Merge pull request #40 from paketo-buildpacks/api/0.5

Buildpack API 0.5

build_test.go

@@ -105,7 +105,10 @@ func testBuild(t *testing.T, context spec.G, it spec.S) {
 	})
 
 	it("handles error from Builder", func() {
-		Expect(ioutil.WriteFile(filepath.Join(buildpackPath, "buildpack.toml"), []byte(`[buildpack]
+		Expect(ioutil.WriteFile(filepath.Join(buildpackPath, "buildpack.toml"), []byte(`
+api = "0.5"
+
+[buildpack]
 name    = "test-name"
 version = "test-version"`),
 			0644)).To(Succeed())

buildpack.go

@@ -83,9 +83,9 @@ type BuildpackDependency struct {
 	Licenses []BuildpackDependencyLicense `toml:"licenses"`
 }
 
-// AsBuildpackPlanEntry renders the dependency as a BuildpackPlanEntry.
-func (b BuildpackDependency) AsBuildpackPlanEntry() libcnb.BuildpackPlanEntry {
-	return libcnb.BuildpackPlanEntry{
+// AsBOMEntry renders a bill of materials entry describing the dependency.
+func (b BuildpackDependency) AsBOMEntry() libcnb.BOMEntry {
+	return libcnb.BOMEntry{
 		Name: b.ID,
 		Metadata: map[string]interface{}{
 			"name":     b.Name,

buildpack_test.go

@@ -33,7 +33,7 @@ func testBuildpack(t *testing.T, context spec.G, it spec.S) {
 		Expect = NewWithT(t).Expect
 	)
 
-	it("renders dependency as an BuildpackPlanEntry", func() {
+	it("renders dependency as a BOMEntry", func() {
 		dependency := libpak.BuildpackDependency{
 			ID:      "test-id",
 			Name:    "test-name",
@@ -49,7 +49,7 @@ func testBuildpack(t *testing.T, context spec.G, it spec.S) {
 			},
 		}
 
-		Expect(dependency.AsBuildpackPlanEntry()).To(Equal(libcnb.BuildpackPlanEntry{
+		Expect(dependency.AsBOMEntry()).To(Equal(libcnb.BOMEntry{
 			Name: dependency.ID,
 			Metadata: map[string]interface{}{
 				"name":     dependency.Name,

detect_test.go

@@ -99,7 +99,10 @@ func testDetect(t *testing.T, context spec.G, it spec.S) {
 	})
 
 	it("handles error from Detector", func() {
-		Expect(ioutil.WriteFile(filepath.Join(buildpackPath, "buildpack.toml"), []byte(`[buildpack]
+		Expect(ioutil.WriteFile(filepath.Join(buildpackPath, "buildpack.toml"), []byte(`
+api = "0.5"
+
+[buildpack]
 name    = "test-name"
 version = "test-version"`),
 			0644)).To(Succeed())

go.mod

@@ -4,7 +4,7 @@ go 1.15
 
 require (
 	github.com/Masterminds/semver/v3 v3.1.1
-	github.com/buildpacks/libcnb v1.18.1
+	github.com/buildpacks/libcnb v1.19.0
 	github.com/creack/pty v1.1.11
 	github.com/heroku/color v0.0.6
 	github.com/imdario/mergo v0.3.11

go.sum

@@ -4,6 +4,8 @@ github.com/Masterminds/semver/v3 v3.1.1 h1:hLg3sBzpNErnxhQtUy/mmLR2I9foDujNK030I
 github.com/Masterminds/semver/v3 v3.1.1/go.mod h1:VPu/7SZ7ePZ3QOrcuXROw5FAcLl4a0cBrbBpGY/8hQs=
 github.com/buildpacks/libcnb v1.18.1 h1:NcAqtyLmSkpcgIOl83GOHY5Mk2ltBFiAI8mmAvavvEs=
 github.com/buildpacks/libcnb v1.18.1/go.mod h1:ozKZYold67tlck+1cobg11YhGmJqkQr8bMAH5gSvEvw=
+github.com/buildpacks/libcnb v1.19.0 h1:7Frn3qErlVmQydk95YXmHtpmf5bZ1l7h4rK/C+SKAmY=
+github.com/buildpacks/libcnb v1.19.0/go.mod h1:slnOsywO4mNdkShkwX1GYR+kQF1tH2F9Urfr66lWGQs=
 github.com/creack/pty v1.1.11 h1:07n33Z8lZxZ2qwegKbObQohDhXDQxiMMz1NOUGYlesw=
 github.com/creack/pty v1.1.11/go.mod h1:oKZEueFk5CKHvIhNR5MUki03XCEU+Q6VDXinZuGJ33E=
 github.com/davecgh/go-spew v1.1.0/go.mod h1:J7Y8YcW2NihsgmVo/mv3lAwl/skON4iLHjSsI+c5H38=

internal/toml_writer.go

@@ -67,7 +67,7 @@ func (t TOMLWriter) Write(path string, value interface{}) error {
 	}
 
 	switch v := value.(type) {
-	case libcnb.Launch:
+	case libcnb.LaunchTOML:
 		if len(v.Slices) > 0 {
 			t.logger.Headerf("%d application slices", len(v.Slices))
 		}

internal/toml_writer_test.go

@@ -87,7 +87,7 @@ other-field = "other-value"`))
 		})
 
 		it("logs []libcnb.Slice", func() {
-			err := tomlWriter.Write(path, libcnb.Launch{
+			err := tomlWriter.Write(path, libcnb.LaunchTOML{
 				Slices: []libcnb.Slice{
 					{},
 					{},
@@ -100,7 +100,7 @@ other-field = "other-value"`))
 		})
 
 		it("logs []libcnb.Label", func() {
-			err := tomlWriter.Write(path, libcnb.Launch{
+			err := tomlWriter.Write(path, libcnb.LaunchTOML{
 				Labels: []libcnb.Label{
 					{Key: "test-key-1"},
 					{Key: "test-key-2"},
@@ -117,7 +117,7 @@ other-field = "other-value"`))
 		context("[]libcnb.Process", func() {
 
 			it("aligns process types", func() {
-				err := tomlWriter.Write(path, libcnb.Launch{
+				err := tomlWriter.Write(path, libcnb.LaunchTOML{
 					Processes: []libcnb.Process{
 						{Type: "short", Command: "test-command-1"},
 						{Type: "a-very-long-type", Command: "test-command-2"},
@@ -133,7 +133,7 @@ other-field = "other-value"`))
 			})
 
 			it("appends arguments", func() {
-				err := tomlWriter.Write(path, libcnb.Launch{
+				err := tomlWriter.Write(path, libcnb.LaunchTOML{
 					Processes: []libcnb.Process{
 						{Type: "test-type", Command: "test-command", Arguments: []string{"test-arg-1", "test-arg-2"}},
 					},
@@ -147,7 +147,7 @@ other-field = "other-value"`))
 			})
 
 			it("indicates direct", func() {
-				err := tomlWriter.Write(path, libcnb.Launch{
+				err := tomlWriter.Write(path, libcnb.LaunchTOML{
 					Processes: []libcnb.Process{
 						{Type: "test-type", Command: "test-command", Direct: true},
 					},

layer.go

@@ -21,7 +21,6 @@ import (
 	"os"
 	"path/filepath"
 	"reflect"
-	"strings"
 
 	"github.com/heroku/color"
 	"github.com/pelletier/go-toml"
@@ -45,29 +44,26 @@ type LayerContributor struct {
 
 	// Name is the user readable name of the contribution.
 	Name string
+
+	// ExpectedTypes indicates the types that should be set on the layer.
+	ExpectedTypes libcnb.LayerTypes
 }
 
 // NewLayerContributor creates a new instance.
-func NewLayerContributor(name string, expectedMetadata interface{}) LayerContributor {
+func NewLayerContributor(name string, expectedMetadata interface{}, expectedTypes libcnb.LayerTypes) LayerContributor {
 	return LayerContributor{
 		ExpectedMetadata: expectedMetadata,
 		Name:             name,
+		ExpectedTypes:    expectedTypes,
 	}
 }
 
 // LayerFunc is a callback function that is invoked when a layer needs to be contributed.
 type LayerFunc func() (libcnb.Layer, error)
 
-type LayerFlag uint8
-
-const (
-	BuildLayer LayerFlag = iota
-	CacheLayer
-	LaunchLayer
-)
 
 // Contribute is the function to call when implementing your libcnb.LayerContributor.
-func (l *LayerContributor) Contribute(layer libcnb.Layer, f LayerFunc, flags ...LayerFlag) (libcnb.Layer, error) {
+func (l *LayerContributor) Contribute(layer libcnb.Layer, f LayerFunc) (libcnb.Layer, error) {
 	raw, err := toml.Marshal(l.ExpectedMetadata)
 	if err != nil {
 		return libcnb.Layer{}, fmt.Errorf("unable to encode metadata\n%w", err)
@@ -81,6 +77,7 @@ func (l *LayerContributor) Contribute(layer libcnb.Layer, f LayerFunc, flags ...
 	l.Logger.Debugf("Expected metadata: %+v", expected)
 	l.Logger.Debugf("Actual metadata: %+v", layer.Metadata)
 
+	// TODO: compare entire layer not just metadata (in case build, launch, or cache have changed)
 	if reflect.DeepEqual(expected, layer.Metadata) {
 		l.Logger.Headerf("%s: %s cached layer", color.BlueString(l.Name), color.GreenString("Reusing"))
 		return layer, nil
@@ -101,17 +98,7 @@ func (l *LayerContributor) Contribute(layer libcnb.Layer, f LayerFunc, flags ...
 		return libcnb.Layer{}, err
 	}
 
-	for _, f := range flags {
-		switch f {
-		case BuildLayer:
-			layer.Build = true
-		case CacheLayer:
-			layer.Cache = true
-		case LaunchLayer:
-			layer.Launch = true
-		}
-	}
-
+	layer.LayerTypes = l.ExpectedTypes
 	layer.Metadata = expected
 
 	return layer, nil
@@ -127,8 +114,11 @@ type DependencyLayerContributor struct {
 	// DependencyCache is the cache to use to get the dependency.
 	DependencyCache DependencyCache
 
-	// LayerContributor is the contained LayerContributor used for the actual contribution.
-	LayerContributor LayerContributor
+	// ExpectedTypes indicates the types that should be set on the layer.
+	ExpectedTypes libcnb.LayerTypes
+
+	// ExpectedMetadata contains metadata describing the expected layer
+	ExpectedMetadata interface{}
 
 	// Logger is the logger to use.
 	Logger bard.Logger
@@ -137,53 +127,67 @@ type DependencyLayerContributor struct {
 	RequestModifierFuncs []RequestModifierFunc
 }
 
-// NewDependencyLayerContributor creates a new instance and adds the dependency to the Buildpack Plan.
-func NewDependencyLayerContributor(dependency BuildpackDependency, cache DependencyCache, plan *libcnb.BuildpackPlan) DependencyLayerContributor {
+// NewDependencyLayer returns a new DependencyLayerContributor for the given BuildpackDependency and a BOMEntry describing the layer contents.
+func NewDependencyLayer(dependency BuildpackDependency, cache DependencyCache, types libcnb.LayerTypes) (DependencyLayerContributor, libcnb.BOMEntry) {
 	c := DependencyLayerContributor{
 		Dependency:       dependency,
+		ExpectedMetadata: dependency,
 		DependencyCache:  cache,
-		LayerContributor: NewLayerContributor(fmt.Sprintf("%s %s", dependency.Name, dependency.Version), dependency),
+		ExpectedTypes:    types,
 	}
 
-	entry := dependency.AsBuildpackPlanEntry()
+	entry := dependency.AsBOMEntry()
 	entry.Metadata["layer"] = c.LayerName()
-	plan.Entries = append(plan.Entries, entry)
 
-	return c
+	if types.Launch {
+		entry.Launch = true
+	}
+	if !(types.Launch && !types.Cache && !types.Build) {
+		// launch-only layers are the only layers NOT guaranteed to be present in the build environment
+		entry.Build = true
+	}
+
+	return c, entry
 }
 
 // DependencyLayerFunc is a callback function that is invoked when a dependency needs to be contributed.
 type DependencyLayerFunc func(artifact *os.File) (libcnb.Layer, error)
 
 // Contribute is the function to call whe implementing your libcnb.LayerContributor.
-func (d *DependencyLayerContributor) Contribute(layer libcnb.Layer, f DependencyLayerFunc, flags ...LayerFlag) (libcnb.Layer, error) {
-	d.LayerContributor.Logger = d.Logger
+func (d *DependencyLayerContributor) Contribute(layer libcnb.Layer, f DependencyLayerFunc) (libcnb.Layer, error) {
+	lc := NewLayerContributor(d.Name(), d.ExpectedMetadata, d.ExpectedTypes)
+	lc.Logger = d.Logger
 
-	return d.LayerContributor.Contribute(layer, func() (libcnb.Layer, error) {
+	return lc.Contribute(layer, func() (libcnb.Layer, error) {
 		artifact, err := d.DependencyCache.Artifact(d.Dependency, d.RequestModifierFuncs...)
 		if err != nil {
 			return libcnb.Layer{}, fmt.Errorf("unable to get dependency %s\n%w", d.Dependency.ID, err)
 		}
 		defer artifact.Close()
 
 		return f(artifact)
-	}, flags...)
+	})
 }
 
 // LayerName returns the conventional name of the layer for this contributor
 func (d *DependencyLayerContributor) LayerName() string {
 	return d.Dependency.ID
 }
 
+// Name returns the human readable name of the layer
+func (d *DependencyLayerContributor) Name() string {
+	return fmt.Sprintf("%s %s", d.Dependency.Name, d.Dependency.Version)
+}
+
 // HelperLayerContributor is a helper for implementing a libcnb.LayerContributor for a buildpack helper application in
 // order to get consistent logging and avoidance.
 type HelperLayerContributor struct {
 
 	// Path is the path to the helper application.
 	Path string
 
-	// LayerContributor is the contained LayerContributor used for the actual contribution.
-	LayerContributor LayerContributor
+	// BuildpackInfo describes the buildpack that provides the helper
+	BuildpackInfo libcnb.BuildpackInfo
 
 	// Logger is the logger to use.
 	Logger bard.Logger
@@ -192,31 +196,40 @@ type HelperLayerContributor struct {
 	Names []string
 }
 
-// NewHelperLayerContributor creates a new instance and adds the helper to the Buildpack Plan.
-func NewHelperLayerContributor(buildpack libcnb.Buildpack, plan *libcnb.BuildpackPlan, names ...string) HelperLayerContributor {
+// NewHelperLayer returns a new HelperLayerContributor and a BOMEntry describing the layer contents.
+func NewHelperLayer(buildpack libcnb.Buildpack, names ...string) (HelperLayerContributor, libcnb.BOMEntry) {
 	c := HelperLayerContributor{
-		Path:             filepath.Join(buildpack.Path, "bin", "helper"),
-		LayerContributor: NewLayerContributor("Launch Helper", buildpack.Info),
-		Names:            names,
+		Path:          filepath.Join(buildpack.Path, "bin", "helper"),
+		Names:         names,
+		BuildpackInfo: buildpack.Info,
 	}
 
-	plan.Entries = append(plan.Entries, libcnb.BuildpackPlanEntry{
+	entry := libcnb.BOMEntry{
 		Name: "helper",
 		Metadata: map[string]interface{}{
 			"layer":   c.Name(),
 			"names":   names,
 			"version": buildpack.Info.Version,
 		},
-	})
+		Launch: true,
+	}
+
+	return c, entry
+}
 
-	return c
+// Name returns the conventional name of the layer for this contributor
+func (h HelperLayerContributor) Name() string {
+	return filepath.Base(h.Path)
 }
 
 // Contribute is the function to call whe implementing your libcnb.LayerContributor.
 func (h HelperLayerContributor) Contribute(layer libcnb.Layer) (libcnb.Layer, error) {
-	h.LayerContributor.Logger = h.Logger
+	lc := NewLayerContributor("Launch Helper", h.BuildpackInfo, libcnb.LayerTypes{
+		Launch: true,
+	})
+	lc.Logger = h.Logger
 
-	return h.LayerContributor.Contribute(layer, func() (libcnb.Layer, error) {
+	return lc.Contribute(layer, func() (libcnb.Layer, error) {
 		in, err := os.Open(h.Path)
 		if err != nil {
 			return libcnb.Layer{}, fmt.Errorf("unable to open %s\n%w", h.Path, err)
@@ -228,7 +241,6 @@ func (h HelperLayerContributor) Contribute(layer libcnb.Layer) (libcnb.Layer, er
 			return libcnb.Layer{}, fmt.Errorf("unable to copy %s to %s", h.Path, out)
 		}
 
-		var p []string
 		for _, n := range h.Names {
 			link := layer.Exec.FilePath(n)
 			h.Logger.Bodyf("Creating %s", link)
@@ -241,24 +253,8 @@ func (h HelperLayerContributor) Contribute(layer libcnb.Layer) (libcnb.Layer, er
 			if err := os.Symlink(out, link); err != nil {
 				return libcnb.Layer{}, fmt.Errorf("unable to link %s to %s\n%w", out, link, err)
 			}
-
-			p = append(p,
-				"exec 4<&1",
-				fmt.Sprintf(`for_export=$(%s 3>&1 >&4) || exit $?`, link),
-				"exec 4<&-",
-				"set -a",
-				`eval "$for_export"`,
-				"set +a",
-			)
 		}
 
-		layer.Profile.Add("helper", strings.Join(p, "\n"))
-
 		return layer, nil
-	}, LaunchLayer)
-}
-
-// Name returns the conventional name of the layer for this contributor
-func (h HelperLayerContributor) Name() string {
-	return filepath.Base(h.Path)
+	})
 }