Improve modules and subsystems packages

modules/flags.go

@@ -1,14 +1,19 @@
 package modules
 
-import "flag"
+import (
+	"flag"
+	"fmt"
+)
 
 var (
 	// HelpFlag triggers printing flag.Usage. It's exported for custom help handling.
-	HelpFlag bool
+	HelpFlag       bool
+	printGraphFlag bool
 )
 
 func init() {
 	flag.BoolVar(&HelpFlag, "help", false, "print help")
+	flag.BoolVar(&printGraphFlag, "print-module-graph", false, "print the module dependency graph")
 }
 
 func parseFlags() error {
@@ -20,5 +25,36 @@ func parseFlags() error {
 		return ErrCleanExit
 	}
 
+	if printGraphFlag {
+		printGraph()
+		return ErrCleanExit
+	}
+
 	return nil
 }
+
+func printGraph() {
+	// mark roots
+	for _, module := range modules {
+		if len(module.depReverse) == 0 {
+			// is root, dont print deps in dep tree
+			module.stopFlag.Set()
+		}
+	}
+	// print
+	for _, module := range modules {
+		if module.stopFlag.IsSet() {
+			// print from root
+			printModuleGraph("", module, true)
+		}
+	}
+}
+
+func printModuleGraph(prefix string, module *Module, root bool) {
+	fmt.Printf("%s├── %s\n", prefix, module.Name)
+	if root || !module.stopFlag.IsSet() {
+		for _, dep := range module.Dependencies() {
+			printModuleGraph(fmt.Sprintf("│   %s", prefix), dep, false)
+		}
+	}
+}

modules/start.go

@@ -48,7 +48,9 @@ func Start() error {
 	// parse flags
 	err = parseFlags()
 	if err != nil {
-		fmt.Fprintf(os.Stderr, "CRITICAL ERROR: failed to parse flags: %s\n", err)
+		if err != ErrCleanExit {
+			fmt.Fprintf(os.Stderr, "CRITICAL ERROR: failed to parse flags: %s\n", err)
+		}
 		return err
 	}
 
@@ -92,7 +94,11 @@ func Start() error {
 	}
 
 	// complete startup
-	log.Infof("modules: started %d modules", len(modules))
+	if moduleMgmtEnabled.IsSet() {
+		log.Info("modules: initiated subsystems manager")
+	} else {
+		log.Infof("modules: started %d modules", len(modules))
+	}
 
 	go taskQueueHandler()
 	go taskScheduleHandler()

modules/stop.go

@@ -16,6 +16,11 @@ var (
 	shutdownCompleteSignal = make(chan struct{})
 )
 
+// IsShuttingDown returns whether the global shutdown is in progress.
+func IsShuttingDown() bool {
+	return shutdownFlag.IsSet()
+}
+
 // ShuttingDown returns a channel read on the global shutdown signal.
 func ShuttingDown() <-chan struct{} {
 	return shutdownSignal

modules/subsystems/module.go

@@ -1,6 +1,9 @@
 package subsystems
 
 import (
+	"context"
+	"flag"
+	"fmt"
 	"strings"
 
 	"github.com/safing/portbase/database"
@@ -14,7 +17,8 @@ const (
 )
 
 var (
-	module *modules.Module
+	module         *modules.Module
+	printGraphFlag bool
 
 	databaseKeySpace string
 	db               = database.NewInterface(nil)
@@ -30,9 +34,16 @@ func init() {
 
 	// register event for changes in the subsystem
 	module.RegisterEvent(subsystemsStatusChange)
+
+	flag.BoolVar(&printGraphFlag, "print-subsystem-graph", false, "print the subsystem module dependency graph")
 }
 
 func prep() error {
+	if printGraphFlag {
+		printGraph()
+		return modules.ErrCleanExit
+	}
+
 	return module.RegisterEventHook("config", configChangeEvent, "control subsystems", handleConfigChanges)
 }
 
@@ -54,7 +65,10 @@ func start() error {
 	subsystemsLock.Unlock()
 
 	// apply config
-	return handleConfigChanges(module.Ctx, nil)
+	module.StartWorker("initial subsystem configuration", func(ctx context.Context) error {
+		return handleConfigChanges(module.Ctx, nil)
+	})
+	return nil
 }
 
 func (sub *Subsystem) addDependencies(module *modules.Module, seen map[string]struct{}) {
@@ -81,3 +95,23 @@ func SetDatabaseKeySpace(keySpace string) {
 		}
 	}
 }
+
+func printGraph() {
+	// mark roots
+	for _, sub := range subsystems {
+		sub.module.Enable() // mark as tree root
+	}
+	// print
+	for _, sub := range subsystems {
+		printModuleGraph("", sub.module, true)
+	}
+}
+
+func printModuleGraph(prefix string, module *modules.Module, root bool) {
+	fmt.Printf("%s├── %s\n", prefix, module.Name)
+	if root || !module.Enabled() {
+		for _, dep := range module.Dependencies() {
+			printModuleGraph(fmt.Sprintf("│   %s", prefix), dep, false)
+		}
+	}
+}

modules/subsystems/subsystem.go

@@ -14,6 +14,7 @@ type Subsystem struct { //nolint:maligned // not worth the effort
 	record.Base
 	sync.Mutex
 
+	ID          string
 	Name        string
 	Description string
 	module      *modules.Module
@@ -22,7 +23,7 @@ type Subsystem struct { //nolint:maligned // not worth the effort
 	Dependencies  []*ModuleStatus
 	FailureStatus uint8
 
-	ToggleOptionKey string // empty == forced on
+	ToggleOptionKey string
 	toggleOption    *config.Option
 	toggleValue     func() bool
 	ExpertiseLevel  uint8 // copied from toggleOption
@@ -49,7 +50,9 @@ type ModuleStatus struct {
 // Save saves the Subsystem Status to the database.
 func (sub *Subsystem) Save() {
 	if databaseKeySpace != "" {
-		// sub.SetKey() // FIXME
+		if !sub.KeyIsSet() {
+			sub.SetKey(databaseKeySpace + sub.ID)
+		}
 		err := db.Put(sub)
 		if err != nil {
 			log.Errorf("subsystems: could not save subsystem status to database: %s", err)

modules/subsystems/subsystems.go

@@ -2,7 +2,6 @@ package subsystems
 
 import (
 	"context"
-	"errors"
 	"fmt"
 	"sync"
 	"time"
@@ -22,25 +21,26 @@ var (
 	handlingConfigChanges = abool.New()
 )
 
-// Register registers a new subsystem. The given option must be a bool option. Should be called in the module's prep function. The config option must not yet be registered and will be registered for you.
-func Register(name, description string, module *modules.Module, configKeySpace string, option *config.Option) error {
+// Register registers a new subsystem. The given option must be a bool option. Should be called in init() directly after the modules.Register() function. The config option must not yet be registered and will be registered for you. Pass a nil option to force enable.
+func Register(id, name, description string, module *modules.Module, configKeySpace string, option *config.Option) {
 	// lock slice and map
 	subsystemsLock.Lock()
 	defer subsystemsLock.Unlock()
 
 	// check if registration is closed
 	if subsystemsLocked.IsSet() {
-		return errors.New("subsystems can only be registered in prep phase")
+		panic("subsystems can only be registered in prep phase or earlier")
 	}
 
 	// check if already registered
 	_, ok := subsystemsMap[name]
 	if ok {
-		return fmt.Errorf(`subsystem "%s" already registered`, name)
+		panic(fmt.Sprintf(`subsystem "%s" already registered`, name))
 	}
 
 	// create new
 	new := &Subsystem{
+		ID:          id,
 		Name:        name,
 		Description: description,
 		module:      module,
@@ -60,16 +60,17 @@ func Register(name, description string, module *modules.Module, configKeySpace s
 	if option != nil {
 		err := config.Register(option)
 		if err != nil {
-			return fmt.Errorf("failed to register config: %s", err)
+			panic(fmt.Sprintf("failed to register config: %s", err))
 		}
+		new.toggleValue = config.GetAsBool(new.ToggleOptionKey, false)
+	} else {
+		// force enabled
+		new.toggleValue = func() bool { return true }
 	}
-	new.toggleValue = config.GetAsBool(new.ToggleOptionKey, false)
 
 	// add to lists
 	subsystemsMap[name] = new
 	subsystems = append(subsystems, new)
-
-	return nil
 }
 
 func handleModuleChanges(m *modules.Module) {
@@ -78,6 +79,11 @@ func handleModuleChanges(m *modules.Module) {
 		return
 	}
 
+	// check if shutting down
+	if modules.IsShuttingDown() {
+		return
+	}
+
 	// find module status
 	var moduleSubsystem *Subsystem
 	var moduleStatus *ModuleStatus