# This workflow illustrates the use of DAG "targets". Targets can be thought of similarly to make
# targets. If specified, only a subset of the DAG tasks will be executed, just the tasks necessary
# to reach the target(s). For example, given the following DAG workflow, specifying a dag.target of
# 'E' will result in the execution of A, C, and E, while skipping execution of B and D.
#
#    DAG          Executed
#     A              A
#    / \              \
#   B   C              C
#    \ / \              \
#     D   E              E
#
apiVersion: argoproj.io/v1alpha1
kind: Workflow
metadata:
  generateName: dag-target-
spec:
  entrypoint: dag-target
  arguments:
    parameters:
    - name: target
      value: E

  templates:
  - name: dag-target
    dag:
      # dag.target can optionally be specified to restrict the execution of the workflow to only the
      # dependant chain of tasks to reach the desired target. Multiple targets can be specified, as
      # space delimited targets, and can be parameterized. An empty/omitted target will execute all
      # tasks. Submit this example again with different values for target to see how it affects the
      # execution:
      # argo submit dag-targets.yaml -p target="B E"
      target: "{{workflow.parameters.target}}"

      tasks:
      - name: A
        template: echo
        arguments:
          parameters: [{name: message, value: A}]
      - name: B
        dependencies: [A]
        template: echo
        arguments:
          parameters: [{name: message, value: B}]
      - name: C
        dependencies: [A]
        template: echo
        arguments:
          parameters: [{name: message, value: C}]
      - name: D
        dependencies: [B, C]
        template: echo
        arguments:
          parameters: [{name: message, value: D}]
      - name: E
        dependencies: [C]
        template: echo
        arguments:
          parameters: [{name: message, value: E}]

  - name: echo
    inputs:
      parameters:
      - name: message
    container:
      image: alpine:3.7
      command: [echo, "{{inputs.parameters.message}}"]