Output Parameters¶
Output parameters provide a general mechanism to use the result of a step as a parameter rather than as an artifact. This allows you to use the result from any type of step, not just a script
, for conditional tests, loops, and arguments. Output parameters work similarly to script result
except that the value of the output parameter is set to the contents of a generated file rather than the contents of stdout
.
apiVersion: argoproj.io/v1alpha1
kind: Workflow
metadata:
generateName: output-parameter-
spec:
entrypoint: output-parameter
templates:
- name: output-parameter
steps:
- - name: generate-parameter
template: whalesay
- - name: consume-parameter
template: print-message
arguments:
parameters:
# Pass the hello-param output from the generate-parameter step as the message input to print-message
- name: message
value: "{{steps.generate-parameter.outputs.parameters.hello-param}}"
- name: whalesay
container:
image: docker/whalesay:latest
command: [sh, -c]
args: ["echo -n hello world > /tmp/hello_world.txt"] # generate the content of hello_world.txt
outputs:
parameters:
- name: hello-param # name of output parameter
valueFrom:
path: /tmp/hello_world.txt # set the value of hello-param to the contents of this hello-world.txt
- name: print-message
inputs:
parameters:
- name: message
container:
image: docker/whalesay:latest
command: [cowsay]
args: ["{{inputs.parameters.message}}"]
DAG templates use the tasks prefix to refer to another task, for example {{tasks.generate-parameter.outputs.parameters.hello-param}}
.