A bit of background about template outputs

Argo Workflows supports a number of different types of templates.

Each type of template supports different types of reference within the template.

Within a steps template, you may access the output parameters of other steps with steps.step-name.outputs.parameters.param-name (for named parameters) or steps.step-name.outputs.result (for the stdout of a script or container template).

Example (see full Workflow):

  - name: output-parameter    steps:    - - name: generate-parameter        template: whalesay    - - name: consume-parameter        template: print-message        arguments:          parameters:          - name: message            value: "{{steps.generate-parameter.outputs.parameters.hello-param}}"

Within a dag template, you may access the output of various tasks using a similar syntax, just using tasks. instead of steps..

Example (see full Workflow):

    - name: main      dag:        tasks:          - name: flip-coin            template: flip-coin          - name: heads            depends: flip-coin            template: heads            when: "{{tasks.flip-coin.outputs.result}} == heads"          - name: tails            depends: flip-coin            template: tails            when: "{{tasks.flip-coin.outputs.result}} == tails"

Within a container or script template, you may access only the inputs of that template*. You may not directly access the outputs of steps or tasks from steps or tasks templates from a container or script template.

Referencing a step output from a DAG

As mentioned above, a DAG template cannot directly reference step outputs from a steps template. But a step within a steps template can pass a step output to a DAG template.

In your example, it would look something like this:

  templates:  - name: the-entrypoint    steps:    - - name: step01        template: first-step    - - name: step02        template: second-step    - - name: step03        template: third-step    - - name: step04-the-dag-step        template: fourth-step        arguments:          parameters:          - name: some-param            value: "{{steps.step03.outputs.result}}"  - name: fourth-step    inputs:      parameters:      - name: some-param    dag:      tasks:        # use the input parameter in the fourth-step template with "{{inputs.parameters.some-param}}"

tl;dr

steps. and tasks. variables are meant to be referenced within a single steps- or tasks-template, but they can be explicitly passed between templates. If you need to use the output of a step in a DAG, directly pass that output as an argument where the DAG is invoked.

In your case, the DAG template is invoked as the last of four steps, so that is where you will pass the argument.

_{* Okay, you also have access to various other variables from within a script or container template, but you don't have access to variables that are scoped as internal variables within another template.}