dag-diamond-steps.yaml

# The following workflow executes a diamond workflow, with each
# node comprising of three parallel fan-in fan-out steps.
# 
#           *
#         / | \
#       A1 A2  A3
#         \ | /
#           *
#         /   \ 
#       /       \
#      *         *
#    / | \     / | \
#  B1  B2 B3  C1 C2 C3
#    \ | /     \ | /
#      *         *
#       \       /
#         \   /
#           *
#         / | \
#       D1 D2  D3
#         \ | /
#           *
apiVersion: argoproj.io/v1alpha1
kind: Workflow
metadata:
  generateName: dag-diamond-steps-
spec:
  entrypoint: diamond
  templates:
  - name: echo
    inputs:
      parameters:
      - name: message
    container:
      image: alpine:3.7
      command: [echo, "{{inputs.parameters.message}}"]
  - name: echo-thrice
    inputs:
      parameters:
      - name: message
    steps:
    - - name: echo
        template: echo
        arguments:
          parameters:
          - {name: message, value: "{{inputs.parameters.message}}{{item}}"}
        withItems: [1,2,3]
  - name: diamond
    dag:
      tasks:
      - name: A
        template: echo-thrice
        arguments:
          parameters: [{name: message, value: A}]
      - name: B
        depends: "A"
        template: echo-thrice
        arguments:
          parameters: [{name: message, value: B}]
      - name: C
        depends: "A"
        template: echo-thrice
        arguments:
          parameters: [{name: message, value: C}]
      - name: D
        depends: "B && C"
        template: echo-thrice
        arguments:
          parameters: [{name: message, value: D}]