From 913dd6ccfd5d2a69d4a720933aed6a7b522b6c5d Mon Sep 17 00:00:00 2001
From: Vaughn Dice <vadice@microsoft.com>
Date: Fri, 26 Jul 2019 09:35:09 -0600
Subject: [PATCH] feat(bundle.go): add RequiredExtensions

---
 bundle/bundle.go          | 33 ++++++++++++++++++++-------------
 bundle/bundle_test.go     | 31 ++++++++++++++++++++++++++++++-
 testdata/bundles/foo.json |  5 ++++-
 3 files changed, 54 insertions(+), 15 deletions(-)

diff --git a/bundle/bundle.go b/bundle/bundle.go
index fd7a2595..4edae7b0 100644
--- a/bundle/bundle.go
+++ b/bundle/bundle.go
@@ -16,19 +16,20 @@ import (
 
 // Bundle is a CNAB metadata document
 type Bundle struct {
-	SchemaVersion    string                 `json:"schemaVersion" mapstructure:"schemaVersion"`
-	Name             string                 `json:"name" mapstructure:"name"`
-	Version          string                 `json:"version" mapstructure:"version"`
-	Description      string                 `json:"description" mapstructure:"description"`
-	Keywords         []string               `json:"keywords,omitempty" mapstructure:"keywords"`
-	Maintainers      []Maintainer           `json:"maintainers,omitempty" mapstructure:"maintainers"`
-	InvocationImages []InvocationImage      `json:"invocationImages" mapstructure:"invocationImages"`
-	Images           map[string]Image       `json:"images,omitempty" mapstructure:"images"`
-	Actions          map[string]Action      `json:"actions,omitempty" mapstructure:"actions"`
-	Parameters       *ParametersDefinition  `json:"parameters,omitempty" mapstructure:"parameters"`
-	Credentials      map[string]Credential  `json:"credentials,omitempty" mapstructure:"credentials"`
-	Outputs          *OutputsDefinition     `json:"outputs,omitempty" mapstructure:"outputs"`
-	Definitions      definition.Definitions `json:"definitions,omitempty" mapstructure:"definitions"`
+	SchemaVersion      string                 `json:"schemaVersion" mapstructure:"schemaVersion"`
+	Name               string                 `json:"name" mapstructure:"name"`
+	Version            string                 `json:"version" mapstructure:"version"`
+	Description        string                 `json:"description" mapstructure:"description"`
+	Keywords           []string               `json:"keywords,omitempty" mapstructure:"keywords"`
+	Maintainers        []Maintainer           `json:"maintainers,omitempty" mapstructure:"maintainers"`
+	InvocationImages   []InvocationImage      `json:"invocationImages" mapstructure:"invocationImages"`
+	Images             map[string]Image       `json:"images,omitempty" mapstructure:"images"`
+	Actions            map[string]Action      `json:"actions,omitempty" mapstructure:"actions"`
+	Parameters         *ParametersDefinition  `json:"parameters,omitempty" mapstructure:"parameters"`
+	Credentials        map[string]Credential  `json:"credentials,omitempty" mapstructure:"credentials"`
+	Outputs            *OutputsDefinition     `json:"outputs,omitempty" mapstructure:"outputs"`
+	Definitions        definition.Definitions `json:"definitions,omitempty" mapstructure:"definitions"`
+	RequiredExtensions []string               `json:"requiredExtensions,omitempty" mapstructure:"requiredExtensions"`
 
 	// Custom extension metadata is a named collection of auxiliary data whose
 	// meaning is defined outside of the CNAB specification.
@@ -191,6 +192,12 @@ func (b Bundle) Validate() error {
 		return errors.New("'latest' is not a valid bundle version")
 	}
 
+	for _, requiredExtension := range b.RequiredExtensions {
+		if _, exists := b.Custom[requiredExtension]; !exists {
+			return fmt.Errorf("required extension '%s' is not defined in the Custom section of the bundle", requiredExtension)
+		}
+	}
+
 	for _, img := range b.InvocationImages {
 		err := img.Validate()
 		if err != nil {
diff --git a/bundle/bundle_test.go b/bundle/bundle_test.go
index 2702cc0f..bce7adc8 100644
--- a/bundle/bundle_test.go
+++ b/bundle/bundle_test.go
@@ -339,7 +339,31 @@ func TestValidateBundle_RequiresInvocationImage(t *testing.T) {
 	}
 }
 
-func TestReadCustomExtensions(t *testing.T) {
+func TestValidateRequiredExtensions(t *testing.T) {
+	is := assert.New(t)
+
+	img := InvocationImage{BaseImage{}}
+	b := Bundle{
+		Version:          "0.1.0",
+		SchemaVersion:    "99.98",
+		InvocationImages: []InvocationImage{img},
+		RequiredExtensions: []string{
+			"my.custom.extension",
+		},
+	}
+
+	err := b.Validate()
+	is.EqualError(err, "required extension 'my.custom.extension' is not defined in the Custom section of the bundle")
+
+	b.Custom = map[string]interface{}{
+		"my.custom.extension": true,
+	}
+
+	err = b.Validate()
+	is.NoError(err)
+}
+
+func TestReadCustomAndRequiredExtensions(t *testing.T) {
 	data, err := ioutil.ReadFile("../testdata/bundles/foo.json")
 	if err != nil {
 		t.Errorf("cannot read bundle file: %v", err)
@@ -375,6 +399,11 @@ func TestReadCustomExtensions(t *testing.T) {
 	}
 	assert.Equal(t, true, backupExt["enabled"])
 	assert.Equal(t, "daily", backupExt["frequency"])
+
+	if len(bundle.RequiredExtensions) != 1 {
+		t.Errorf("Expected 1 required extension, got %d", len(bundle.RequiredExtensions))
+	}
+	assert.Equal(t, "com.example.duffle-bag", bundle.RequiredExtensions[0])
 }
 
 func TestOutputs_Marshall(t *testing.T) {
diff --git a/testdata/bundles/foo.json b/testdata/bundles/foo.json
index 8bc23029..2ee51257 100644
--- a/testdata/bundles/foo.json
+++ b/testdata/bundles/foo.json
@@ -77,5 +77,8 @@
                 "path": "/cnab/is/go"
             }
         }
-    }
+    },
+    "requiredExtensions": [
+      "com.example.duffle-bag"
+    ]
 }