Cloud Event output resource

Define a new type of PipelineResource for cloud events.
This resource can be used as an output only. The resource is only
defined here, it's not functional yet.

Signed-off-by: Andrea Frittoli <andrea.frittoli@uk.ibm.com>

pkg/apis/pipeline/v1alpha1/cloud_event_resource.go

@@ -0,0 +1,98 @@
+/*
+Copyright 2019 The Tekton Authors.
+
+Licensed under the Apache License, Version 2.0 (the "License");
+you may not use this file except in compliance with the License.
+You may obtain a copy of the License at
+
+    http://www.apache.org/licenses/LICENSE-2.0
+
+Unless required by applicable law or agreed to in writing, software
+distributed under the License is distributed on an "AS IS" BASIS,
+WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
+See the License for the specific language governing permissions and
+limitations under the License.
+*/
+
+package v1alpha1
+
+import (
+	"fmt"
+	"strings"
+
+	corev1 "k8s.io/api/core/v1"
+)
+
+// CloudEventResource is an event sink to which events are delivered when a TaskRun has finished
+type CloudEventResource struct {
+	Name      string               `json:"name"`
+	Type      PipelineResourceType `json:"type"`
+	TargetURI string               `json:"targetURI"`
+	Owner     TaskRun              `json:"taskRun"`
+}
+
+// NewCloudEventResource creates a new CloudEvent resource to pass to a Task
+func NewCloudEventResource(r *PipelineResource) (*CloudEventResource, error) {
+	if r.Spec.Type != PipelineResourceTypeCloudEvent {
+		return nil, fmt.Errorf("CloudEventResource: Cannot create a Cloud Event resource from a %s Pipeline Resource", r.Spec.Type)
+	}
+	var targetURI string
+	var targetURISpecified bool
+
+	for _, param := range r.Spec.Params {
+		switch {
+		case strings.EqualFold(param.Name, "TargetURI"):
+			targetURI = param.Value
+			if param.Value != "" {
+				targetURISpecified = true
+			}
+		}
+	}
+
+	if !targetURISpecified {
+		return nil, fmt.Errorf("CloudEventResource: Need URI to be specified in order to create a CloudEvent resource %s", r.Name)
+	}
+	return &CloudEventResource{
+		Name:      r.Name,
+		Type:      r.Spec.Type,
+		TargetURI: targetURI,
+	}, nil
+}
+
+// GetName returns the name of the resource
+func (s CloudEventResource) GetName() string {
+	return s.Name
+}
+
+// GetType returns the type of the resource, in this case "storage"
+func (s CloudEventResource) GetType() PipelineResourceType {
+	return PipelineResourceTypeCloudEvent
+}
+
+// SetOwner sets the owner TaskRun. PipelineResources don't have a proper owner in k8s terms, they may have more than one in theory, so we cannot use the owner reference since there is none defined
+func (s *CloudEventResource) SetOwner(owner TaskRun) {
+	s.Owner = owner
+}
+
+// Replacements is used for template replacement on an CloudEventResource inside of a Taskrun.
+func (s *CloudEventResource) Replacements() map[string]string {
+	return map[string]string{
+		"name":       s.Name,
+		"type":       string(s.Type),
+		"target-uri": s.TargetURI,
+	}
+}
+
+// GetUploadContainerSpec returns nothing as the cloud event is sent by the controller once the POD execution is completed
+func (s *CloudEventResource) GetUploadContainerSpec() ([]corev1.Container, error) {
+	return nil, nil
+}
+
+// GetDownloadContainerSpec returns nothing, cloud events cannot be used as input resource
+func (s *CloudEventResource) GetDownloadContainerSpec() ([]corev1.Container, error) {
+	return nil, nil
+}
+
+// SetDestinationDirectory required by the interface but not really used
+func (s *CloudEventResource) SetDestinationDirectory(path string) {
+}

pkg/apis/pipeline/v1alpha1/resource_types.go

@@ -43,10 +43,13 @@ const (
 
 	// PipelineResourceTypePullRequest indicates that this source is a SCM Pull Request.
 	PipelineResourceTypePullRequest PipelineResourceType = "pullRequest"
+
+	// PipelineResourceTypeCloudEvent indicates that this source is a cloud event URI
+	PipelineResourceTypeCloudEvent PipelineResourceType = "cloudEvent"
 )
 
 // AllResourceTypes can be used for validation to check if a provided Resource type is one of the known types.
-var AllResourceTypes = []PipelineResourceType{PipelineResourceTypeGit, PipelineResourceTypeStorage, PipelineResourceTypeImage, PipelineResourceTypeCluster, PipelineResourceTypePullRequest}
+var AllResourceTypes = []PipelineResourceType{PipelineResourceTypeGit, PipelineResourceTypeStorage, PipelineResourceTypeImage, PipelineResourceTypeCluster, PipelineResourceTypePullRequest, PipelineResourceTypeCloudEvent}
 
 // PipelineResourceInterface interface to be implemented by different PipelineResource types
 type PipelineResourceInterface interface {
@@ -143,6 +146,8 @@ func ResourceFromType(r *PipelineResource) (PipelineResourceInterface, error) {
 		return NewStorageResource(r)
 	case PipelineResourceTypePullRequest:
 		return NewPullRequestResource(r)
+	case PipelineResourceTypeCloudEvent:
+		return NewCloudEventResource(r)
 	}
 	return nil, xerrors.Errorf("%s is an invalid or unimplemented PipelineResource", r.Spec.Type)
 }