Prerequisites

Adding Triggers to our Application:

Now let’s add a TriggerTemplate, TriggerBinding, and an EventListener to our project.

Trigger Template

A TriggerTemplate is a resource which has parameters that can be substituted anywhere within the resources of template.

The definition of our TriggerTemplate is given in 03-triggers/02-template.yaml.

apiVersion: triggers.tekton.dev/v1alpha1
kind: TriggerTemplate
metadata:
  name: vote-app
spec:
  params:
  - name: git-repo-url
    description: The git repository url
  - name: git-revision
    description: The git revision
    default: master
  - name: git-repo-name
    description: The name of the deployment to be created / patched

  resourcetemplates:
  - apiVersion: tekton.dev/v1alpha1
    kind: PipelineResource
    metadata:
      name: $(params.git-repo-name)-git-repo-$(uid)
    spec:
      type: git
      params:
      - name: revision
        value: $(params.git-revision)
      - name: url
        value: $(params.git-repo-url)

  - apiVersion: tekton.dev/v1alpha1
    kind: PipelineResource
    metadata:
      name: $(params.git-repo-name)-image-$(uid)
    spec:
      type: image
      params:
      - name: url
        value: image-registry.openshift-image-registry.svc:5000/pipelines-tutorial/$(params.git-repo-name):latest

  - apiVersion: tekton.dev/v1beta1
    kind: PipelineRun
    metadata:
      name: build-deploy-$(params.git-repo-name)-$(uid)
    spec:
      serviceAccountName: pipeline
      pipelineRef:
        name: build-and-deploy
      resources:
      - name: git-repo
        resourceRef:
          name: $(params.git-repo-name)-git-repo-$(uid)
      - name: image
        resourceRef:
          name: $(params.git-repo-name)-image-$(uid)
      params:
      - name: deployment-name
        value: $(params.git-repo-name)

• Run the following command to apply Triggertemplate.

oc create -f https://raw.githubusercontent.com/openshift/pipelines-tutorial/master/03_triggers/02_template.yaml

Trigger Binding

TriggerBindings is a map that enables you to capture fields from an event and store them as parameters and replace them in triggerTemplate whenever an event occurs.

The definition of our TriggerBinding is given in 03-triggers/01_binding.yaml.

apiVersion: triggers.tekton.dev/v1alpha1
kind: TriggerBinding
metadata:
  name: vote-app
spec:
  params:
  - name: git-repo-url
    value: $(body.repository.url)
  - name: git-repo-name
    value: $(body.repository.name)
  - name: git-revision
    value: $(body.head_commit.id)

The exact paths (keys) of the parameter we need can be found by examining the event payload (eg: GitHub events).

Run the following command to apply Triggertemplate.

oc create -f https://raw.githubusercontent.com/openshift/pipelines-tutorial/master/03_triggers/01_binding.yaml

Event Listener

This component sets up a Service and listens for events. It also connects a TriggerTemplate to a TriggerBinding, into an addressable endpoint (the event sink)

The definition for our EventListener can be found in 03-triggers/03_event_listener.yaml.

apiVersion: triggers.tekton.dev/v1alpha1
kind: EventListener
metadata:
  name: vote-app
spec:
  serviceAccountName: pipeline
  triggers:
  - bindings:
    - name: vote-app
    template:
      name: vote-app

• Run the following command to create Triggertemplate.

oc create -f https://raw.githubusercontent.com/openshift/pipelines-tutorial/master/03_triggers/03_event_listener.yaml

Note: EventListener will setup a Service. We need to expose that Service as an OpenShift Route to make it publicly accessible.

• Run below command to expose eventlistener service as a route

oc expose svc el-vote-app