baseline: api+gui traffic mode + candidates picker

Snapshot before app-launcher (cgroup/mark) work; ignore binaries/backups.

selective-vpn-api/app/events_bus.go

@@ -0,0 +1,109 @@
+package app
+
+import (
+	"os"
+	"strconv"
+	"strings"
+	"sync"
+	"time"
+)
+
+// ---------------------------------------------------------------------
+// события / event bus
+// ---------------------------------------------------------------------
+
+// EN: In-memory bounded event bus used for SSE replay and polling watchers.
+// EN: It keeps only the latest N events and assigns monotonically increasing IDs.
+// RU: Ограниченная in-memory шина событий для SSE-реплея и фоновых вотчеров.
+// RU: Хранит только последние N событий и присваивает монотонно растущие ID.
+type eventBus struct {
+	mu   sync.Mutex
+	cond *sync.Cond
+	buf  []Event
+	cap  int
+	next int64
+}
+
+// ---------------------------------------------------------------------
+// EN: `newEventBus` creates a new instance for event bus.
+// RU: `newEventBus` - создает новый экземпляр для event bus.
+// ---------------------------------------------------------------------
+func newEventBus(capacity int) *eventBus {
+	if capacity < 16 {
+		capacity = 16
+	}
+	b := &eventBus{
+		cap: capacity,
+		buf: make([]Event, 0, capacity),
+	}
+	b.cond = sync.NewCond(&b.mu)
+	return b
+}
+
+// ---------------------------------------------------------------------
+// EN: `push` contains core logic for push.
+// RU: `push` - содержит основную логику для push.
+// ---------------------------------------------------------------------
+func (b *eventBus) push(kind string, data interface{}) Event {
+	b.mu.Lock()
+	defer b.mu.Unlock()
+
+	b.next++
+	evt := Event{
+		ID:   b.next,
+		Kind: kind,
+		Ts:   time.Now().UTC().Format(time.RFC3339Nano),
+		Data: data,
+	}
+
+	if len(b.buf) >= b.cap {
+		b.buf = b.buf[1:]
+	}
+	b.buf = append(b.buf, evt)
+	b.cond.Broadcast()
+	return evt
+}
+
+// ---------------------------------------------------------------------
+// EN: `since` contains core logic for since.
+// RU: `since` - содержит основную логику для since.
+// ---------------------------------------------------------------------
+func (b *eventBus) since(id int64) []Event {
+	b.mu.Lock()
+	defer b.mu.Unlock()
+	return b.sinceLocked(id)
+}
+
+// ---------------------------------------------------------------------
+// EN: `sinceLocked` contains core logic for since locked.
+// RU: `sinceLocked` - содержит основную логику для since locked.
+// ---------------------------------------------------------------------
+func (b *eventBus) sinceLocked(id int64) []Event {
+	if len(b.buf) == 0 {
+		return nil
+	}
+	var out []Event
+	for _, ev := range b.buf {
+		if ev.ID > id {
+			out = append(out, ev)
+		}
+	}
+	return out
+}
+
+// ---------------------------------------------------------------------
+// env helpers
+// ---------------------------------------------------------------------
+
+// EN: Positive integer env reader with safe default fallback.
+// RU: Чтение положительного целого из env с безопасным fallback на дефолт.
+func envInt(key string, def int) int {
+	if v := strings.TrimSpace(os.Getenv(key)); v != "" {
+		if n, err := strconv.Atoi(v); err == nil && n > 0 {
+			return n
+		}
+	}
+	return def
+}
+
+var events = newEventBus(envInt("SVPN_EVENTS_CAP", defaultEventsCapacity))