Add dependencies-v2 experimental flag

This introduces the dependencies-v2 experimental flag, under which any
changes from PEP003 - Advanced Dependencies will be implemented.

I have updated the porter.yaml to bundle.json adapter so that if someone
is using the flag now, they get an error that it's not implemented.

Signed-off-by: Carolyn Van Slyck <[email protected]>

docs/content/configuration.md

@@ -17,6 +17,7 @@ You may set a default value for a configuration value in the config file, overri
 * [Experimental Feature Flags](#experimental-feature-flags)
   * [Build Drivers](#build-drivers)
   * [Structured Logs](#structured-logs)
+  * [Dependencies v2](#dependencies-v2)
 * [Common Configuration Settings](#common-configuration-settings)
   * [Set Current Namespace](#namespace)
   * [Enable Debug Output](#debug)
@@ -259,6 +260,11 @@ Below is a sample Porter configuration file that demonstrates how to set each of
 
 [otel]: https://github.com/open-telemetry/opentelemetry-specification/blob/v1.8.0/specification/protocol/exporter.md
 
+### Dependencies v2
+
+The `dependencies-v2` experimental flag is not yet implemented.
+When it is completed, it is used to activate the features from [PEP003 - Advanced Dependencies](https://github.com/getporter/proposals/blob/main/pep/003-dependency-namespaces-and-labels.md).
+
 ## Common Configuration Settings
 
 Some configuration settings are applicable to many of Porter's commands and to save time you may want to set these values in the configuration file or with environment variables.

go.mod

@@ -54,7 +54,6 @@ require (
 	github.com/osteele/liquid v1.3.0
 	github.com/pelletier/go-toml v1.9.4
 	github.com/pivotal/image-relocation v0.0.0-20191111101224-e94aff6df06c
-	github.com/pkg/errors v0.9.1
 	github.com/spf13/afero v1.5.1
 	github.com/spf13/cobra v1.2.1
 	github.com/spf13/pflag v1.0.5
@@ -174,6 +173,7 @@ require (
 	github.com/opencontainers/runc v1.1.2 // indirect
 	github.com/osteele/tuesday v1.0.3 // indirect
 	github.com/pierrec/lz4/v4 v4.0.3 // indirect
+	github.com/pkg/errors v0.9.1 // indirect
 	github.com/pmezard/go-difflib v1.0.0 // indirect
 	github.com/prometheus/client_golang v1.12.1 // indirect
 	github.com/prometheus/client_model v0.2.0 // indirect

pkg/cnab/config-adapter/adapter.go

@@ -9,6 +9,7 @@ import (
 	"get.porter.sh/porter/pkg/cnab"
 	depsv1 "get.porter.sh/porter/pkg/cnab/dependencies/v1"
 	"get.porter.sh/porter/pkg/config"
+	"get.porter.sh/porter/pkg/experimental"
 	"get.porter.sh/porter/pkg/manifest"
 	"get.porter.sh/porter/pkg/mixin"
 	"get.porter.sh/porter/pkg/tracing"
@@ -407,7 +408,24 @@ func (c *ManifestConverter) generateBundleImages() map[string]bundle.Image {
 	return images
 }
 
-func (c *ManifestConverter) generateDependencies() (*depsv1.Dependencies, error) {
+func (c *ManifestConverter) generateDependencies() (interface{}, string, error) {
+	if len(c.Manifest.Dependencies.RequiredDependencies) == 0 {
+		return nil, "", nil
+	}
+
+	// Check if they are using v1 of the dependencies spec or v2
+	if c.config.IsFeatureEnabled(experimental.FlagDependenciesV2) {
+		panic("the dependencies-v2 experimental flag was specified but is not yet implemented")
+	}
+
+	deps, err := c.generateDependenciesV1()
+	if err != nil {
+		return nil, "", err
+	}
+	return deps, cnab.DependenciesV1ExtensionKey, nil
+}
+
+func (c *ManifestConverter) generateDependenciesV1() (*depsv1.Dependencies, error) {
 	if len(c.Manifest.Dependencies.RequiredDependencies) == 0 {
 		return nil, nil
 	}
@@ -598,12 +616,12 @@ func (c *ManifestConverter) generateCustomExtensions(b *cnab.ExtendedBundle) (ma
 	}
 
 	// Add the dependency extension
-	deps, err := c.generateDependencies()
+	deps, depsExtKey, err := c.generateDependencies()
 	if err != nil {
 		return nil, err
 	}
-	if deps != nil && len(deps.Requires) > 0 {
-		customExtensions[cnab.DependenciesV1ExtensionKey] = deps
+	if depsExtKey != "" {
+		customExtensions[depsExtKey] = deps
 	}
 
 	// Add the parameter sources extension

pkg/cnab/config-adapter/adapter_test.go

@@ -579,8 +579,11 @@ func TestManifestConverter_generateDependencies(t *testing.T) {
 
 			a := NewManifestConverter(c.Config, m, nil, nil)
 
-			deps, err := a.generateDependencies()
-			require.NoError(t, err, "generateDependencies failed")
+			depsExt, depsExtKey, err := a.generateDependencies()
+			require.NoError(t, err)
+			require.Equal(t, cnab.DependenciesV1ExtensionKey, depsExtKey, "expected the v1 dependencies extension key")
+			require.IsType(t, &depsv1.Dependencies{}, depsExt, "expected a v1 dependencies extension section")
+			deps := depsExt.(*depsv1.Dependencies)
 			require.Len(t, deps.Requires, 3, "incorrect number of dependencies were generated")
 			require.Equal(t, []string{"mysql", "ad", "storage"}, deps.Sequence, "incorrect sequence was generated")
 

pkg/experimental/experimental.go

@@ -3,6 +3,9 @@ package experimental
 const (
 	// NoopFeature is a placeholder feature flag that allows us to test our feature flag functions even when there are no active feature flags
 	NoopFeature = "no-op"
+
+	// DependenciesV2 is the name of the experimental feature flag for PEP003 - Advanced Dependencies.
+	DependenciesV2 = "dependencies-v2"
 )
 
 // FeatureFlags is an enum of possible feature flags
@@ -11,6 +14,9 @@ type FeatureFlags int
 const (
 	// FlagNoopFeature is a placeholder feature flag that allows us to test our feature flag functions even when there are no active feature flags
 	FlagNoopFeature FeatureFlags = iota + 1
+
+	// FlagDependenciesV2 gates the changes from PEP003 - Advanced Dependencies.
+	FlagDependenciesV2
 )
 
 // ParseFlags converts a list of feature flag names into a bit map for faster lookups.
@@ -20,6 +26,8 @@ func ParseFlags(flags []string) FeatureFlags {
 		switch flag {
 		case NoopFeature:
 			experimental = experimental | FlagNoopFeature
+		case DependenciesV2:
+			experimental = experimental | FlagDependenciesV2
 		}
 	}
 	return experimental