Define consts for various Node sources

Co-authored-by: Don Nguyen <dnguyen@pivotal.io>

Author: dfreilich

cmd/detect/main.go

@@ -5,6 +5,8 @@ import (
 	"os"
 	"path/filepath"
 
+	"github.com/cloudfoundry/libcfbuildpack/buildpackplan"
+
 	"github.com/cloudfoundry/libcfbuildpack/helper"
 	"github.com/cloudfoundry/node-engine-cnb/node"
 	"github.com/cloudfoundry/node-engine-cnb/nvmrc"
@@ -37,7 +39,7 @@ func runDetect(context detect.Detect) (int, error) {
 	}
 
 	if nvmrcExists {
-		versionSource = ".nvmrc"
+		versionSource = node.NvmrcSource
 		version, err = nvmrc.GetVersion(nvmrcPath, context.Logger)
 		if err != nil {
 			return context.Fail(), err
@@ -52,7 +54,7 @@ func runDetect(context detect.Detect) (int, error) {
 	}
 
 	if buildpackYamlExists {
-		versionSource = "buildpack.yml"
+		versionSource = node.BuildpackYAMLSource
 		bpYml := &node.BuildpackYAML{}
 		err := helper.ReadBuildpackYaml(buildpackYamlPath, bpYml)
 		if err != nil {
@@ -70,7 +72,7 @@ func runDetect(context detect.Detect) (int, error) {
 			Requires: []buildplan.Required{{
 				Name:     node.Dependency,
 				Version:  version,
-				Metadata: buildplan.Metadata{"launch": true, node.VersionSource: versionSource},
+				Metadata: buildplan.Metadata{"launch": true, buildpackplan.VersionSource: versionSource},
 			}},
 		})
 	}

cmd/detect/main_test.go

@@ -5,6 +5,8 @@ import (
 	"path/filepath"
 	"testing"
 
+	"github.com/cloudfoundry/libcfbuildpack/buildpackplan"
+
 	"github.com/cloudfoundry/node-engine-cnb/node"
 
 	"github.com/buildpack/libbuildpack/buildplan"
@@ -43,7 +45,7 @@ func testDetect(t *testing.T, when spec.G, it spec.S) {
 		})
 
 		it("should request the node version in the buildpack.yml", func() {
-			buildPlan = getStandardBuildplanWithNodeVersion(buildpackYamlVersion, "buildpack.yml")
+			buildPlan = getStandardBuildplanWithNodeVersion(buildpackYamlVersion, node.BuildpackYAMLSource)
 			runDetectAndExpectBuildplan(factory, buildPlan, t)
 		})
 	})
@@ -54,7 +56,7 @@ func testDetect(t *testing.T, when spec.G, it spec.S) {
 		})
 
 		it("should request the node version in the .nvmrc file", func() {
-			buildPlan = getStandardBuildplanWithNodeVersion(nvmrcVersion, ".nvmrc")
+			buildPlan = getStandardBuildplanWithNodeVersion(nvmrcVersion, node.NvmrcSource)
 			runDetectAndExpectBuildplan(factory, buildPlan, t)
 		})
 	})
@@ -66,7 +68,7 @@ func testDetect(t *testing.T, when spec.G, it spec.S) {
 		})
 
 		it("should request the node version in the buildpack.yml", func() {
-			buildPlan = getStandardBuildplanWithNodeVersion(buildpackYamlVersion, "buildpack.yml")
+			buildPlan = getStandardBuildplanWithNodeVersion(buildpackYamlVersion, node.BuildpackYAMLSource)
 			runDetectAndExpectBuildplan(factory, buildPlan, t)
 		})
 	})
@@ -78,7 +80,7 @@ func testDetect(t *testing.T, when spec.G, it spec.S) {
 		})
 
 		it("should request the node version in the .nvmrc", func() {
-			buildPlan = getStandardBuildplanWithNodeVersion(nvmrcVersion, "buildpack.yml")
+			buildPlan = getStandardBuildplanWithNodeVersion(nvmrcVersion, node.BuildpackYAMLSource)
 			runDetectAndExpectBuildplan(factory, buildPlan, t)
 		})
 	})
@@ -102,8 +104,8 @@ func getStandardBuildplanWithNodeVersion(version, versionSource string) buildpla
 			Name:    node.Dependency,
 			Version: version,
 			Metadata: buildplan.Metadata{
-				"launch":           true,
-				node.VersionSource: versionSource,
+				"launch":                    true,
+				buildpackplan.VersionSource: versionSource,
 			}}},
 	}
 }

node/node.go

@@ -10,7 +10,9 @@ import (
 )
 
 const Dependency = "node"
-const VersionSource = "version-source"
+const BuildpackYAMLSource = "buildpack.yml"
+const PackageJsonSource = "package.json"
+const NvmrcSource = ".nvmrc"
 
 type Config struct {
 	OptimizeMemory bool   `yaml:"optimize-memory"`
@@ -29,10 +31,10 @@ type Contributor struct {
 }
 
 var priorities = map[interface{}]int{
-	"buildpack.yml": 3,
-	"package.json":  2,
-	".nvmrc":        1,
-	"":              -1,
+	BuildpackYAMLSource: 3,
+	PackageJsonSource:   2,
+	NvmrcSource:         1,
+	"":                  -1,
 }
 
 func NewContributor(context build.Build) (Contributor, bool, error) {