feat(config): support custom workspaceMount from devcontainer.json

e2e/tests/up/provider_docker.go

@@ -528,6 +528,31 @@ var _ = ginkgo.Describe(
 				To(gomega.ContainElement("apparmor=unconfined"))
 		}, ginkgo.SpecTimeout(framework.TimeoutShort()))
 
+		ginkgo.It("custom workspace mount", func(ctx context.Context) {
+			tempDir, err := dtc.setupAndUp(ctx, "tests/up/testdata/docker-workspace-mount")
+			framework.ExpectNoError(err)
+
+			workspace, err := dtc.f.FindWorkspace(ctx, tempDir)
+			framework.ExpectNoError(err)
+
+			ids, err := dtc.findWorkspaceContainer(ctx, workspace)
+			framework.ExpectNoError(err)
+			gomega.Expect(ids).To(gomega.HaveLen(1))
+
+			var details []container.InspectResponse
+			err = dtc.dockerHelper.Inspect(ctx, ids, "container", &details)
+			framework.ExpectNoError(err)
+
+			hasCustomMount := false
+			for _, m := range details[0].Mounts {
+				if m.Destination == "/custom-workspace" {
+					hasCustomMount = true
+					break
+				}
+			}
+			gomega.Expect(hasCustomMount).To(gomega.BeTrue())
+		}, ginkgo.SpecTimeout(framework.TimeoutShort()))
+
 		ginkgo.It("multi devcontainer selection", func(ctx context.Context) {
 			tempDir, err := setupWorkspace(
 				"tests/up/testdata/docker-multi-devcontainer",

e2e/tests/up/testdata/docker-workspace-mount/.devcontainer.json

@@ -0,0 +1,6 @@
+{
+  "name": "Go",
+  "image": "ghcr.io/devsy-org/test-images/go:1",
+  "workspaceMount": "type=bind,source=${localWorkspaceFolder},target=/custom-workspace",
+  "workspaceFolder": "/custom-workspace"
+}

pkg/devcontainer/run_test.go

@@ -130,3 +130,71 @@ func searchString(s, substr string) bool {
 	}
 	return false
 }
+
+func TestGetWorkspace_CustomWorkspaceMount(t *testing.T) {
+	customMount := "type=bind,source=/host/src,target=/custom-ws"
+	conf := &config.DevContainerConfig{
+		NonComposeBase: config.NonComposeBase{
+			WorkspaceMount: customMount,
+		},
+	}
+
+	mount, folder := getWorkspace("/ignored", "ws-id", conf)
+
+	if mount != customMount {
+		t.Fatalf("expected raw workspaceMount string, got %q", mount)
+	}
+	if folder != "/custom-ws" {
+		t.Fatalf("expected target /custom-ws, got %q", folder)
+	}
+}
+
+func TestGetWorkspace_DefaultMount(t *testing.T) {
+	conf := &config.DevContainerConfig{}
+
+	mount, folder := getWorkspace("/home/user/project", "abc123", conf)
+
+	if !contains(mount, "type=bind") || !contains(mount, "source=/home/user/project") {
+		t.Fatalf("expected bind mount with source, got %q", mount)
+	}
+	if !contains(mount, "target=/workspaces/abc123") {
+		t.Fatalf("expected target /workspaces/abc123, got %q", mount)
+	}
+	if folder != "/workspaces/abc123" {
+		t.Fatalf("expected /workspaces/abc123, got %q", folder)
+	}
+}
+
+func TestGetWorkspace_DefaultMountWithWorkspaceFolder(t *testing.T) {
+	conf := &config.DevContainerConfig{
+		DevContainerConfigBase: config.DevContainerConfigBase{
+			WorkspaceFolder: "/app",
+		},
+	}
+
+	mount, folder := getWorkspace("/home/user/project", "ws-id", conf)
+
+	if !contains(mount, "type=bind") || !contains(mount, "target=/app") {
+		t.Fatalf("expected bind mount with target /app, got %q", mount)
+	}
+	if folder != "/app" {
+		t.Fatalf("expected /app, got %q", folder)
+	}
+}
+
+func TestGetWorkspace_EmptyWorkspaceMount(t *testing.T) {
+	conf := &config.DevContainerConfig{
+		NonComposeBase: config.NonComposeBase{
+			WorkspaceMount: "",
+		},
+	}
+
+	mount, folder := getWorkspace("/home/user/project", "ws-id", conf)
+
+	if folder != "/workspaces/ws-id" {
+		t.Fatalf("expected default folder, got %q", folder)
+	}
+	if !contains(mount, "type=bind") {
+		t.Fatalf("expected default bind mount, got %q", mount)
+	}
+}