Recreate layer symlink if it already exists (#386)

cmd/setup-symlinks/internal/run.go

@@ -14,7 +14,12 @@ func Run(executablePath, appDir, tmpDir string) error {
 		layerPath = fmt.Sprintf("/%s", layerPath)
 	}
 
-	err := os.Symlink(filepath.Join(layerPath, "node_modules"), filepath.Join(tmpDir, "node_modules"))
+	err := os.RemoveAll(filepath.Join(tmpDir, "node_modules"))
+	if err != nil {
+		return err
+	}
+
+	err = os.Symlink(filepath.Join(layerPath, "node_modules"), filepath.Join(tmpDir, "node_modules"))
 	if err != nil {
 		return err
 	}

cmd/setup-symlinks/internal/run_test.go

@@ -52,6 +52,7 @@ func testRun(t *testing.T, context spec.G, it spec.S) {
 	it.After(func() {
 		Expect(os.RemoveAll(layerDir)).To(Succeed())
 		Expect(os.RemoveAll(appDir)).To(Succeed())
+		Expect(os.RemoveAll(tmpDir)).To(Succeed())
 	})
 
 	it("creates a symlink to the node_modules dir in the layer", func() {
@@ -63,14 +64,31 @@ func testRun(t *testing.T, context spec.G, it spec.S) {
 		Expect(link).To(Equal(filepath.Join(layerDir, "node_modules")))
 	})
 
+	context("when the symlink already exists", func() {
+		it.Before(func() {
+			Expect(os.Symlink("some-location", filepath.Join(tmpDir, "node_modules"))).To(Succeed())
+		})
+
+		it("replaces it", func() {
+			err := internal.Run(executablePath, appDir, tmpDir)
+			Expect(err).NotTo(HaveOccurred())
+
+			link, err := os.Readlink(filepath.Join(tmpDir, "node_modules"))
+			Expect(err).NotTo(HaveOccurred())
+			Expect(link).To(Equal(filepath.Join(layerDir, "node_modules")))
+		})
+	})
+
 	context("failure cases", func() {
 		context("when the tmp dir node_modules cannot be removed", func() {
 			it.Before(func() {
 				Expect(os.Chmod(tmpDir, 0444)).To(Succeed())
 			})
+
 			it.After(func() {
 				Expect(os.Chmod(tmpDir, os.ModePerm)).To(Succeed())
 			})
+
 			it("returns an error", func() {
 				err := internal.Run(executablePath, appDir, tmpDir)
 				Expect(err).To(MatchError(ContainSubstring("permission denied")))

go.mod

@@ -5,7 +5,7 @@ go 1.16
 require (
 	github.com/BurntSushi/toml v1.2.0
 	github.com/onsi/gomega v1.20.0
-	github.com/paketo-buildpacks/occam v0.9.0
+	github.com/paketo-buildpacks/occam v0.11.0
 	github.com/paketo-buildpacks/packit/v2 v2.3.1
 	github.com/sclevine/spec v1.4.0
 )

integration/init_test.go

@@ -13,6 +13,7 @@ import (
 	"github.com/sclevine/spec/report"
 
 	. "github.com/onsi/gomega"
+	"github.com/onsi/gomega/format"
 )
 
 var (
@@ -31,6 +32,9 @@ var (
 )
 
 func TestIntegration(t *testing.T) {
+	format.MaxLength = 0
+	SetDefaultEventuallyTimeout(30 * time.Second)
+
 	var (
 		Expect = NewWithT(t).Expect
 		err    error
@@ -84,22 +88,21 @@ func TestIntegration(t *testing.T) {
 
 	npmList = filepath.Join(root, "integration", "testdata", "npm-list-buildpack")
 
-	SetDefaultEventuallyTimeout(10 * time.Second)
-
 	suite := spec.New("Integration", spec.Parallel(), spec.Report(report.Terminal{}))
 	suite("Caching", testCaching)
 	suite("DevDependenciesDuringBuild", testDevDependenciesDuringBuild)
 	suite("EmptyNodeModules", testEmptyNodeModules)
 	suite("Logging", testLogging)
 	suite("NoNodeModules", testNoNodeModules)
 	suite("Npmrc", testNpmrc)
+	suite("PackageLockMismatch", testPackageLockMismatch)
 	suite("PrePostScriptsRebuild", testPrePostScriptRebuild)
+	suite("ProjectPath", testProjectPath)
+	suite("Restart", testRestart)
 	suite("SimpleApp", testSimpleApp)
 	suite("UnmetDependencies", testUnmetDependencies)
 	suite("Vendored", testVendored)
 	suite("VendoredWithBinaries", testVendoredWithBinaries)
 	suite("Versioning", testVersioning)
-	suite("PackageLockMismatch", testPackageLockMismatch)
-	suite("ProjectPath", testProjectPath)
 	suite.Run(t)
 }

integration/restart_test.go

@@ -0,0 +1,83 @@
+package integration_test
+
+import (
+	"os"
+	"path/filepath"
+	"testing"
+
+	"github.com/paketo-buildpacks/occam"
+	"github.com/sclevine/spec"
+
+	. "github.com/onsi/gomega"
+	. "github.com/paketo-buildpacks/occam/matchers"
+)
+
+func testRestart(t *testing.T, context spec.G, it spec.S) {
+	var (
+		Expect     = NewWithT(t).Expect
+		Eventually = NewWithT(t).Eventually
+
+		pack   occam.Pack
+		docker occam.Docker
+
+		image     occam.Image
+		container occam.Container
+
+		name    string
+		source  string
+		sbomDir string
+	)
+
+	it.Before(func() {
+		pack = occam.NewPack()
+		docker = occam.NewDocker()
+
+		var err error
+		name, err = occam.RandomName()
+		Expect(err).NotTo(HaveOccurred())
+
+		sbomDir, err = os.MkdirTemp("", "sbom")
+		Expect(err).NotTo(HaveOccurred())
+		Expect(os.Chmod(sbomDir, os.ModePerm)).To(Succeed())
+	})
+
+	it.After(func() {
+		Expect(docker.Container.Remove.Execute(container.ID)).To(Succeed())
+		Expect(docker.Image.Remove.Execute(image.ID)).To(Succeed())
+		Expect(docker.Volume.Remove.Execute(occam.CacheVolumeNames(name))).To(Succeed())
+		Expect(os.RemoveAll(source)).To(Succeed())
+		Expect(os.RemoveAll(sbomDir)).To(Succeed())
+	})
+
+	it("allows the process to be restarted", func() {
+		var err error
+		source, err = occam.Source(filepath.Join("testdata", "simple_app"))
+		Expect(err).NotTo(HaveOccurred())
+
+		image, _, err = pack.Build.
+			WithBuildpacks(nodeURI, buildpackURI, buildPlanURI).
+			WithPullPolicy("never").
+			WithSBOMOutputDir(sbomDir).
+			Execute(name, source)
+		Expect(err).NotTo(HaveOccurred())
+
+		container, err = docker.Container.Run.
+			WithDirect().
+			WithCommand("node").
+			WithCommandArgs([]string{"server.js"}).
+			WithEnv(map[string]string{"PORT": "8080"}).
+			WithPublish("8080:8080").
+			Execute(image.ID)
+		Expect(err).NotTo(HaveOccurred())
+
+		Eventually(container).Should(Serve("Hello World!"), func() string {
+			logs, _ := docker.Container.Logs.Execute(container.ID)
+			return logs.String()
+		})
+
+		err = docker.Container.Restart.Execute(container.ID)
+		Expect(err).NotTo(HaveOccurred())
+
+		Eventually(container).Should(Serve("Hello World!"))
+	})
+}

integration/testdata/simple_app/server.js

@@ -1,12 +1,18 @@
 const http = require('http');
 const leftpad = require('leftpad');
 
-const port = process.env.PORT || 8080;
-
 const server = http.createServer((request, response) => {
-  response.end(JSON.stringify(process.env))
+  switch (request.url) {
+    case '/process':
+      response.end(JSON.stringify(process.env))
+      break;
+
+    default:
+      response.end('Hello World!');
+  }
 });
 
+const port = process.env.PORT || 8080;
 server.listen(port, (err) => {
   if (err) {
     return console.log('something bad happened', err);