Debug should report CNB_APP_DIR as working directory for buildpacks images

pkg/skaffold/debug/cnb.go

@@ -69,8 +69,16 @@ func updateForCNBImage(container *v1.Container, ic imageConfiguration, transform
 		return ContainerDebugConfiguration{}, "", fmt.Errorf("buildpacks metadata has no processes")
 	}
 
-	// The buildpacks launcher is retained as the entrypoint
+	// The CNB launcher is retained as the entrypoint.
 	ic, rewriter := adjustCommandLine(m, ic)
+
+	// The CNB launcher uses CNB_APP_DIR (defaults to /workspace) and ignores the image's working directory.
+	if appDir := ic.env["CNB_APP_DIR"]; appDir != "" {
+		ic.workingDir = appDir
+	} else {
+		ic.workingDir = "/workspace"
+	}
+
 	c, img, err := transformer(container, ic)
 
 	// Only rewrite the container.Args if set: some transforms only alter env vars,

pkg/skaffold/debug/cnb_test.go

@@ -49,6 +49,7 @@ func TestUpdateForCNBImage(t *testing.T) {
 		input       imageConfiguration
 		shouldErr   bool
 		expected    v1.Container
+		config      ContainerDebugConfiguration
 	}{
 		{
 			description: "error when missing build.metadata",
@@ -65,48 +66,70 @@ func TestUpdateForCNBImage(t *testing.T) {
 			input:       imageConfiguration{entrypoint: []string{"/cnb/lifecycle/launcher"}, arguments: []string{"--", "web", "arg1", "arg2"}, labels: map[string]string{"io.buildpacks.build.metadata": mdJSON}},
 			shouldErr:   false,
 			expected:    v1.Container{Args: []string{"--", "web", "arg1", "arg2"}},
+			config:      ContainerDebugConfiguration{WorkingDir: "/workspace"},
 		},
 		{
 			description: "defaults to web process when no process type",
 			input:       imageConfiguration{entrypoint: []string{"/cnb/lifecycle/launcher"}, labels: map[string]string{"io.buildpacks.build.metadata": mdJSON}},
 			shouldErr:   false,
 			expected:    v1.Container{Args: []string{"webProcess", "webArg1", "webArg2"}},
+			config:      ContainerDebugConfiguration{WorkingDir: "/workspace"},
 		},
 		{
 			description: "resolves to default 'web' process",
 			input:       imageConfiguration{entrypoint: []string{"/cnb/lifecycle/launcher"}, labels: map[string]string{"io.buildpacks.build.metadata": mdJSON}},
 			shouldErr:   false,
 			expected:    v1.Container{Args: []string{"webProcess", "webArg1", "webArg2"}},
+			config:      ContainerDebugConfiguration{WorkingDir: "/workspace"},
 		},
 		{
 			description: "CNB_PROCESS_TYPE=web",
 			input:       imageConfiguration{entrypoint: []string{"/cnb/lifecycle/launcher"}, env: map[string]string{"CNB_PROCESS_TYPE": "web"}, labels: map[string]string{"io.buildpacks.build.metadata": mdJSON}},
 			shouldErr:   false,
 			expected:    v1.Container{Args: []string{"webProcess", "webArg1", "webArg2"}},
+			config:      ContainerDebugConfiguration{WorkingDir: "/workspace"},
 		},
 		{
 			description: "CNB_PROCESS_TYPE=diag",
 			input:       imageConfiguration{entrypoint: []string{"/cnb/lifecycle/launcher"}, env: map[string]string{"CNB_PROCESS_TYPE": "diag"}, labels: map[string]string{"io.buildpacks.build.metadata": mdJSON}},
 			shouldErr:   false,
 			expected:    v1.Container{Args: []string{"diagProcess"}},
+			config:      ContainerDebugConfiguration{WorkingDir: "/workspace"},
 		},
 		{
 			description: "CNB_PROCESS_TYPE=direct",
 			input:       imageConfiguration{entrypoint: []string{"/cnb/lifecycle/launcher"}, env: map[string]string{"CNB_PROCESS_TYPE": "direct"}, labels: map[string]string{"io.buildpacks.build.metadata": mdJSON}},
 			shouldErr:   false,
 			expected:    v1.Container{Args: []string{"--", "command", "cmdArg1"}},
+			config:      ContainerDebugConfiguration{WorkingDir: "/workspace"},
 		},
 		{
 			description: "script command-line",
 			input:       imageConfiguration{entrypoint: []string{"/cnb/lifecycle/launcher"}, arguments: []string{"python main.py"}, labels: map[string]string{"io.buildpacks.build.metadata": mdJSON}},
 			shouldErr:   false,
 			expected:    v1.Container{Args: []string{"python main.py"}},
+			config:      ContainerDebugConfiguration{WorkingDir: "/workspace"},
 		},
 		{
 			description: "no process and no args",
 			input:       imageConfiguration{entrypoint: []string{"/cnb/lifecycle/launcher"}, labels: map[string]string{"io.buildpacks.build.metadata": mdndJSON}},
 			shouldErr:   false,
 			expected:    v1.Container{},
+			config:      ContainerDebugConfiguration{WorkingDir: "/workspace"},
+		},
+		{
+			description: "launcher ignores image's working dir",
+			input:       imageConfiguration{entrypoint: []string{"/cnb/lifecycle/launcher"}, labels: map[string]string{"io.buildpacks.build.metadata": mdndJSON}, workingDir: "/workdir"},
+			shouldErr:   false,
+			expected:    v1.Container{},
+			config:      ContainerDebugConfiguration{WorkingDir: "/workspace"},
+		},
+		{
+			description: "CNB_APP_DIR used if set",
+			input:       imageConfiguration{entrypoint: []string{"/cnb/lifecycle/launcher"}, labels: map[string]string{"io.buildpacks.build.metadata": mdndJSON}, env: map[string]string{"CNB_APP_DIR": "/appDir"}, workingDir: "/workdir"},
+			shouldErr:   false,
+			expected:    v1.Container{},
+			config:      ContainerDebugConfiguration{WorkingDir: "/appDir"},
 		},
 	}
 	for _, test := range tests {
@@ -115,17 +138,18 @@ func TestUpdateForCNBImage(t *testing.T) {
 		testutil.Run(t, test.description+" (args changed)", func(t *testutil.T) {
 			argsChangedTransform := func(c *v1.Container, ic imageConfiguration) (ContainerDebugConfiguration, string, error) {
 				c.Args = ic.arguments
-				return ContainerDebugConfiguration{}, "", nil
+				return ContainerDebugConfiguration{WorkingDir: ic.workingDir}, "", nil
 			}
 			copy := v1.Container{}
-			_, _, err := updateForCNBImage(&copy, test.input, argsChangedTransform)
+			c, _, err := updateForCNBImage(&copy, test.input, argsChangedTransform)
 			t.CheckErrorAndDeepEqual(test.shouldErr, err, test.expected, copy)
+			t.CheckErrorAndDeepEqual(test.shouldErr, err, test.config, c)
 		})
 
 		// Test that when the arguments are left unchanged, that the container is unchanged
 		testutil.Run(t, test.description+" (args unchanged)", func(t *testutil.T) {
 			argsUnchangedTransform := func(c *v1.Container, ic imageConfiguration) (ContainerDebugConfiguration, string, error) {
-				return ContainerDebugConfiguration{}, "", nil
+				return ContainerDebugConfiguration{WorkingDir: ic.workingDir}, "", nil
 			}
 
 			copy := v1.Container{}

pkg/skaffold/debug/transform.go

@@ -66,6 +66,7 @@ import (
 )
 
 // ContainerDebugConfiguration captures debugging information for a specific container.
+// This structure is serialized out and included in the pod metadata.
 type ContainerDebugConfiguration struct {
 	// Artifact is the corresponding artifact's image name used in the skaffold.yaml
 	Artifact string `json:"artifact,omitempty"`
@@ -222,7 +223,9 @@ func transformPodSpec(metadata *metav1.ObjectMeta, podSpec *v1.PodSpec, retrieve
 		// `err != nil` means that the container did not or could not be transformed
 		if configuration, requiredImage, err := transformContainer(container, imageConfig, portAlloc); err == nil {
 			configuration.Artifact = imageConfig.artifact
-			configuration.WorkingDir = imageConfig.workingDir
+			if configuration.WorkingDir == "" {
+				configuration.WorkingDir = imageConfig.workingDir
+			}
 			configurations[container.Name] = configuration
 			if len(requiredImage) > 0 {
 				logrus.Infof("%q requires debugging support image %q", container.Name, requiredImage)