Allow creating v1beta1 resources

Fixes tektoncd#481

Signed-off-by: Dibyo Mukherjee <dibyo@google.com>

examples/v1beta1/README.md

@@ -0,0 +1,47 @@
+## V1Beta1 Task EventListener
+
+Creates an EventListener that creates a v1beta1 TaskRun.
+
+### Try it out locally:
+
+1. Create the service account:
+
+   ```shell script
+   kubectl apply -f examples/role-resources/triggerbinding-roles
+   kubectl apply -f examples/role-resources/
+   ```
+
+1. Create the V1Beta1 EventListener:
+
+   ```shell script
+   kubectl apply -f examples/v1beta1/v1beta1-listener.yaml
+   ```
+
+1. Port forward:
+
+   ```shell script
+   kubectl port-forward \
+    "$(kubectl get pod --selector=eventlistener=v1beta1-listener -oname)" \
+     8080
+   ```
+
+   **Note**: Instead of port forwarding, you can set the
+   [`serviceType`](https://github.com/tektoncd/triggers/blob/master/docs/eventlisteners.md#serviceType)
+   to `LoadBalancer` to expose the EventListener with a public IP.
+
+1. Test by sending the sample payload.
+
+   ```shell script
+   curl -v \
+   -H 'Content-Type: application/json' \
+   --data "{}" \
+   http://localhost:8080
+   ```
+
+   The response status code should be `201 Created`
+
+1. You should see a new TaskRun that got created:
+
+   ```shell script
+   kubectl get taskruns | grep v1beta1-run-
+   ```

examples/v1beta1/v1beta1-listener.yaml

@@ -0,0 +1,29 @@
+---
+apiVersion: tekton.dev/v1alpha1
+kind: TriggerTemplate
+metadata:
+  name: v1beta1-task-template
+spec:
+  resourcetemplates:
+  - apiVersion: tekton.dev/v1beta1
+    kind: TaskRun
+    metadata:
+      generateName: v1beta1-run-
+    spec:
+      taskSpec:
+        steps:
+        - name: "hellothere"
+          image: ubuntu
+          script: echo "hello there"
+---
+apiVersion: tekton.dev/v1alpha1
+kind: EventListener
+metadata:
+  name: v1beta1-task-listener
+spec:
+  # from examples/role-resources/servicaccount.yaml
+  serviceAccountName: tekton-triggers-example-sa
+  triggers:
+    - name: v1beta1-task-trigger
+      template:
+        name: v1beta1-task-template

pkg/apis/triggers/v1alpha1/trigger_template_types.go

@@ -17,7 +17,8 @@ limitations under the License.
 package v1alpha1
 
 import (
-	pipelinev1 "github.com/tektoncd/pipeline/pkg/apis/pipeline/v1alpha1"
+	pipelinev1alpha1 "github.com/tektoncd/pipeline/pkg/apis/pipeline/v1alpha1"
+	pipelinev1beta1 "github.com/tektoncd/pipeline/pkg/apis/pipeline/v1beta1"
 	metav1 "k8s.io/apimachinery/pkg/apis/meta/v1"
 	"k8s.io/apimachinery/pkg/runtime"
 	"k8s.io/apimachinery/pkg/runtime/serializer"
@@ -33,15 +34,19 @@ var Decoder runtime.Decoder
 
 func init() {
 	scheme := runtime.NewScheme()
-	utilruntime.Must(pipelinev1.AddToScheme(scheme))
+	utilruntime.Must(pipelinev1alpha1.AddToScheme(scheme))
+	utilruntime.Must(pipelinev1beta1.AddToScheme(scheme))
 	codec := serializer.NewCodecFactory(scheme)
-	Decoder = codec.UniversalDecoder(pipelinev1.SchemeGroupVersion)
+	Decoder = codec.UniversalDecoder(
+		pipelinev1alpha1.SchemeGroupVersion,
+		pipelinev1beta1.SchemeGroupVersion,
+	)
 }
 
 // TriggerTemplateSpec holds the desired state of TriggerTemplate
 type TriggerTemplateSpec struct {
-	Params            []pipelinev1.ParamSpec    `json:"params,omitempty"`
-	ResourceTemplates []TriggerResourceTemplate `json:"resourcetemplates,omitempty"`
+	Params            []pipelinev1alpha1.ParamSpec `json:"params,omitempty"`
+	ResourceTemplates []TriggerResourceTemplate    `json:"resourcetemplates,omitempty"`
 }
 
 // TriggerResourceTemplate describes a resource to create

pkg/apis/triggers/v1alpha1/trigger_template_validation_test.go

@@ -32,6 +32,9 @@ import (
 var simpleResourceTemplate = runtime.RawExtension{
 	Raw: []byte(`{"kind":"PipelineRun","apiVersion":"tekton.dev/v1alpha1","metadata":{"creationTimestamp":null},"spec":{},"status":{}}`),
 }
+var v1beta1ResourceTemplate = runtime.RawExtension{
+	Raw: []byte(`{"kind":"PipelineRun","apiVersion":"tekton.dev/v1beta1","metadata":{"creationTimestamp":null},"spec":{},"status":{}}`),
+}
 var paramResourceTemplate = runtime.RawExtension{
 	Raw: []byte(`{"kind":"PipelineRun","apiVersion":"tekton.dev/v1alpha1","metadata":{"creationTimestamp":null},"spec": "$(params.foo)","status":{}}`),
 }
@@ -70,6 +73,12 @@ func TestTriggerTemplate_Validate(t *testing.T) {
 				b.TriggerTemplateParam("foo", "desc", "val"),
 				b.TriggerResourceTemplate(simpleResourceTemplate))),
 			want: nil,
+		}, {
+			name: "valid v1beta1 template",
+			template: b.TriggerTemplate("tt", "foo", b.TriggerTemplateSpec(
+				b.TriggerTemplateParam("foo", "desc", "val"),
+				b.TriggerResourceTemplate(v1beta1ResourceTemplate))),
+			want: nil,
 		}, {
 			name: "missing resource template",
 			template: b.TriggerTemplate("tt", "foo", b.TriggerTemplateSpec(