Argo Workflows: Input Parameters in a WorkflowTemplate

argo workflows input parameters template

2 min read | by Jordi Prats

Having a WorkflowTemplate with input parameters in Argo Workflows allows you to create reusable templates that can be customized at runtime. This is useful when you want to pass dynamic values to the workflow template when you submit it.

Following the example of the WorkflowTemplate that builds and pushes a Docker image using Kaniko, we are going to update it to use input parameters.

Here's how you can modify your WorkflowTemplate to use input parameters for --dockerfile, --context and --destination:

apiVersion: argoproj.io/v1alpha1 kind: WorkflowTemplate metadata:  name: build-and-push-image-with-inputs spec:  entrypoint: kaniko-build  volumes:  - name: kaniko-secret  secret:  secretName: dockerhub-registry  items:  - key: .dockerconfigjson  path: config.json  arguments:  parameters:  - name: git-repo-url  - name: image-destination  - name: dockerfile  value: "Dockerfile"   templates:  - name: kaniko-build  inputs:  parameters:  - name: git-repo-url  - name: image-destination  - name: dockerfile  container:  image: gcr.io/kaniko-project/executor:latest  args:  - --dockerfile={{inputs.parameters.dockerfile}}  - --context={{inputs.parameters.git-repo-url}}  - --destination={{inputs.parameters.image-destination}}  volumeMounts:  - name: kaniko-secret  mountPath: "/kaniko/.docker"

Input parameters for this workflow:

  • git-repo-url and image-destination don't have default values, so it becomes mandatory to supply that parameter when you submit the workflow. If you don't, the workflow will fail with an error indicating that the required parameter is missing.
  • dockerfile: Has a default value, so we can override it in the Workflow submission if needed.

To create a Workflow from this template, you can set the parameters as follows:

apiVersion: argoproj.io/v1alpha1 kind: Workflow metadata:  generateName: build-and-push-image- spec:  workflowTemplateRef:  name: build-and-push-image-with-inputs  arguments:  parameters:  - name: git-repo-url  value: "git://github.com/jordiprats/flask-pet2cattle.git#refs/heads/master"  - name: image-destination  value: "jordiprats/ampa:kaniko"

This will use the provided values for git-repo-url and image-destination, while keeping the default value for dockerfile:

$ kubectl apply -f kaniko-template-input.yaml workflowtemplate.argoproj.io/build-and-push-image-with-inputs created $ kubectl create -f kaniko-template-input-instance.yaml ; kubectl get workflow -w workflow.argoproj.io/build-and-push-image-hqnkn created NAME STATUS AGE MESSAGE build-and-push-image-hqnkn build-and-push-image-hqnkn Running 1s build-and-push-image-hqnkn Running 10s build-and-push-image-hqnkn Succeeded 49s

Posted on 28/10/2024

Categories