PPP-3372 Add evaluate variables stage (#90)

* Add types for evaluate variables stage

* Test building evaluate variables stage

* Build evaluate variables stage

* More eval variables tests

* Refactor eval variables to match spec

* Remove redundant test

* Update eval variables yaml field name

* Add doc for evaluate variables stage

README.md

@@ -307,6 +307,26 @@ parameters:
 
 This configures your pipeline to have parameters in the UI / enable pipeline expressions.
 
+### <a name="evaluatevariables"></a> Evaluate Variables Stage
+
+The evaluate variables stage allows you to evaluate complex expressions and use them throughout your pipeline:
+
+```yaml
+- name: "evaluate variables"
+  variables:
+    - key: "my-fun-key"
+      value: ${my-complex-expression}
+```
+
+You can reference the variable by the key name:
+
+```yaml
+- name: "Some other stage"
+  someField: ${ my-fun-key }
+```
+
+### <a name="configurator"></a> Configurator
+
 Files under the `configuratorFiles` section are expected to be in the [k8s-configurator format](https://github.com/namely/k8s-configurator/blob/master/README.md#input-file-and-envs). These will be run through k8s-configurator to generate the environment-specific manifest. By default, the environment used by k8s-configurator will be determined by the account used in this stage. However, you may set the optional `env` property for configuratorFiles to override this.
 
 ```yaml

pipeline/builder/builder.go

@@ -219,6 +219,14 @@ func (b *Builder) Pipeline() (*types.SpinnakerPipeline, error) {
 			stageIndex = stageIndex + 1
 		}
 
+		if stage.EvaluateVariables != nil {
+			s, err = b.buildEvaluateVariablesStage(stageIndex, stage)
+			if err != nil {
+				return sp, fmt.Errorf("failed to build evaluate variables stage with error: %v", err)
+			}
+			stageIndex++
+		}
+
 		if stage.RunSpinnakerPipeline != nil {
 			s, err = b.buildRunSpinnakerPipelineStage(stageIndex, stage)
 			if err != nil {
@@ -621,6 +629,20 @@ func (b *Builder) buildJenkinsStage(index int, s config.Stage) (*types.JenkinsSt
 	return stage, nil
 }
 
+func (b *Builder) buildEvaluateVariablesStage(index int, s config.Stage) (*types.EvaluateVariablesStage, error) {
+	stage := &types.EvaluateVariablesStage{
+		StageMetadata:           buildStageMetadata(s, "evaluatevariables", index, b.isLinear),
+		FailOnFailedExpressions: true,
+		Variables:               make(map[string]string),
+	}
+
+	for _, p := range s.EvaluateVariables.Variables {
+		stage.Variables[p.Key] = p.Value
+	}
+
+	return stage, nil
+}
+
 func (b *Builder) buildRunSpinnakerPipelineStage(index int, s config.Stage) (*types.RunSpinnakerPipelineStage, error) {
 
 	// Set default values

pipeline/builder/builder_test.go

@@ -11,8 +11,8 @@ import (
 	"github.com/stretchr/testify/assert"
 	"github.com/stretchr/testify/require"
 	appsv1 "k8s.io/api/apps/v1"
-	batchv1beta1 "k8s.io/api/batch/v1beta1"
 	batchv1 "k8s.io/api/batch/v1"
+	batchv1beta1 "k8s.io/api/batch/v1beta1"
 	"k8s.io/apimachinery/pkg/runtime"
 )
 
@@ -471,7 +471,7 @@ func TestBuilderPipelineStages(t *testing.T) {
 							{
 								Name: "hello",
 								Resources: &config.Resources{
-									Limits: &config.Resource{Memory: "300Mi", CPU: "300m"},
+									Limits:   &config.Resource{Memory: "300Mi", CPU: "300m"},
 									Requests: &config.Resource{Memory: "500Mi", CPU: "500m"},
 								},
 							},
@@ -508,7 +508,7 @@ func TestBuilderPipelineStages(t *testing.T) {
 							{
 								Name: "pi",
 								Resources: &config.Resources{
-									Limits: &config.Resource{Memory: "300Mi", CPU: "300m"},
+									Limits:   &config.Resource{Memory: "300Mi", CPU: "300m"},
 									Requests: &config.Resource{Memory: "500Mi", CPU: "500m"},
 								},
 							},
@@ -1190,6 +1190,41 @@ func TestBuilderPipelineStages(t *testing.T) {
 		})
 	})
 
+	t.Run("EvaluateVariables stage is parsed correctly", func(t *testing.T) {
+		t.Run("Properties are assigned", func(t *testing.T) {
+			pipeline := &config.Pipeline{
+				Stages: []config.Stage{
+					{
+						Name: "Test EvaluateVariables Stage",
+						EvaluateVariables: &config.EvaluateVariablesStage{
+							Variables: []config.PassthroughParameter{
+								{
+									Key:   "myfunkey",
+									Value: "${mycomplexexpression}",
+								},
+							},
+						},
+					},
+				},
+			}
+
+			builder := builder.New(pipeline)
+			spinnaker, err := builder.Pipeline()
+			require.NoError(t, err, "error generating EvaluateVariables pipeline json")
+
+			stg := spinnaker.Stages[0].(*types.EvaluateVariablesStage)
+			assert.Equal(t, "Test EvaluateVariables Stage", stg.Name)
+			assert.Equal(t, "evaluatevariables", stg.Type)
+
+			variables := stg.Variables
+			assert.Equal(t, "${mycomplexexpression}", variables["myfunkey"])
+
+			assert.True(t, stg.FailOnFailedExpressions)
+
+			t.Logf("%+v\n", stg)
+		})
+	})
+
 	t.Run("RunSpinnakerPipeline stage is parsed correctly", func(t *testing.T) {
 		t.Run("Properties are assigned", func(t *testing.T) {
 

pipeline/builder/types/types.go

@@ -556,3 +556,16 @@ type OptionalStageSupport struct {
 	Expression string `json:"expression"`
 	Type       string `json:"type"`
 }
+
+// EvaluateVariablesStage parses complex expressions for reuse throughout a pipeline
+type EvaluateVariablesStage struct {
+	StageMetadata
+
+	FailOnFailedExpressions bool `json:"failOnFailedExpessions"`
+
+	Variables map[string]string `json:"variables,omitempty"`
+}
+
+func (evs EvaluateVariablesStage) spinnakerStage() {}
+
+var _ Stage = EvaluateVariablesStage{}

pipeline/config/config.go

@@ -160,6 +160,7 @@ type Stage struct {
 	WebHook                 *WebHookStage              `yaml:"webHook,omitempty"`
 	Jenkins                 *JenkinsStage              `yaml:"jenkins,omitempty"`
 	RunSpinnakerPipeline    *RunSpinnakerPipelineStage `yaml:"spinnaker,omitempty"`
+	EvaluateVariables       *EvaluateVariablesStage    `yaml:"variables,omitempty"`
 }
 
 // Notification config from pipeline configuration on a stage or pipeline
@@ -366,3 +367,8 @@ func findImageDescription(containerName string, refs []ImageDescriptionRef) *Ima
 
 	return nil
 }
+
+// EvaluateVariablesStage parses complex expressions for reuse throughout a pipeline
+type EvaluateVariablesStage struct {
+	Variables []PassthroughParameter `yaml:"variables,omitempty"`
+}