fix: serialize persistent profile mutations

internal/profile/store_test.go

@@ -0,0 +1,141 @@
+package profile
+
+import (
+	"errors"
+	"os"
+	"os/exec"
+	"path/filepath"
+	"syscall"
+	"testing"
+	"time"
+)
+
+type fakeIdentityEnvironment struct {
+	current UserIdentity
+	users   map[string]UserIdentity
+	env     map[string]string
+}
+
+func (f fakeIdentityEnvironment) CurrentUser() (UserIdentity, error) { return f.current, nil }
+func (f fakeIdentityEnvironment) LookupUser(name string) (UserIdentity, error) {
+	identity, ok := f.users[name]
+	if !ok {
+		return UserIdentity{}, errors.New("not found")
+	}
+	return identity, nil
+}
+func (f fakeIdentityEnvironment) LookupEnv(name string) (string, bool) {
+	value, ok := f.env[name]
+	return value, ok
+}
+
+func TestFileStoreLockSerializesAcrossProcesses(t *testing.T) {
+	if path := os.Getenv("PROXYCTL_LOCK_HELPER_PATH"); path != "" {
+		store := NewFileStore(path)
+		_, err := store.Mutate(func(state State) (State, error) {
+			state.Profiles = append(state.Profiles, Profile{Name: "child"})
+			return state, nil
+		})
+		if err != nil {
+			t.Fatal(err)
+		}
+		return
+	}
+
+	path := filepath.Join(t.TempDir(), "proxyctl", "profiles.json")
+	store := NewFileStore(path)
+	if _, err := store.Mutate(func(state State) (State, error) { return state, nil }); err != nil {
+		t.Fatal(err)
+	}
+	lock, err := os.OpenFile(path+".lock", os.O_RDWR, 0o600)
+	if err != nil {
+		t.Fatal(err)
+	}
+	defer lock.Close()
+	if err := syscall.Flock(int(lock.Fd()), syscall.LOCK_EX); err != nil {
+		t.Fatal(err)
+	}
+
+	command := exec.Command(os.Args[0], "-test.run=^TestFileStoreLockSerializesAcrossProcesses$")
+	command.Env = append(os.Environ(), "PROXYCTL_LOCK_HELPER_PATH="+path)
+	done := make(chan error, 1)
+	go func() { done <- command.Run() }()
+	select {
+	case err := <-done:
+		t.Fatalf("child mutation did not wait for lock: %v", err)
+	case <-time.After(100 * time.Millisecond):
+	}
+	if err := syscall.Flock(int(lock.Fd()), syscall.LOCK_UN); err != nil {
+		t.Fatal(err)
+	}
+	select {
+	case err := <-done:
+		if err != nil {
+			t.Fatalf("child mutation after unlock: %v", err)
+		}
+	case <-time.After(5 * time.Second):
+		_ = command.Process.Kill()
+		t.Fatal("child mutation remained blocked after unlock")
+	}
+	state, err := store.Load()
+	if err != nil {
+		t.Fatal(err)
+	}
+	if len(state.Profiles) != 1 || state.Profiles[0].Name != "child" {
+		t.Fatalf("state after serialized child mutation = %#v", state)
+	}
+}
+
+func TestConfigPathUsesInvokingUserIdentityUnderSudo(t *testing.T) {
+	environment := fakeIdentityEnvironment{
+		current: UserIdentity{Username: "root", HomeDir: "/root"},
+		users:   map[string]UserIdentity{"alice": {Username: "alice", HomeDir: "/home/alice"}},
+		env: map[string]string{
+			"SUDO_USER":       "alice",
+			"XDG_CONFIG_HOME": "/home/alice/.xdg/config",
+		},
+	}
+	path, err := ConfigPathWith(environment)
+	if err != nil {
+		t.Fatal(err)
+	}
+	want := filepath.Join("/home/alice/.xdg/config", "proxyctl", "profiles.json")
+	if path != want {
+		t.Fatalf("configuration path = %q, want invoking user's XDG path %q", path, want)
+	}
+}
+
+func TestConfigPathDoesNotReuseRootXDGForInvokingUser(t *testing.T) {
+	environment := fakeIdentityEnvironment{
+		current: UserIdentity{Username: "root", HomeDir: "/root"},
+		users:   map[string]UserIdentity{"alice": {Username: "alice", HomeDir: "/home/alice"}},
+		env: map[string]string{
+			"SUDO_USER":       "alice",
+			"XDG_CONFIG_HOME": "/root/.config",
+		},
+	}
+	path, err := ConfigPathWith(environment)
+	if err != nil {
+		t.Fatal(err)
+	}
+	want := filepath.Join("/home/alice/.config", "proxyctl", "profiles.json")
+	if path != want {
+		t.Fatalf("configuration path = %q, want invoking user's fallback %q", path, want)
+	}
+}
+
+func TestConfigPathUsesRootForDirectRootLogin(t *testing.T) {
+	environment := fakeIdentityEnvironment{
+		current: UserIdentity{Username: "root", HomeDir: "/root"},
+		users:   map[string]UserIdentity{},
+		env:     map[string]string{"XDG_CONFIG_HOME": "/root/custom-config"},
+	}
+	path, err := ConfigPathWith(environment)
+	if err != nil {
+		t.Fatal(err)
+	}
+	want := filepath.Join("/root/custom-config", "proxyctl", "profiles.json")
+	if path != want {
+		t.Fatalf("configuration path = %q, want direct root path %q", path, want)
+	}
+}