Add Validators and Transformers (#409)

pkg/config/draftconfig.go

@@ -5,6 +5,8 @@ import (
 	"fmt"
 	"io/fs"
 
+	"github.com/Azure/draft/pkg/config/transformers"
+	"github.com/Azure/draft/pkg/config/validators"
 	log "github.com/sirupsen/logrus"
 	"gopkg.in/yaml.v2"
 
@@ -13,34 +15,46 @@ import (
 
 const draftConfigFile = "draft.yaml"
 
+type VariableValidator func(string) error
+type VariableTransformer func(string) (string, error)
+
 type DraftConfig struct {
-	TemplateName        string            `yaml:"templateName"`
-	DisplayName         string            `yaml:"displayName"`
-	Description         string            `yaml:"description"`
-	Type                string            `yaml:"type"`
-	Versions            string            `yaml:"versions"`
-	DefaultVersion      string            `yaml:"defaultVersion"`
-	Variables           []*BuilderVar     `yaml:"variables"`
-	FileNameOverrideMap map[string]string `yaml:"filenameOverrideMap"`
+	TemplateName        string                         `yaml:"templateName"`
+	DisplayName         string                         `yaml:"displayName"`
+	Description         string                         `yaml:"description"`
+	Type                string                         `yaml:"type"`
+	Versions            string                         `yaml:"versions"`
+	DefaultVersion      string                         `yaml:"defaultVersion"`
+	Variables           []*BuilderVar                  `yaml:"variables"`
+	FileNameOverrideMap map[string]string              `yaml:"filenameOverrideMap"`
+	Validators          map[string]VariableValidator   `yaml:"validators"`
+	Transformers        map[string]VariableTransformer `yaml:"transformers"`
 }
 
 type BuilderVar struct {
-	Name          string            `yaml:"name"`
-	Default       BuilderVarDefault `yaml:"default"`
-	Description   string            `yaml:"description"`
-	ExampleValues []string          `yaml:"exampleValues"`
-	Type          string            `yaml:"type"`
-	Kind          string            `yaml:"kind"`
-	Value         string            `yaml:"value"`
-	Versions      string            `yaml:"versions"`
+	Name           string                         `yaml:"name"`
+	ConditionalRef BuilderVarConditionalReference `yaml:"conditionalReference"`
+	Default        BuilderVarDefault              `yaml:"default"`
+	Description    string                         `yaml:"description"`
+	ExampleValues  []string                       `yaml:"exampleValues"`
+	Type           string                         `yaml:"type"`
+	Kind           string                         `yaml:"kind"`
+	Value          string                         `yaml:"value"`
+	Versions       string                         `yaml:"versions"`
 }
 
+// BuilderVarDefault holds info on the default value of a variable
 type BuilderVarDefault struct {
 	IsPromptDisabled bool   `yaml:"disablePrompt"`
 	ReferenceVar     string `yaml:"referenceVar"`
 	Value            string `yaml:"value"`
 }
 
+// BuilderVarConditionalReference holds a reference to a variable thats value can effect validation/transformation of the associated variable
+type BuilderVarConditionalReference struct {
+	ReferenceVar string `yaml:"referenceVar"`
+}
+
 func NewConfigFromFS(fileSys fs.FS, path string) (*DraftConfig, error) {
 	configBytes, err := fs.ReadFile(fileSys, path)
 	if err != nil {
@@ -91,7 +105,17 @@ func (d *DraftConfig) GetVariableValue(name string) (string, error) {
 			if variable.Value == "" {
 				return "", fmt.Errorf("variable %s has no value", name)
 			}
-			return variable.Value, nil
+
+			if err := d.GetVariableValidator(variable.Kind)(variable.Value); err != nil {
+				return "", fmt.Errorf("failed variable validation: %w", err)
+			}
+
+			response, err := d.GetVariableTransformer(variable.Kind)(variable.Value)
+			if err != nil {
+				return "", fmt.Errorf("failed variable transformation: %w", err)
+			}
+
+			return response, nil
 		}
 	}
 
@@ -109,6 +133,44 @@ func (d *DraftConfig) SetVariable(name, value string) {
 	}
 }
 
+// GetVariableTransformer returns the transformer for a specific variable kind
+func (d *DraftConfig) GetVariableTransformer(kind string) VariableTransformer {
+	// user overrides
+	if transformer, ok := d.Transformers[kind]; ok {
+		return transformer
+	}
+
+	// internally defined transformers
+	return transformers.GetTransformer(kind)
+}
+
+// GetVariableValidator returns the validator for a specific variable kind
+func (d *DraftConfig) GetVariableValidator(kind string) VariableValidator {
+	// user overrides
+	if validator, ok := d.Validators[kind]; ok {
+		return validator
+	}
+
+	// internally defined validators
+	return validators.GetValidator(kind)
+}
+
+// SetVariableTransformer sets the transformer for a specific variable kind
+func (d *DraftConfig) SetVariableTransformer(kind string, transformer VariableTransformer) {
+	if d.Transformers == nil {
+		d.Transformers = make(map[string]VariableTransformer)
+	}
+	d.Transformers[kind] = transformer
+}
+
+// SetVariableValidator sets the validator for a specific variable kind
+func (d *DraftConfig) SetVariableValidator(kind string, validator VariableValidator) {
+	if d.Validators == nil {
+		d.Validators = make(map[string]VariableValidator)
+	}
+	d.Validators[kind] = validator
+}
+
 // ApplyDefaultVariables will apply the defaults to variables that are not already set
 func (d *DraftConfig) ApplyDefaultVariables() error {
 	for _, variable := range d.Variables {

pkg/config/draftconfig_template_test.go

@@ -3,13 +3,17 @@ package config
 import (
 	"fmt"
 	"io/fs"
+	"regexp"
 	"strings"
 	"testing"
 
 	"github.com/Azure/draft/template"
+	"github.com/blang/semver/v4"
 	"github.com/stretchr/testify/assert"
 )
 
+const alphaNumUnderscoreHyphen = "^[A-Za-z][A-Za-z0-9-_]{1,62}[A-Za-z0-9]$"
+
 var allTemplates = map[string]*DraftConfig{}
 
 var validTemplateTypes = map[string]bool{
@@ -67,6 +71,7 @@ func TestTempalteValidation(t *testing.T) {
 }
 
 func loadTemplatesWithValidation() error {
+	regexp := regexp.MustCompile(alphaNumUnderscoreHyphen)
 	return fs.WalkDir(template.Templates, ".", func(path string, d fs.DirEntry, err error) error {
 		if err != nil {
 			return err
@@ -93,6 +98,10 @@ func loadTemplatesWithValidation() error {
 			return fmt.Errorf("template %s has no template name", path)
 		}
 
+		if !regexp.MatchString(currTemplate.TemplateName) {
+			return fmt.Errorf("template %s name must match the alpha-numeric-underscore-hyphen regex: %s", path, currTemplate.TemplateName)
+		}
+
 		if _, ok := allTemplates[strings.ToLower(currTemplate.TemplateName)]; ok {
 			return fmt.Errorf("template %s has a duplicate template name", path)
 		}
@@ -101,12 +110,12 @@ func loadTemplatesWithValidation() error {
 			return fmt.Errorf("template %s has an invalid type: %s", path, currTemplate.Type)
 		}
 
-		// version range check once we define versions
-		// if _, err := semver.ParseRange(currTemplate.Versions); err != nil {
-		// 	return fmt.Errorf("template %s has an invalid version range: %s", path, currTemplate.Versions)
-		// }
+		if _, err := semver.ParseRange(currTemplate.Versions); err != nil {
+			return fmt.Errorf("template %s has an invalid version range: %s", path, currTemplate.Versions)
+		}
 
 		referenceVarMap := map[string]*BuilderVar{}
+		conditionRefMap := map[string]*BuilderVar{}
 		allVariables := map[string]*BuilderVar{}
 		for _, variable := range currTemplate.Variables {
 			if variable.Name == "" {
@@ -121,29 +130,43 @@ func loadTemplatesWithValidation() error {
 				return fmt.Errorf("template %s has an invalid variable kind: %s", path, variable.Kind)
 			}
 
-			// version range check once we define versions
-			// if _, err := semver.ParseRange(variable.Versions); err != nil {
-			// 	return fmt.Errorf("template %s has an invalid version range: %s", path, variable.Versions)
-			// }
+			if _, err := semver.ParseRange(variable.Versions); err != nil {
+				return fmt.Errorf("template %s has an invalid version range: %s", path, variable.Versions)
+			}
 
 			allVariables[variable.Name] = variable
 			if variable.Default.ReferenceVar != "" {
 				referenceVarMap[variable.Name] = variable
 			}
+
+			if variable.ConditionalRef.ReferenceVar != "" {
+				conditionRefMap[variable.Name] = variable
+			}
 		}
 
 		for _, currVar := range referenceVarMap {
 			refVar, ok := allVariables[currVar.Default.ReferenceVar]
 			if !ok {
-				return fmt.Errorf("template %s has a variable %s with reference to a non-existent variable: %s", path, currVar.Name, currVar.Default.ReferenceVar)
+				return fmt.Errorf("template %s has a variable %s with default reference to a non-existent variable: %s", path, currVar.Name, currVar.Default.ReferenceVar)
 			}
 
 			if currVar.Name == refVar.Name {
-				return fmt.Errorf("template %s has a variable with cyclical reference to itself: %s", path, currVar.Name)
+				return fmt.Errorf("template %s has a variable with cyclical default reference to itself: %s", path, currVar.Name)
+			}
+
+			if isCyclicalDefaultVariableReference(currVar, refVar, allVariables, map[string]bool{}) {
+				return fmt.Errorf("template %s has a variable with cyclical default reference to itself: %s", path, currVar.Name)
+			}
+		}
+
+		for _, currVar := range conditionRefMap {
+			refVar, ok := allVariables[currVar.ConditionalRef.ReferenceVar]
+			if !ok {
+				return fmt.Errorf("template %s has a variable %s with conditional reference to a non-existent variable: %s", path, currVar.Name, currVar.ConditionalRef.ReferenceVar)
 			}
 
-			if isCyclicalVariableReference(currVar, refVar, allVariables, map[string]bool{}) {
-				return fmt.Errorf("template %s has a variable with cyclical reference to itself: %s", path, currVar.Name)
+			if isCyclicalConditionalVariableReference(currVar, refVar, allVariables, map[string]bool{}) {
+				return fmt.Errorf("template %s has a variable with cyclical conditional reference to itself or references a non existing variable: %s", path, currVar.Name)
 			}
 		}
 
@@ -152,7 +175,7 @@ func loadTemplatesWithValidation() error {
 	})
 }
 
-func isCyclicalVariableReference(initialVar, currRefVar *BuilderVar, allVariables map[string]*BuilderVar, visited map[string]bool) bool {
+func isCyclicalDefaultVariableReference(initialVar, currRefVar *BuilderVar, allVariables map[string]*BuilderVar, visited map[string]bool) bool {
 	if initialVar.Name == currRefVar.Name {
 		return true
 	}
@@ -171,5 +194,27 @@ func isCyclicalVariableReference(initialVar, currRefVar *BuilderVar, allVariable
 	}
 
 	visited[currRefVar.Name] = true
-	return isCyclicalVariableReference(initialVar, refVar, allVariables, visited)
+	return isCyclicalDefaultVariableReference(initialVar, refVar, allVariables, visited)
+}
+
+func isCyclicalConditionalVariableReference(initialVar, currRefVar *BuilderVar, allVariables map[string]*BuilderVar, visited map[string]bool) bool {
+	if initialVar.Name == currRefVar.Name {
+		return true
+	}
+
+	if _, ok := visited[currRefVar.Name]; ok {
+		return true
+	}
+
+	if currRefVar.ConditionalRef.ReferenceVar == "" {
+		return false
+	}
+
+	refVar, ok := allVariables[currRefVar.ConditionalRef.ReferenceVar]
+	if !ok {
+		return false
+	}
+
+	visited[currRefVar.Name] = true
+	return isCyclicalConditionalVariableReference(initialVar, refVar, allVariables, visited)
 }

pkg/config/transformers/transformers.go

@@ -0,0 +1,12 @@
+package transformers
+
+func GetTransformer(variableKind string) func(string) (string, error) {
+	switch variableKind {
+	default:
+		return DefaultTransformer
+	}
+}
+
+func DefaultTransformer(inputVar string) (string, error) {
+	return inputVar, nil
+}

pkg/config/transformers/transformers_test.go

@@ -0,0 +1,17 @@
+package transformers
+
+import (
+	"testing"
+
+	"github.com/stretchr/testify/assert"
+)
+
+func TestGetTransformer(t *testing.T) {
+	assert.NotNil(t, GetTransformer("NonExistentKind"))
+}
+
+func TestDefaultTransformer(t *testing.T) {
+	res, err := DefaultTransformer("test")
+	assert.Nil(t, err)
+	assert.Equal(t, "test", res)
+}

pkg/config/validators/validators.go

@@ -0,0 +1,12 @@
+package validators
+
+func GetValidator(variableKind string) func(string) error {
+	switch variableKind {
+	default:
+		return DefaultValidator
+	}
+}
+
+func DefaultValidator(input string) error {
+	return nil
+}

pkg/config/validators/validators_test.go

@@ -0,0 +1,15 @@
+package validators
+
+import (
+	"testing"
+
+	"github.com/stretchr/testify/assert"
+)
+
+func TestGetValidator(t *testing.T) {
+	assert.NotNil(t, GetValidator("NonExistentKind"))
+}
+
+func TestDefaultValidator(t *testing.T) {
+	assert.Nil(t, DefaultValidator("test"))
+}

pkg/fixtures/manifests/hpa/hpa.yaml

@@ -0,0 +1,22 @@
+apiVersion: autoscaling/v2
+kind: HorizontalPodAutoscaler
+metadata:
+  name: test-app
+  labels:
+    app.kubernetes.io/name: test-app
+    app.kubernetes.io/part-of: test-app-project
+    kubernetes.azure.com/generator: draft
+spec:
+  scaleTargetRef:
+    apiVersion: apps/v1
+    kind: Deployment
+    name: test-app
+  minReplicas: 2
+  maxReplicas: 5
+  metrics:
+    - type: Resource
+      resource:
+        name: cpu
+        target:
+          type: Utilization
+          averageUtilization: 80

pkg/fixtures/manifests/pdb/pdb.yaml

@@ -0,0 +1,13 @@
+apiVersion: policy/v1
+kind: PodDisruptionBudget
+metadata:
+  name: test-app
+  labels:
+    app.kubernetes.io/name: test-app
+    app.kubernetes.io/part-of: test-app-project
+    kubernetes.azure.com/generator: draft
+spec:
+  maxUnavailable: 1
+  selector:
+    matchLabels:
+      app: test-app

pkg/fixtures/manifests/service/service.yaml

@@ -0,0 +1,16 @@
+apiVersion: v1
+kind: Service
+metadata:
+  name: test-app
+  labels:
+    app.kubernetes.io/name: test-app
+    app.kubernetes.io/part-of: test-app-project
+    kubernetes.azure.com/generator: draft
+spec:
+  type: ClusterIP
+  selector:
+    app: test-app
+  ports:
+    - protocol: TCP
+      port: 80
+      targetPort: 80