Use workspace modules with BP_GO_WORK_USE

Signed-off-by: Max Brauer <mbrauer@vmware.com>

README.md

@@ -61,6 +61,16 @@ imports its own sub-packages.
 BP_GO_BUILD_IMPORT_PATH= example.com/some-app
 ```
 
+### `BP_GO_WORK_USE`
+The `BP_GO_WORK_USE` variable allows you to initialise a workspace file and add
+modules to it. This is helpful for building submodules which use relative
+replace directives and `go.work` is not checked in. Usually, this is set
+together with `BP_GO_TARGETS`.
+
+```shell
+BP_GO_WORK_USE=./cmd/controller:./cmd/webhook
+```
+
 ### `BP_KEEP_FILES`
 The `BP_KEEP_FILES` variable allows to you to specity a path list of files
 (including file globs) that you would like to appear in the workspace of the

build.go

@@ -76,12 +76,13 @@ func Build(
 		}
 
 		config := GoBuildConfiguration{
-			Workspace: path,
-			Output:    filepath.Join(targetsLayer.Path, "bin"),
-			GoPath:    goPath,
-			GoCache:   goCacheLayer.Path,
-			Flags:     configuration.Flags,
-			Targets:   configuration.Targets,
+			Workspace:           path,
+			Output:              filepath.Join(targetsLayer.Path, "bin"),
+			GoPath:              goPath,
+			GoCache:             goCacheLayer.Path,
+			Flags:               configuration.Flags,
+			Targets:             configuration.Targets,
+			WorkspaceUseModules: configuration.WorkspaceUseModules,
 		}
 
 		if isStaticStack(context.Stack) && !containsFlag(config.Flags, "-buildmode") {

build_configuration_parser.go

@@ -17,9 +17,10 @@ type TargetManager interface {
 }
 
 type BuildConfiguration struct {
-	Targets    []string
-	Flags      []string
-	ImportPath string
+	Targets             []string
+	Flags               []string
+	ImportPath          string
+	WorkspaceUseModules []string
 }
 
 type BuildConfigurationParser struct {
@@ -67,6 +68,10 @@ func (p BuildConfigurationParser) Parse(buildpackVersion, workingDir string) (Bu
 		buildConfiguration.ImportPath = val
 	}
 
+	if val, ok := os.LookupEnv("BP_GO_WORK_USE"); ok {
+		buildConfiguration.WorkspaceUseModules = filepath.SplitList(val)
+	}
+
 	return buildConfiguration, nil
 }
 

build_configuration_parser_test.go

@@ -195,6 +195,27 @@ func testBuildConfigurationParser(t *testing.T, context spec.G, it spec.S) {
 		})
 	})
 
+	context("when BP_GO_WORK_USE is set", func() {
+		it.Before(func() {
+			os.Setenv("BP_GO_WORK_USE", "./some/module1:./some/module2")
+		})
+
+		it.After(func() {
+			os.Unsetenv("BP_GO_WORK_USE")
+		})
+
+		it("uses the values in the env var", func() {
+			configuration, err := parser.Parse("1.2.3", workingDir)
+			Expect(err).NotTo(HaveOccurred())
+			Expect(configuration).To(Equal(gobuild.BuildConfiguration{
+				Targets:             []string{"."},
+				WorkspaceUseModules: []string{"./some/module1", "./some/module2"},
+			}))
+
+			Expect(targetManager.GenerateDefaultsCall.Receives.WorkingDir).To(Equal(workingDir))
+		})
+	})
+
 	context("failure cases", func() {
 		context("when the working directory contains a buildpack.yml", func() {
 			it.Before(func() {

go_build_process.go

@@ -23,13 +23,14 @@ type Executable interface {
 }
 
 type GoBuildConfiguration struct {
-	Workspace  string
-	Output     string
-	GoPath     string
-	GoCache    string
-	Targets    []string
-	Flags      []string
-	DisableCGO bool
+	Workspace           string
+	Output              string
+	GoPath              string
+	GoCache             string
+	Targets             []string
+	Flags               []string
+	DisableCGO          bool
+	WorkspaceUseModules []string
 }
 
 type GoBuildProcess struct {
@@ -75,6 +76,44 @@ func (p GoBuildProcess) Execute(config GoBuildConfiguration) ([]string, error) {
 		env = append(env, "CGO_ENABLED=0")
 	}
 
+	if len(config.WorkspaceUseModules) > 0 {
+		// go work init
+		workInitArgs := []string{"work", "init"}
+		p.logs.Subprocess("Running '%s'", strings.Join(append([]string{"go"}, workInitArgs...), " "))
+
+		duration, err := p.clock.Measure(func() error {
+			return p.executable.Execute(pexec.Execution{
+				Args:   workInitArgs,
+				Dir:    config.Workspace,
+				Env:    env,
+				Stdout: p.logs.ActionWriter,
+				Stderr: p.logs.ActionWriter,
+			})
+		})
+		if err != nil {
+			p.logs.Action("Failed after %s", duration.Round(time.Millisecond))
+			return nil, fmt.Errorf("failed to execute '%s': %w", workInitArgs, err)
+		}
+
+		// go work use <modules...>
+		workUseArgs := append([]string{"work", "use"}, config.WorkspaceUseModules...)
+		p.logs.Subprocess("Running '%s'", strings.Join(append([]string{"go"}, workUseArgs...), " "))
+
+		duration, err = p.clock.Measure(func() error {
+			return p.executable.Execute(pexec.Execution{
+				Args:   workUseArgs,
+				Dir:    config.Workspace,
+				Env:    env,
+				Stdout: p.logs.ActionWriter,
+				Stderr: p.logs.ActionWriter,
+			})
+		})
+		if err != nil {
+			p.logs.Action("Failed after %s", duration.Round(time.Millisecond))
+			return nil, fmt.Errorf("failed to execute '%s': %w", workUseArgs, err)
+		}
+	}
+
 	printedArgs := []string{"go"}
 	for _, arg := range args {
 		printedArgs = append(printedArgs, formatArg(arg))

go_build_process_test.go

@@ -199,6 +199,66 @@ func testGoBuildProcess(t *testing.T, context spec.G, it spec.S) {
 		})
 	})
 
+	context("when workspaces should be used", func() {
+		it.Before(func() {
+			Expect(os.WriteFile(filepath.Join(workspacePath, "go.mod"), nil, 0644)).To(Succeed())
+			Expect(os.Mkdir(filepath.Join(workspacePath, "vendor"), os.ModePerm)).To(Succeed())
+		})
+
+		it("inits and uses the workspaces before executing the go build process", func() {
+			binaries, err := buildProcess.Execute(gobuild.GoBuildConfiguration{
+				Workspace:           workspacePath,
+				Output:              filepath.Join(layerPath, "bin"),
+				GoCache:             goCache,
+				Targets:             []string{"."},
+				WorkspaceUseModules: []string{"./some/module1", "./some/module2"},
+			})
+			Expect(err).NotTo(HaveOccurred())
+			Expect(binaries).To(Equal([]string{
+				filepath.Join(layerPath, "bin", "some-dir"),
+			}))
+
+			Expect(filepath.Join(layerPath, "bin")).To(BeADirectory())
+
+			Expect(executions[0].Args).To(Equal([]string{
+				"work",
+				"init",
+			}))
+
+			Expect(executions[1].Args).To(Equal([]string{
+				"work",
+				"use",
+				"./some/module1",
+				"./some/module2",
+			}))
+
+			Expect(executions[2].Args).To(Equal([]string{
+				"build",
+				"-o", filepath.Join(layerPath, "bin"),
+				"-buildmode", "pie",
+				"-trimpath",
+				".",
+			}))
+
+			Expect(executions[3].Args).To(Equal([]string{
+				"list",
+				"--json",
+				".",
+			}))
+
+			Expect(executable.ExecuteCall.Receives.Execution.Dir).To(Equal(workspacePath))
+			Expect(executable.ExecuteCall.Receives.Execution.Env).To(ContainElement(fmt.Sprintf("GOCACHE=%s", goCache)))
+
+			Expect(logs).To(ContainLines(
+				"  Executing build process",
+				"    Running 'go work init'",
+				"    Running 'go work use ./some/module1 ./some/module2'",
+				fmt.Sprintf(`    Running 'go build -o %s -buildmode pie -trimpath .'`, filepath.Join(layerPath, "bin")),
+				"      Completed in 0s",
+			))
+		})
+	})
+
 	context("when the GOPATH is empty", func() {
 		it.Before(func() {
 			Expect(os.WriteFile(filepath.Join(workspacePath, "go.mod"), nil, 0644)).To(Succeed())
@@ -244,6 +304,72 @@ func testGoBuildProcess(t *testing.T, context spec.G, it spec.S) {
 			})
 		})
 
+		context("when workspaces should be used", func() {
+			context("when the executable fails go work init", func() {
+				it.Before(func() {
+					executable.ExecuteCall.Stub = func(execution pexec.Execution) error {
+						if execution.Args[0] == "work" && execution.Args[1] == "init" {
+							fmt.Fprintln(execution.Stdout, "work init error stdout")
+							fmt.Fprintln(execution.Stderr, "work init error stderr")
+							return errors.New("command failed")
+						}
+
+						return nil
+					}
+				})
+
+				it("returns an error", func() {
+					_, err := buildProcess.Execute(gobuild.GoBuildConfiguration{
+						Workspace:           workspacePath,
+						Output:              filepath.Join(layerPath, "bin"),
+						GoPath:              goPath,
+						GoCache:             goCache,
+						Targets:             []string{"."},
+						WorkspaceUseModules: []string{"./some/module1", "./some/module2"},
+					})
+					Expect(err).To(MatchError("failed to execute '[work init]': command failed"))
+
+					Expect(logs).To(ContainLines(
+						"      work init error stdout",
+						"      work init error stderr",
+						"      Failed after 1s",
+					))
+				})
+			})
+
+			context("when the executable fails go work use", func() {
+				it.Before(func() {
+					executable.ExecuteCall.Stub = func(execution pexec.Execution) error {
+						if execution.Args[0] == "work" && execution.Args[1] == "use" {
+							fmt.Fprintln(execution.Stdout, "work use error stdout")
+							fmt.Fprintln(execution.Stderr, "work use error stderr")
+							return errors.New("command failed")
+						}
+
+						return nil
+					}
+				})
+
+				it("returns an error", func() {
+					_, err := buildProcess.Execute(gobuild.GoBuildConfiguration{
+						Workspace:           workspacePath,
+						Output:              filepath.Join(layerPath, "bin"),
+						GoPath:              goPath,
+						GoCache:             goCache,
+						Targets:             []string{"."},
+						WorkspaceUseModules: []string{"./some/module1", "./some/module2"},
+					})
+					Expect(err).To(MatchError("failed to execute '[work use ./some/module1 ./some/module2]': command failed"))
+
+					Expect(logs).To(ContainLines(
+						"      work use error stdout",
+						"      work use error stderr",
+						"      Failed after 0s",
+					))
+				})
+			})
+		})
+
 		context("when the executable fails go build", func() {
 			it.Before(func() {
 				executable.ExecuteCall.Stub = func(execution pexec.Execution) error {

integration/init_test.go

@@ -113,6 +113,7 @@ func TestIntegration(t *testing.T) {
 	suite("Rebuild", testRebuild)
 	suite("Targets", testTargets)
 	suite("Vendor", testVendor)
+	suite("WorkUse", testWorkUse)
 	if builder.BuilderName != "paketobuildpacks/builder-jammy-buildpackless-static" {
 		suite("BuildFlags", testBuildFlags)
 	}

integration/testdata/work_use/.gitignore

@@ -0,0 +1 @@
+go.work*

integration/testdata/work_use/cmd/cli/go.mod

@@ -0,0 +1,7 @@
+module github.com/paketo-buildpacks/go-build/integration/testdata/work_use/binary
+
+go 1.16
+
+replace github.com/paketo-buildpacks/go-build/integration/testdata/work_use => ../../
+
+require github.com/paketo-buildpacks/go-build/integration/testdata/work_use v0.0.0-00010101000000-000000000000

integration/testdata/work_use/cmd/cli/go.sum

@@ -0,0 +1,4 @@
+github.com/kylelemons/godebug v1.1.0 h1:RPNrshWIDI6G2gRW9EHilWtl7Z6Sb1BR0xunSBf0SNc=
+github.com/kylelemons/godebug v1.1.0/go.mod h1:9/0rRGxNHcop5bhtWyNeEfOS8JIWk580+fNqagV/RAw=
+github.com/sahilm/fuzzy v0.1.0 h1:FzWGaw2Opqyu+794ZQ9SYifWv2EIXpwP4q8dY1kDAwI=
+github.com/sahilm/fuzzy v0.1.0/go.mod h1:VFvziUEIMCrT6A6tw2RFIXPXXmzXbOsSHF0DOI8ZK9Y=

integration/testdata/work_use/cmd/cli/main.go

@@ -0,0 +1,13 @@
+package main
+
+import (
+	"fmt"
+
+	"github.com/paketo-buildpacks/go-build/integration/testdata/work_use/find"
+)
+
+func main() {
+	pattern := "buildpacks"
+	data := []string{"paketo", "buildpacks"}
+	fmt.Printf("found: %d", len(find.Fuzzy(pattern, data...)))
+}

integration/testdata/work_use/find/find.go

@@ -0,0 +1,13 @@
+package find
+
+import (
+	"github.com/sahilm/fuzzy"
+)
+
+func Fuzzy(pattern string, data ...string) []string {
+	var matches []string
+	for _, match := range fuzzy.Find(pattern, data) {
+		matches = append(matches, match.Str)
+	}
+	return matches
+}

integration/testdata/work_use/go.mod

@@ -0,0 +1,8 @@
+module github.com/paketo-buildpacks/go-build/integration/testdata/work_use
+
+go 1.16
+
+require (
+	github.com/kylelemons/godebug v1.1.0 // indirect
+	github.com/sahilm/fuzzy v0.1.0
+)

integration/testdata/work_use/go.sum

@@ -0,0 +1,4 @@
+github.com/kylelemons/godebug v1.1.0 h1:RPNrshWIDI6G2gRW9EHilWtl7Z6Sb1BR0xunSBf0SNc=
+github.com/kylelemons/godebug v1.1.0/go.mod h1:9/0rRGxNHcop5bhtWyNeEfOS8JIWk580+fNqagV/RAw=
+github.com/sahilm/fuzzy v0.1.0 h1:FzWGaw2Opqyu+794ZQ9SYifWv2EIXpwP4q8dY1kDAwI=
+github.com/sahilm/fuzzy v0.1.0/go.mod h1:VFvziUEIMCrT6A6tw2RFIXPXXmzXbOsSHF0DOI8ZK9Y=