Handles build flags that contain whitespace (#26)

Resolves #23

build_configuration_parser.go

@@ -55,7 +55,7 @@ func (p BuildConfigurationParser) Parse(path string) ([]string, []string, error)
 
 	var buildFlags []string
 	for _, flag := range config.Go.Build.Flags {
-		buildFlags = append(buildFlags, strings.SplitN(flag, "=", 2)...)
+		buildFlags = append(buildFlags, splitFlags(flag)...)
 	}
 	config.Go.Build.Flags = buildFlags
 
@@ -72,3 +72,16 @@ func (p BuildConfigurationParser) Parse(path string) ([]string, []string, error)
 
 	return config.Go.Targets, config.Go.Build.Flags, nil
 }
+
+func splitFlags(flag string) []string {
+	parts := strings.SplitN(flag, "=", 2)
+	if len(parts) == 2 {
+		if len(parts[1]) >= 2 {
+			if c := parts[1][len(parts[1])-1]; parts[1][0] == c && (c == '"' || c == '\'') {
+				parts[1] = parts[1][1 : len(parts[1])-1]
+			}
+		}
+	}
+
+	return parts
+}

build_configuration_parser_test.go

@@ -34,6 +34,8 @@ go:
     - -first
     - value
     - -second=value
+    - -third="value"
+    - -fourth='value'
 `)
 		Expect(err).NotTo(HaveOccurred())
 
@@ -52,7 +54,12 @@ go:
 		targets, flags, err := parser.Parse(path)
 		Expect(err).NotTo(HaveOccurred())
 		Expect(targets).To(Equal([]string{"./first", "./second"}))
-		Expect(flags).To(Equal([]string{"-first", "value", "-second", "value"}))
+		Expect(flags).To(Equal([]string{
+			"-first", "value",
+			"-second", "value",
+			"-third", "value",
+			"-fourth", "value",
+		}))
 	})
 
 	context("when there is no buildpack.yml file", func() {
@@ -110,7 +117,12 @@ go:
 			targets, flags, err := parser.Parse(path)
 			Expect(err).NotTo(HaveOccurred())
 			Expect(targets).To(Equal([]string{"./some/target1", "./some/target2"}))
-			Expect(flags).To(Equal([]string{"-first", "value", "-second", "value"}))
+			Expect(flags).To(Equal([]string{
+				"-first", "value",
+				"-second", "value",
+				"-third", "value",
+				"-fourth", "value",
+			}))
 		})
 	})
 

go_build_process.go

@@ -6,8 +6,10 @@ import (
 	"fmt"
 	"os"
 	"path/filepath"
+	"strconv"
 	"strings"
 	"time"
+	"unicode"
 
 	"github.com/paketo-buildpacks/packit/chronos"
 	"github.com/paketo-buildpacks/packit/pexec"
@@ -79,7 +81,11 @@ func (p GoBuildProcess) Execute(config GoBuildConfiguration) (string, error) {
 		env = append(env, fmt.Sprintf("GOPATH=%s", config.GoPath))
 	}
 
-	p.logs.Subprocess("Running '%s'", strings.Join(append([]string{"go"}, args...), " "))
+	printedArgs := []string{"go"}
+	for _, arg := range args {
+		printedArgs = append(printedArgs, formatArg(arg))
+	}
+	p.logs.Subprocess("Running '%s'", strings.Join(printedArgs, " "))
 
 	buffer := bytes.NewBuffer(nil)
 	duration, err := p.clock.Measure(func() error {
@@ -112,3 +118,13 @@ func (p GoBuildProcess) Execute(config GoBuildConfiguration) (string, error) {
 
 	return paths[0], nil
 }
+
+func formatArg(arg string) string {
+	for _, r := range arg {
+		if unicode.IsSpace(r) {
+			return strconv.Quote(arg)
+		}
+	}
+
+	return arg
+}

go_build_process_test.go

@@ -161,7 +161,7 @@ func testGoBuildProcess(t *testing.T, context spec.G, it spec.S) {
 				Output:    filepath.Join(layerPath, "bin"),
 				GoCache:   goCache,
 				Targets:   []string{"."},
-				Flags:     []string{"-buildmode", "default", "-tags", "paketo", "-mod", "mod"},
+				Flags:     []string{"-buildmode", "default", "-ldflags", "-X main.variable=some-value", "-mod", "mod"},
 			})
 			Expect(err).NotTo(HaveOccurred())
 			Expect(command).To(Equal(filepath.Join(layerPath, "bin", "a_command")))
@@ -172,15 +172,15 @@ func testGoBuildProcess(t *testing.T, context spec.G, it spec.S) {
 				"build",
 				"-o", filepath.Join(layerPath, "bin"),
 				"-buildmode", "default",
-				"-tags", "paketo",
+				"-ldflags", "-X main.variable=some-value",
 				"-mod", "mod",
 				".",
 			}))
 			Expect(executable.ExecuteCall.Receives.Execution.Dir).To(Equal(workspacePath))
 			Expect(executable.ExecuteCall.Receives.Execution.Env).To(ContainElement(fmt.Sprintf("GOCACHE=%s", goCache)))
 
 			Expect(logs.String()).To(ContainSubstring("  Executing build process"))
-			Expect(logs.String()).To(ContainSubstring(fmt.Sprintf("    Running 'go build -o %s -buildmode default -tags paketo -mod mod .'", filepath.Join(layerPath, "bin"))))
+			Expect(logs.String()).To(ContainSubstring(fmt.Sprintf(`    Running 'go build -o %s -buildmode default -ldflags "-X main.variable=some-value" -mod mod .'`, filepath.Join(layerPath, "bin"))))
 			Expect(logs.String()).To(ContainSubstring("      Completed in 1s"))
 		})
 	})

integration/build_flags_test.go

@@ -79,12 +79,13 @@ func testBuildFlags(t *testing.T, context spec.G, it spec.S) {
 			content, err := ioutil.ReadAll(response.Body)
 			Expect(err).NotTo(HaveOccurred())
 			Expect(string(content)).To(ContainSubstring("go1.14"))
+			Expect(string(content)).To(ContainSubstring(`variable value: "some-value"`))
 			Expect(string(content)).To(ContainSubstring("/workspace contents: []"))
 
 			Expect(logs).To(ContainLines(
 				MatchRegexp(fmt.Sprintf(`%s \d+\.\d+\.\d+`, settings.Buildpack.Name)),
 				"  Executing build process",
-				fmt.Sprintf("    Running 'go build -o /layers/%s/targets/bin -buildmode default -tags paketo .'", strings.ReplaceAll(settings.Buildpack.ID, "/", "_")),
+				fmt.Sprintf("    Running 'go build -o /layers/%s/targets/bin -buildmode default -tags paketo -ldflags \"-X main.variable=some-value\" .'", strings.ReplaceAll(settings.Buildpack.ID, "/", "_")),
 				MatchRegexp(`      Completed in ([0-9]*(\.[0-9]*)?[a-z]+)+`),
 				"",
 				"  Assigning launch processes",

integration/testdata/build_flags/buildpack.yml

@@ -4,3 +4,4 @@ go:
     flags:
     - -buildmode=default
     - -tags=paketo
+    - -ldflags="-X main.variable=some-value"

integration/testdata/build_flags/main.go

@@ -9,9 +9,12 @@ import (
 	"runtime"
 )
 
+var variable string
+
 func main() {
 	http.HandleFunc("/", func(w http.ResponseWriter, r *http.Request) {
 		fmt.Fprintln(w, runtime.Version())
+		fmt.Fprintf(w, "variable value: %q\n", variable)
 
 		paths, _ := filepath.Glob("/workspace/*")
 		fmt.Fprintf(w, "/workspace contents: %v\n", paths)