Add Description and Default fields to TaskParams

This commit adds the `Description` and `Default` fields to the
TaskParams object. Description is a mandatory field to be used for
describing what the Param is. Default is optional, and may be used to
specify a default value for the param.

Adding these fields will make the pipeline easier to understand.

Also fixes a bug in `resources.AddInputResources` where if the Task has
Inputs defined, AddInputResources assumes there *must* be one of type
GitResource, which is not necessarily the case.

Fixes tektoncd#190

examples/build_task.yaml

@@ -10,6 +10,7 @@ spec:
               type: git
         params:
             - name: pathToDockerFile
+              description: The path to the dockerfile to build
     outputs:
         resources:
             - name: builtImage

examples/deploy_tasks.yaml

@@ -10,8 +10,11 @@ spec:
                 type: git
         params:
             - name: pathToHelmCharts
+              description: Path to where the Helm charts live
             - name: helmArgs
+              description: Extra arguments to pass to Helm
             - name: image
+              desription: The image to override the Helm chart with
         clusters:
             - name: targetCluster
     buildSpec:
@@ -33,7 +36,9 @@ spec:
               type: git
         params:
             - name: kubectlArgs
+              description: Extra arguments to pass to kubectl
             - name: pathToFiles
+              description: Path to the manifests to apply
         clusters:
             - name: targetCluster
     buildSpec:

examples/test_tasks.yaml

@@ -10,6 +10,7 @@ spec:
             type: git
         params:
           - name: makeTarget
+            description: The target to have make run
     outputs:
         results:
             - name: testResults
@@ -34,7 +35,9 @@ spec:
              type: git
         params:
             - name: testImage
+              description: The image to use while running the test
             - name: testArgs
+              description: The arguments to pass to the image
     outputs:
         results:
             - name: testResults

pkg/apis/pipeline/v1alpha1/task_types.go

@@ -81,6 +81,9 @@ type Inputs struct {
 // such as resources.
 type TaskParam struct {
 	Name string `json:"name"`
+	Description string `json:"description"`
+	// +optional
+	Default string `json:"default,omitempty"`
 }
 
 // Param declares a value to use for the Param called Name.

pkg/apis/pipeline/v1alpha1/task_validation.go

@@ -61,6 +61,11 @@ func (ts *TaskSpec) Validate() *apis.FieldError {
 		if err := checkForDuplicates(ts.Inputs.Resources, "taskspec.Inputs.Resources.Name"); err != nil {
 			return err
 		}
+		for _, p := range ts.Inputs.Params {
+			if p.Description == "" {
+				return apis.ErrMissingField("taskspec.Inputs.Params.Description")
+			}
+		}
 	}
 	if ts.Outputs != nil {
 		if err := ts.Outputs.Validate("taskspec.Outputs"); err != nil {

pkg/apis/pipeline/v1alpha1/task_validation_test.go

@@ -53,6 +53,12 @@ func TestTaskSpec_Validate(t *testing.T) {
 			fields: fields{
 				Inputs: &Inputs{
 					Resources: []TaskResource{validResource},
+					Params: []TaskParam{
+						{
+							Name: "task",
+							Description: "param",
+						},
+					},
 				},
 				BuildSpec: validBuild,
 			},
@@ -134,6 +140,20 @@ func TestTaskSpec_ValidateError(t *testing.T) {
 				BuildSpec: validBuild,
 			},
 		},
+		{
+			name: "one invalid input param",
+			fields: fields{
+				Inputs: &Inputs{
+					Resources: []TaskResource{validResource},
+					Params: []TaskParam{
+						{
+							Name: "task",
+						},
+					},
+				},
+				BuildSpec: validBuild,
+			},
+		},
 		{
 			name: "one invalid output",
 			fields: fields{

pkg/apis/pipeline/v1alpha1/taskrun_types.go

@@ -94,15 +94,15 @@ type TaskRunStatus struct {
 func (tr *TaskRunStatus) GetCondition(t duckv1alpha1.ConditionType) *duckv1alpha1.Condition {
 	return taskRunCondSet.Manage(tr).GetCondition(t)
 }
-func (ts *TaskRunStatus) InitializeConditions() {
-	taskRunCondSet.Manage(ts).InitializeConditions()
+func (tr *TaskRunStatus) InitializeConditions() {
+	taskRunCondSet.Manage(tr).InitializeConditions()
 }
 
 // SetCondition sets the condition, unsetting previous conditions with the same
 // type as necessary.
-func (ts *TaskRunStatus) SetCondition(newCond *duckv1alpha1.Condition) {
+func (tr *TaskRunStatus) SetCondition(newCond *duckv1alpha1.Condition) {
 	if newCond != nil {
-		taskRunCondSet.Manage(ts).SetCondition(*newCond)
+		taskRunCondSet.Manage(tr).SetCondition(*newCond)
 	}
 }
 
@@ -141,7 +141,7 @@ type TaskRunList struct {
 	Items           []TaskRun `json:"items"`
 }
 
-func (t *TaskRun) SetDefaults() {}
+func (tr *TaskRun) SetDefaults() {}
 
 // GetBuildRef for task
 func (tr *TaskRun) GetBuildRef() corev1.ObjectReference {

pkg/apis/pipeline/v1alpha1/taskrun_validation.go

@@ -24,11 +24,11 @@ import (
 	"k8s.io/apimachinery/pkg/api/equality"
 )
 
-func (t *TaskRun) Validate() *apis.FieldError {
-	if err := validateObjectMetadata(t.GetObjectMeta()).ViaField("metadata"); err != nil {
+func (tr *TaskRun) Validate() *apis.FieldError {
+	if err := validateObjectMetadata(tr.GetObjectMeta()).ViaField("metadata"); err != nil {
 		return err
 	}
-	return t.Spec.Validate()
+	return tr.Spec.Validate()
 }
 
 func (ts *TaskRunSpec) Validate() *apis.FieldError {

pkg/reconciler/v1alpha1/pipelinerun/pipelinerun_test.go

@@ -81,8 +81,10 @@ func TestReconcile(t *testing.T) {
 			Inputs: &v1alpha1.Inputs{
 				Params: []v1alpha1.TaskParam{{
 					Name: "foo",
+					Description: "foo",
 				}, {
 					Name: "bar",
+					Description: "bar",
 				}},
 			},
 		},

pkg/reconciler/v1alpha1/pipelinerun/validate_test.go

@@ -151,8 +151,10 @@ func Test_InvalidPipelineTask(t *testing.T) {
 			Inputs: &v1alpha1.Inputs{
 				Params: []v1alpha1.TaskParam{{
 					Name: "foo",
+					Description: "foo",
 				}, {
 					Name: "bar",
+					Description: "bar",
 				}},
 			},
 		},

pkg/reconciler/v1alpha1/taskrun/resources/apply.go

@@ -25,9 +25,16 @@ import (
 )
 
 // ApplyParameters applies the params from a TaskRun.Input.Parameters to a BuildSpec.
-func ApplyParameters(b *buildv1alpha1.Build, tr *v1alpha1.TaskRun) *buildv1alpha1.Build {
+func ApplyParameters(b *buildv1alpha1.Build, tr *v1alpha1.TaskRun, defaults ...v1alpha1.TaskParam) *buildv1alpha1.Build {
 	// This assumes that the TaskRun inputs have been validated against what the Task requests.
 	replacements := map[string]string{}
+	// Set all the default replacements
+	for _, p := range defaults {
+		if p.Default != "" {
+			replacements[fmt.Sprintf("inputs.params.%s", p.Name)] = p.Default
+		}
+	}
+	// Set and overwrite params with the ones from the TaskRun
 	for _, p := range tr.Spec.Inputs.Params {
 		replacements[fmt.Sprintf("inputs.params.%s", p.Name)] = p.Value
 	}

pkg/reconciler/v1alpha1/taskrun/resources/apply_test.go

@@ -95,6 +95,7 @@ func TestApplyParameters(t *testing.T) {
 	type args struct {
 		b  *buildv1alpha1.Build
 		tr *v1alpha1.TaskRun
+		dp []v1alpha1.TaskParam
 	}
 	tests := []struct {
 		name string
@@ -111,10 +112,27 @@ func TestApplyParameters(t *testing.T) {
 				b.Spec.Steps[0].Image = "bar"
 			}),
 		},
+		{
+			name: "with default parameter",
+			args: args{
+				b:  simpleBuild,
+				tr: &v1alpha1.TaskRun{},
+				dp: []v1alpha1.TaskParam{
+					{
+						Name: "myimage",
+						Default: "mydefault",
+					},
+				},
+
+			},
+			want: applyMutation(simpleBuild, func(b *buildv1alpha1.Build) {
+				b.Spec.Steps[0].Image = "mydefault"
+			}),
+		},
 	}
 	for _, tt := range tests {
 		t.Run(tt.name, func(t *testing.T) {
-			got := ApplyParameters(tt.args.b, tt.args.tr)
+			got := ApplyParameters(tt.args.b, tt.args.tr, tt.args.dp...)
 			if d := cmp.Diff(got, tt.want); d != "" {
 				t.Errorf("ApplyParameters() got diff %s", d)
 			}

pkg/reconciler/v1alpha1/taskrun/resources/input_resources.go

@@ -17,7 +17,7 @@ limitations under the License.
 package resources
 
 import (
-	v1alpha1 "github.com/knative/build-pipeline/pkg/apis/pipeline/v1alpha1"
+	"github.com/knative/build-pipeline/pkg/apis/pipeline/v1alpha1"
 	listers "github.com/knative/build-pipeline/pkg/client/listers/pipeline/v1alpha1"
 	buildv1alpha1 "github.com/knative/build/pkg/apis/build/v1alpha1"
 	"go.uber.org/zap"
@@ -60,6 +60,9 @@ func AddInputResource(
 			break
 		}
 	}
+	if gitResource == nil {
+		return build, nil
+	}
 
 	gitSourceSpec := &buildv1alpha1.GitSourceSpec{
 		Url:      gitResource.URL,

pkg/reconciler/v1alpha1/taskrun/taskrun.go

@@ -328,8 +328,12 @@ func (c *Reconciler) createBuild(tr *v1alpha1.TaskRun, pvcName string) (*buildv1
 		return nil, err
 	}
 
+	var defaults []v1alpha1.TaskParam
+	if t.Spec.Inputs != nil {
+		defaults = append(defaults, t.Spec.Inputs.Params...)
+	}
 	// Apply parameters from the taskrun.
-	build = resources.ApplyParameters(build, tr)
+	build = resources.ApplyParameters(build, tr, defaults...)
 
 	// Apply resources from the taskrun.
 	build, err = resources.ApplyResources(build, tr, c.resourceLister.PipelineResources(t.Namespace))