Use libreload-packit to handle live reload

paketo-buildpacks · Sep 19, 2022 · 1854478 · 1854478
1 parent 43f870f
commit 1854478
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Showing 7 changed files with 77 additions and 83 deletions.
diff --git a/build.go b/build.go
@@ -3,11 +3,12 @@ package nodestart
 import (
 	"os"
 
+	"github.com/paketo-buildpacks/libreload-packit"
 	"github.com/paketo-buildpacks/packit/v2"
 	"github.com/paketo-buildpacks/packit/v2/scribe"
 )
 
-func Build(applicationFinder ApplicationFinder, logger scribe.Emitter) packit.BuildFunc {
+func Build(applicationFinder ApplicationFinder, logger scribe.Emitter, reloader Reloader) packit.BuildFunc {
 	return func(context packit.BuildContext) (packit.BuildResult, error) {
 		logger.Title("%s %s", context.BuildpackInfo.Name, context.BuildpackInfo.Version)
 
@@ -16,46 +17,26 @@ func Build(applicationFinder ApplicationFinder, logger scribe.Emitter) packit.Bu
 			return packit.BuildResult{}, err
 		}
 
-		command := "node"
-		args := []string{file}
-
-		processes := []packit.Process{
-			{
-				Type:    "web",
-				Command: command,
-				Args:    args,
-				Default: true,
-				Direct:  true,
-			},
+		originalProcess := packit.Process{
+			Type:    "web",
+			Command: "node",
+			Args:    []string{file},
+			Default: true,
+			Direct:  true,
 		}
 
-		shouldReload, err := checkLiveReloadEnabled()
-		if err != nil {
+		var processes []packit.Process
+		if shouldEnableReload, err := reloader.ShouldEnableLiveReload(); err != nil {
 			return packit.BuildResult{}, err
-		}
-
-		if shouldReload {
-			processes = []packit.Process{
-				{
-					Type:    "web",
-					Command: "watchexec",
-					Args: append([]string{
-						"--restart",
-						"--watch", context.WorkingDir,
-						"--shell", "none",
-						"--",
-						command,
-					}, args...),
-					Direct:  true,
-					Default: true,
-				},
-				{
-					Type:    "no-reload",
-					Command: command,
-					Args:    args,
-					Direct:  true,
-				},
-			}
+		} else if shouldEnableReload {
+			nonReloadableProcess, reloadableProcess := reloader.TransformReloadableProcesses(originalProcess, libreload.ReloadableProcessSpec{
+				WatchPaths: []string{context.WorkingDir},
+			})
+			reloadableProcess.Type = "web"
+			nonReloadableProcess.Type = "no-reload"
+			processes = append(processes, reloadableProcess, nonReloadableProcess)
+		} else {
+			processes = append(processes, originalProcess)
 		}
 
 		logger.LaunchProcesses(processes)

diff --git a/build_test.go b/build_test.go
@@ -3,9 +3,9 @@ package nodestart_test
 import (
 	"bytes"
 	"errors"
-	"fmt"
 	"testing"
 
+	"github.com/paketo-buildpacks/libreload-packit"
 	nodestart "github.com/paketo-buildpacks/node-start"
 	"github.com/paketo-buildpacks/node-start/fakes"
 	"github.com/paketo-buildpacks/packit/v2"
@@ -25,6 +25,7 @@ func testBuild(t *testing.T, context spec.G, it spec.S) {
 		buffer     *bytes.Buffer
 
 		applicationFinder *fakes.ApplicationFinder
+		reloader          *fakes.Reloader
 
 		buildContext packit.BuildContext
 		build        packit.BuildFunc
@@ -38,6 +39,8 @@ func testBuild(t *testing.T, context spec.G, it spec.S) {
 		applicationFinder = &fakes.ApplicationFinder{}
 		applicationFinder.FindCall.Returns.String = "server.js"
 
+		reloader = &fakes.Reloader{}
+
 		buffer = bytes.NewBuffer(nil)
 		logger := scribe.NewEmitter(buffer)
 
@@ -54,7 +57,7 @@ func testBuild(t *testing.T, context spec.G, it spec.S) {
 			},
 			Layers: packit.Layers{Path: layersDir},
 		}
-		build = nodestart.Build(applicationFinder, logger)
+		build = nodestart.Build(applicationFinder, logger, reloader)
 	})
 
 	it("returns a result that provides a node start command", func() {
@@ -86,9 +89,17 @@ func testBuild(t *testing.T, context spec.G, it spec.S) {
 		Expect(buffer.String()).To(ContainSubstring("node server.js"))
 	})
 
-	context("when BP_LIVE_RELOAD_ENABLED=true in the build environment", func() {
+	context("when live reload is enabled", func() {
 		it.Before(func() {
-			t.Setenv("BP_LIVE_RELOAD_ENABLED", "true")
+			reloader.ShouldEnableLiveReloadCall.Returns.Bool = true
+			reloader.TransformReloadableProcessesCall.Returns.Reloadable = packit.Process{
+				Type:    "Reloadable",
+				Command: "Reloadable-Command",
+			}
+			reloader.TransformReloadableProcessesCall.Returns.NonReloadable = packit.Process{
+				Type:    "Nonreloadable",
+				Command: "Nonreloadable-Command",
+			}
 		})
 
 		it("adds a reloadable start command and makes it the default", func() {
@@ -98,29 +109,28 @@ func testBuild(t *testing.T, context spec.G, it spec.S) {
 			Expect(result.Launch.Processes).To(Equal([]packit.Process{
 				{
 					Type:    "web",
-					Command: "watchexec",
-					Args: []string{
-						"--restart",
-						"--watch", workingDir,
-						"--shell", "none",
-						"--",
-						"node", "server.js",
-					},
-					Default: true,
-					Direct:  true,
+					Command: "Reloadable-Command",
 				},
 				{
 					Type:    "no-reload",
-					Command: "node",
-					Args:    []string{"server.js"},
-					Direct:  true,
+					Command: "Nonreloadable-Command",
 				},
 			}))
 
+			Expect(reloader.TransformReloadableProcessesCall.Receives.OriginalProcess).To(Equal(packit.Process{
+				Type:    "web",
+				Command: "node",
+				Args:    []string{"server.js"},
+				Default: true,
+				Direct:  true,
+			}))
+
+			Expect(reloader.TransformReloadableProcessesCall.Receives.Spec).To(Equal(libreload.ReloadableProcessSpec{
+				WatchPaths: []string{workingDir},
+			}))
+
 			Expect(buffer.String()).To(ContainSubstring("Some Buildpack some-version"))
 			Expect(buffer.String()).To(ContainSubstring("Assigning launch processes"))
-			Expect(buffer.String()).To(ContainSubstring(fmt.Sprintf(`watchexec --restart --watch %s --shell none -- node server.js`, workingDir)))
-			Expect(buffer.String()).To(ContainSubstring("node server.js"))
 		})
 	})
 
@@ -135,14 +145,15 @@ func testBuild(t *testing.T, context spec.G, it spec.S) {
 				Expect(err).To(MatchError("failed to find application"))
 			})
 		})
-		context("when BP_LIVE_RELOAD_ENABLED is set to an invalid value", func() {
+
+		context("when the reloader returns an error", func() {
 			it.Before(func() {
-				t.Setenv("BP_LIVE_RELOAD_ENABLED", "not-a-bool")
+				reloader.ShouldEnableLiveReloadCall.Returns.Error = errors.New("reloader error")
 			})
 
 			it("returns an error", func() {
 				_, err := build(buildContext)
-				Expect(err).To(MatchError(ContainSubstring("failed to parse BP_LIVE_RELOAD_ENABLED value not-a-bool")))
+				Expect(err).To(MatchError("reloader error"))
 			})
 		})
 	})

diff --git a/detect.go b/detect.go
@@ -1,11 +1,10 @@
 package nodestart
 
 import (
-	"fmt"
 	"os"
 	"path/filepath"
-	"strconv"
 
+	"github.com/paketo-buildpacks/libreload-packit"
 	"github.com/paketo-buildpacks/packit/v2"
 	"github.com/paketo-buildpacks/packit/v2/fs"
 )
@@ -15,7 +14,11 @@ type ApplicationFinder interface {
 	Find(workingDir, launchpoint, projectPath string) (string, error)
 }
 
-func Detect(applicationFinder ApplicationFinder) packit.DetectFunc {
+type Reloader libreload.Reloader
+
+//go:generate faux --interface Reloader --output fakes/reloader.go
+
+func Detect(applicationFinder ApplicationFinder, reloader Reloader) packit.DetectFunc {
 	return func(context packit.DetectContext) (packit.DetectResult, error) {
 		_, err := applicationFinder.Find(context.WorkingDir, os.Getenv("BP_LAUNCHPOINT"), os.Getenv("BP_NODE_PROJECT_PATH"))
 		if err != nil {
@@ -30,7 +33,7 @@ func Detect(applicationFinder ApplicationFinder) packit.DetectFunc {
 			requirements = append(requirements, newLaunchRequirement("node_modules"))
 		}
 
-		if shouldReload, err := checkLiveReloadEnabled(); err != nil {
+		if shouldReload, err := reloader.ShouldEnableLiveReload(); err != nil {
 			return packit.DetectResult{}, err
 		} else if shouldReload {
 			requirements = append(requirements, newLaunchRequirement("watchexec"))
@@ -44,17 +47,6 @@ func Detect(applicationFinder ApplicationFinder) packit.DetectFunc {
 	}
 }
 
-func checkLiveReloadEnabled() (bool, error) {
-	if reload, ok := os.LookupEnv("BP_LIVE_RELOAD_ENABLED"); ok {
-		shouldEnableReload, err := strconv.ParseBool(reload)
-		if err != nil {
-			return false, fmt.Errorf("failed to parse BP_LIVE_RELOAD_ENABLED value %s: %w", reload, err)
-		}
-		return shouldEnableReload, nil
-	}
-	return false, nil
-}
-
 func newLaunchRequirement(name string) packit.BuildPlanRequirement {
 	return packit.BuildPlanRequirement{
 		Name: name,

diff --git a/detect_test.go b/detect_test.go
@@ -19,6 +19,7 @@ func testDetect(t *testing.T, context spec.G, it spec.S) {
 		Expect = NewWithT(t).Expect
 
 		applicationFinder *fakes.ApplicationFinder
+		reloader          *fakes.Reloader
 
 		detect     packit.DetectFunc
 		workingDir string
@@ -30,7 +31,9 @@ func testDetect(t *testing.T, context spec.G, it spec.S) {
 		applicationFinder = &fakes.ApplicationFinder{}
 		applicationFinder.FindCall.Returns.String = "./src/server.js"
 
-		detect = nodestart.Detect(applicationFinder)
+		reloader = &fakes.Reloader{}
+
+		detect = nodestart.Detect(applicationFinder, reloader)
 	})
 
 	context("when an application is detected in the working dir", func() {
@@ -62,9 +65,9 @@ func testDetect(t *testing.T, context spec.G, it spec.S) {
 			Expect(applicationFinder.FindCall.Receives.ProjectPath).To(Equal("./src"))
 		})
 
-		context("when BP_LIVE_RELOAD_ENABLED=true", func() {
+		context("when live reload is enabled", func() {
 			it.Before(func() {
-				t.Setenv("BP_LIVE_RELOAD_ENABLED", "true")
+				reloader.ShouldEnableLiveReloadCall.Returns.Bool = true
 			})
 
 			it("requires watchexec at launch time", func() {
@@ -150,16 +153,16 @@ func testDetect(t *testing.T, context spec.G, it spec.S) {
 			})
 		})
 
-		context("when BP_LIVE_RELOAD_ENABLED is set to an invalid value", func() {
+		context("when the reloader returns an error", func() {
 			it.Before(func() {
-				t.Setenv("BP_LIVE_RELOAD_ENABLED", "not-a-bool")
+				reloader.ShouldEnableLiveReloadCall.Returns.Error = errors.New("reloader error")
 			})
 
 			it("returns an error", func() {
 				_, err := detect(packit.DetectContext{
 					WorkingDir: workingDir,
 				})
-				Expect(err).To(MatchError(ContainSubstring("failed to parse BP_LIVE_RELOAD_ENABLED value not-a-bool")))
+				Expect(err).To(MatchError("reloader error"))
 			})
 		}, spec.Sequential())
 	})

diff --git a/go.mod b/go.mod
@@ -38,6 +38,7 @@ require (
 	github.com/opencontainers/go-digest v1.0.0 // indirect
 	github.com/opencontainers/image-spec v1.0.3-0.20220114050600-8b9d41f48198 // indirect
 	github.com/opencontainers/runc v1.1.4 // indirect
+	github.com/paketo-buildpacks/libreload-packit v0.0.1 // indirect
 	github.com/pelletier/go-toml v1.9.5 // indirect
 	github.com/pkg/errors v0.9.1 // indirect
 	github.com/sirupsen/logrus v1.9.0 // indirect

diff --git a/go.sum b/go.sum
@@ -1731,6 +1731,8 @@ github.com/otiai10/curr v1.0.0/go.mod h1:LskTG5wDwr8Rs+nNQ+1LlxRjAtTZZjtJW4rMXl6
 github.com/otiai10/mint v1.3.0/go.mod h1:F5AjcsTsWUqX+Na9fpHb52P8pcRX2CI6A3ctIT91xUo=
 github.com/otiai10/mint v1.3.1/go.mod h1:/yxELlJQ0ufhjUwhshSj+wFjZ78CnZ48/1wtmBH1OTc=
 github.com/pact-foundation/pact-go v1.0.4/go.mod h1:uExwJY4kCzNPcHRj+hCR/HBbOOIwwtUjcrb0b5/5kLM=
+github.com/paketo-buildpacks/libreload-packit v0.0.1 h1:K1HhNAqBSzRpefwGOcvdchZwyeNTgNJL9SC7V4paYt8=
+github.com/paketo-buildpacks/libreload-packit v0.0.1/go.mod h1:ZWE3U94Z18yJk8Pc1mP852l9phQsrsZ+An2U98g0rWw=
 github.com/paketo-buildpacks/occam v0.13.1 h1:qqkzCsxKkaeC64gC3555+qWTvqSS5kDgLMY9lct2rSQ=
 github.com/paketo-buildpacks/occam v0.13.1/go.mod h1:Mm7Do1u4au2qIUXd1XVeBQRFdLXI/yCdMns5J9Nph34=
 github.com/paketo-buildpacks/packit/v2 v2.1.0/go.mod h1:Ud1X7f9O6e4eGPZlY3pj0jnSa9oDK2L/ghvjmarTLSA=

diff --git a/run/main.go b/run/main.go
@@ -3,6 +3,7 @@ package main
 import (
 	"os"
 
+	"github.com/paketo-buildpacks/libreload-packit/watchexec"
 	nodestart "github.com/paketo-buildpacks/node-start"
 	"github.com/paketo-buildpacks/packit/v2"
 	"github.com/paketo-buildpacks/packit/v2/scribe"
@@ -11,12 +12,15 @@ import (
 func main() {
 	nodeApplicationFinder := nodestart.NewNodeApplicationFinder()
 	logger := scribe.NewEmitter(os.Stdout).WithLevel(os.Getenv("BP_LOG_LEVEL"))
-
+
+	reloader := watchexec.NewWatchexecReloader()
+
 	packit.Run(
-		nodestart.Detect(nodeApplicationFinder),
+		nodestart.Detect(nodeApplicationFinder, reloader),
 		nodestart.Build(
 			nodeApplicationFinder,
 			logger,
+			reloader,
 		),
 	)
 }