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Version: 0.29.0

Setting Up Pipelines to Trigger a Tekton Pipeline Enterprise

Using Flux's Notification Controller, a Tekton EventListener can be triggered on Pipeline promotion events.

Configuring Tekton Pipeline

Tekton Tasks

In this tutorial, we have two tasks to demonstrate how to use parameter values from the Pipeline event payload. Both tasks print out messages with information about the pipeline promotion. Each task has three parameters: name, namespace, and message.

---
apiVersion: tekton.dev/v1beta1
kind: Task
metadata:
name: hello
namespace: ww-pipeline
spec:
params:
- name: name
type: string
- name: namespace
type: string
- name: message
type: string
steps:
- name: echo
image: alpine
script: |
#!/bin/sh
echo "Hello $(params.namespace)/$(params.name)!"
echo "Message: $(params.message)"
---
apiVersion: tekton.dev/v1beta1
kind: Task
metadata:
name: goodbye
namespace: ww-pipeline
spec:
params:
- name: name
type: string
- name: namespace
type: string
- name: message
type: string
steps:
- name: goodbye
image: ubuntu
script: |
#!/bin/bash
echo "Goodbye $(params.namespace)/$(params.name)!"
echo "Message: $(params.message)"

Tekton Pipeline

The hello-goodbye Tekton Pipeline has the same three parameters as the tasks and it passes down the values to them.

---
apiVersion: tekton.dev/v1beta1
kind: Pipeline
metadata:
name: hello-goodbye
namespace: ww-pipeline
spec:
params:
- name: name
type: string
- name: namespace
type: string
- name: message
type: string
tasks:
- name: hello
taskRef:
name: hello
params:
- name: namespace
value: $(params.namespace)
- name: name
value: $(params.name)
- name: message
value: $(params.message)
- name: goodbye
runAfter:
- hello
taskRef:
name: goodbye
params:
- name: namespace
value: $(params.namespace)
- name: name
value: $(params.name)
- name: message
value: $(params.message)

Configuring Tekton Pipline Automation

In order to be able to trigger a Pipeline from an external source, we need three Tekton resources.

  1. TriggerBinding: This resource binds the incoming JSON message to parameter variables.
  2. TriggerTemplate: This resource is the template of the PipelineRun that will be started.
  3. EventListener: This resource glues the above two resources together and creates an http listener service.

Tekton TriggerBinding

A JSON payload from the Notification Service about a Pipeline promotion looks like this:

{
"involvedObject": {
"kind": "Pipeline",
"namespace": "flux-system",
"name": "podinfo-pipeline",
"uid": "74d9e3b6-0269-4c12-9051-3ce8cfb7886f",
"apiVersion": "pipelines.weave.works/v1alpha1",
"resourceVersion": "373617"
},
"severity": "info",
"timestamp": "2023-02-08T12:34:13Z",
"message": "Promote pipeline flux-system/podinfo-pipeline to prod with version 6.1.5",
"reason": "Promote",
"reportingController": "pipeline-controller",
"reportingInstance": "chart-pipeline-controller-8549867565-7822g"
}

In our tasks, we are using only the involvedObject.name, involvedObject.namespace and message fields:

---
apiVersion: triggers.tekton.dev/v1beta1
kind: TriggerBinding
metadata:
name: ww-pipeline-binding
namespace: ww-pipeline
spec:
params:
- name: namespace
value: $(body.involvedObject.namespace)
- name: name
value: $(body.involvedObject.name)
- name: message
value: $(body.message)

Tekton TriggerTemplate

The template has the same parameters as the Pipeline resources:

---
apiVersion: triggers.tekton.dev/v1beta1
kind: TriggerTemplate
metadata:
name: ww-pipeline-template
namespace: ww-pipeline
spec:
params:
- name: namespace
default: "Unknown"
- name: name
default: "Unknown"
- name: message
default: "no message"
resourcetemplates:
- apiVersion: tekton.dev/v1beta1
kind: PipelineRun
metadata:
generateName: hello-goodbye-run-
spec:
pipelineRef:
name: hello-goodbye
params:
- name: name
value: $(tt.params.name)
- name: namespace
value: $(tt.params.namespace)
- name: message
value: $(tt.params.message)

Tekton EventListener

To access all required resources, we need an extra service account:

---
apiVersion: v1
kind: ServiceAccount
metadata:
name: tekton-ww-pipeline-robot
namespace: ww-pipeline
---
apiVersion: rbac.authorization.k8s.io/v1
kind: RoleBinding
metadata:
name: triggers-example-eventlistener-binding
namespace: ww-pipeline
subjects:
- kind: ServiceAccount
name: tekton-ww-pipeline-robot
namespace: ww-pipeline
roleRef:
apiGroup: rbac.authorization.k8s.io
kind: ClusterRole
name: tekton-triggers-eventlistener-roles
---
apiVersion: rbac.authorization.k8s.io/v1
kind: ClusterRoleBinding
metadata:
name: triggers-example-eventlistener-clusterbinding
subjects:
- kind: ServiceAccount
name: tekton-ww-pipeline-robot
namespace: ww-pipeline
roleRef:
apiGroup: rbac.authorization.k8s.io
kind: ClusterRole
name: tekton-triggers-eventlistener-clusterroles

With this ServiceAccount, we can create the EventListener using the TriggerBinding and TriggerTemplate:

---
apiVersion: triggers.tekton.dev/v1beta1
kind: EventListener
metadata:
name: ww-pipeline-listener
namespace: ww-pipeline
spec:
serviceAccountName: tekton-ww-pipeline-robot
triggers:
- name: ww-pipeline-trigger
bindings:
- ref: ww-pipeline-binding
template:
ref: ww-pipeline-template

At this point, we should have a Service for our EventListener.

❯ kubectl get service -n ww-pipeline
NAME TYPE CLUSTER-IP EXTERNAL-IP PORT(S) AGE
el-ww-pipeline-listener ClusterIP 10.96.250.23 <none> 8080/TCP,9000/TCP 3d

Configure Notification Provider

In this case, we are using Tekton in the same cluster, so we can use an internal address to access the EventListener service. If they are not in the same cluster, exposing the service may be required through an ingress or a service mesh.

---
apiVersion: notification.toolkit.fluxcd.io/v1beta1
kind: Provider
metadata:
name: tekton-promotion
namespace: hello-podinfo
spec:
type: generic
address: http://el-ww-pipeline-listener.ww-pipeline:8080/

Set Up Alerts

We can configure an Alert to use the tekton-promotion provider. For example, an Alert for the podinfo-pipeline in the flux-system namespace:

---
apiVersion: notification.toolkit.fluxcd.io/v1beta1
kind: Alert
metadata:
name: tekton-promotion-podinfo
namespace: hello-podinfo
spec:
eventSeverity: info
eventSources:
- kind: Pipeline
name: hello-podinfo
namespace: flux-system
providerRef:
name: tekton-promotion