Tanzu Supply Chains Minimal Component Example¶

The example below is a hello world component that does not have any input/outputs, only a single variable to print inside the container.

The raw yaml can be found here.

Component definition¶

The variable who-dis is passed from the workload into the Component, to the Pipeline and finally the Task. At execution time the WorkloadRun will create a Stage for each Component. The Stage will create Resumptions and PipelineRuns, with the PipelineRun creating TaskRuns.

Whilst the Task could be written inline inside the pipeline, externalising it enables testing of the Task separately if needed.

component.yaml

---
apiVersion: supply-chain.apps.tanzu.vmware.com/v1alpha1
kind: Component
metadata:
  labels:
    supply-chain.apps.tanzu.vmware.com/catalog: hello-component
  name: hello-0.0.1
spec:
  config:
  - path: spec.who-dis
    schema:
      type: object
      properties:
        name:
          type: string
          description: String input to be printed after "Hello "
          example: bob
      required:
        - name
  description: Outputs hello <who-dis>
  pipelineRun:
    params:
    - name: who-dis
      value: $(workload.spec.who-dis.name)
    pipelineRef:
      name: hello-pipeline
    taskRunTemplate:
      podTemplate:
        securityContext:
          fsGroup: 1000
          runAsGroup: 1000
          runAsUser: 1001
---
apiVersion: tekton.dev/v1
kind: Pipeline
metadata:
  name: hello-pipeline
spec:
  params:
  - description: Input string
    name: who-dis
    type: string
  tasks:
    - name: hello-there
      params:
      - name: who-dis
        value: $(params.who-dis)
      taskRef:
        name: hello-task
---
apiVersion: tekton.dev/v1
kind: Task
metadata:
  name: hello-task
spec:
  params:
  - name: who-dis
    type: string
  steps:
    - name: echo
      image: alpine
      script: |
        #!/bin/sh
        set -e
        echo "Hello $(params.who-dis)"

kubectl apply -f component.yaml

Supply Chain Spec¶

The following yaml creates a supply chain against the component.

supply-chain.yaml

apiVersion: supply-chain.apps.tanzu.vmware.com/v1alpha1
kind: SupplyChain
metadata:
  name: hello.example.tanzu-0.0.1
spec:
  defines: # Describes the workload
    kind: HelloApp
    plural: helloapps
    group: example.tanzu
    version: v1alpha1
  stages: # Describes the stages
    - name: hello
      componentRef: # References the components
        name: hello-0.0.1

Create and check the supply chain is ready.

kubectl apply -f supply-chain.yaml
kubectl get supplychain hello.example.tanzu-0.0.1

Workload Spec¶

The spec of a workload can be generated using the following command.

tanzu workload generate <planned worklaod name> -k <spec.defines.plural>.<spec.defines.group>
tanzu workload generate hello-fred -k helloapps.example.tanzu

The following yaml creates a workload against the supply chain:

workload.yaml

apiVersion: example.tanzu/v1alpha1
kind: HelloApp
metadata:
  name: hello-fred
spec:
  who-dis:
    name: fred

Running the workload¶

This example will deploy everything into the same namespace for simplicity. Under normal operations the supply chain and workload would be deployed into separate namespaces.

Apply the workload.

tanzu workload create -f workload.yaml

Query its state.

tanzu workload get hello-fred

This will automatically trigger a workload run which can be monitored with the following commands. If the supply chain has inputs/outputs they can be queried here under status.stages using kubectl.

tanzu workload run get $(kubectl get helloappruns.example.tanzu \
  -o jsonpath='{.items[0].metadata.name}')

kubectl describe helloappruns.example.tanzu

kubectl get helloappruns.example.tanzu -o yaml

Debugging¶

From TAP 1.9 the components will run in the supply chain namespace, which will be separate from the workload namespace. Under normal operation this will prevent the end user from querying Tekton resources and pods of the stages in the supply chain namespace for security reasons. If the end user needs to see workload run logs they can use the following command:

tanzu workload logs hello-fred

The output of the command can be limited using the following syntax:

tanzu workload logs NAME --since 1h
tanzu workload logs NAME --since 1h --namespace default --run runname

Advanced debugging¶

With access to the supply chain namespace the following commands are available.

kubectl get stage
kubectl tree stage <stage-name>
kubectl get/describe pipeline
kubectl get/describe pipelinerun
kubectl get/describe task
kubectl get/describe taskrun