if, they are:

• status: in this value, you can get the status of the step for judgement like status.<step-name>.phase == "succeeded", or you can use the simplify way status.<step-name>.succeeded.
• inputs: in this value, you can get the inputs of the step for judgement like inputs.<input-name> == "value".

Status Example

If you want to control the step by the status of another step, you can follow the example:

apiVersion: core.oam.dev/v1beta1
kind: Application
metadata:
  name: if-timeout
  namespace: default
spec:
  components:
  - name: comp-custom-timeout
    type: webservice
    properties:
      image: crccheck/hello-world
      port: 8000
  workflow:
    steps:
    - name: suspend
      timeout: 5s
      type: suspend
    - name: suspend2
      # or `status.suspend.reason == "Timeout"`
      if: status.suspend.timeout
      type: suspend
      timeout: 5s
    - name: notification-1
      type: notification
      if: suspend.timeout
      properties:
        slack:
          url:
            value: <your slack webhook url>
          message:
            text: suspend is timeout
    - name: notification-2
      type: notification
      if: status["notification-1"].succeeded
      properties:
        slack:
          url:
            value: <your slack webhook url>
          message:
            text: notification-1 is succeeded

Inputs example

If you want to control the step by the inputs of another step, you can follow the example:

apiVersion: core.oam.dev/v1beta1
kind: Application
metadata:
  name: if-input
  namespace: default
spec:
  components:
  - name: comp-custom-timeout
    type: webservice
    properties:
      image: crccheck/hello-world
      port: 8000
  workflow:
    steps:
    - name: suspend
      type: suspend
      timeout: 5s
      outputs:
        - name: test
          valueFrom: context.name + " message"
    - name: notification
      type: notification
      inputs:
        - from: test
          parameterKey: slack.message.text
      if: inputs.test == "if-input message"
      properties:
        slack:
          url:
            value: <your slack webhook url>
          message:
            text: from input