v0.0.599 implement dataext.broadcaster

dataext/broadcaster.go

@@ -0,0 +1,230 @@
+package dataext
+
+import (
+	"context"
+	"iter"
+	"sync"
+	"time"
+
+	"git.blackforestbytes.com/BlackForestBytes/goext/langext"
+	"git.blackforestbytes.com/BlackForestBytes/goext/syncext"
+	"github.com/rs/xid"
+)
+
+// Broadcaster is a simple Broadcaster channel
+// This is a simpler interface over Broadcaster - which does not have distinct namespaces
+type Broadcaster[TData any] struct {
+	masterLock *sync.Mutex
+
+	subscriptions []*broadcastSubscription[TData]
+}
+
+type BroadcastSubscription interface {
+	Unsubscribe()
+}
+
+type broadcastSubscription[TData any] struct {
+	ID string
+
+	parent *Broadcaster[TData]
+
+	subLock *sync.Mutex
+
+	Func func(TData)
+	Chan chan TData
+
+	UnsubChan chan bool
+}
+
+func (p *broadcastSubscription[TData]) Unsubscribe() {
+	p.parent.unsubscribe(p)
+}
+
+func NewBroadcast[TData any](capacity int) *Broadcaster[TData] {
+	return &Broadcaster[TData]{
+		masterLock:    &sync.Mutex{},
+		subscriptions: make([]*broadcastSubscription[TData], 0, capacity),
+	}
+}
+
+func (bb *Broadcaster[TData]) SubscriberCount() int {
+	bb.masterLock.Lock()
+	defer bb.masterLock.Unlock()
+
+	return len(bb.subscriptions)
+}
+
+// Publish sends `data` to all subscriber
+// But unbuffered - if one is currently not listening, we skip (the actualReceiver < subscriber)
+func (bb *Broadcaster[TData]) Publish(data TData) (subscriber int, actualReceiver int) {
+	bb.masterLock.Lock()
+	subs := langext.ArrCopy(bb.subscriptions)
+	bb.masterLock.Unlock()
+
+	subscriber = len(subs)
+	actualReceiver = 0
+
+	for _, sub := range subs {
+		func() {
+			sub.subLock.Lock()
+			defer sub.subLock.Unlock()
+
+			if sub.Func != nil {
+				go func() { sub.Func(data) }()
+				actualReceiver++
+			} else if sub.Chan != nil {
+				msgSent := syncext.WriteNonBlocking(sub.Chan, data)
+				if msgSent {
+					actualReceiver++
+				}
+			}
+		}()
+	}
+
+	return subscriber, actualReceiver
+}
+
+// PublishWithContext sends `data` to all subscriber
+// buffered - if one is currently not listening, we wait (but error out when the context runs out)
+func (bb *Broadcaster[TData]) PublishWithContext(ctx context.Context, data TData) (subscriber int, actualReceiver int, err error) {
+	bb.masterLock.Lock()
+	subs := langext.ArrCopy(bb.subscriptions)
+	bb.masterLock.Unlock()
+
+	subscriber = len(subs)
+	actualReceiver = 0
+
+	for _, sub := range subs {
+		err := func() error {
+			sub.subLock.Lock()
+			defer sub.subLock.Unlock()
+
+			if err := ctx.Err(); err != nil {
+				return err
+			}
+
+			if sub.Func != nil {
+				go func() { sub.Func(data) }()
+				actualReceiver++
+			} else if sub.Chan != nil {
+				err := syncext.WriteChannelWithContext(ctx, sub.Chan, data)
+				if err != nil {
+					return err
+				}
+				actualReceiver++
+			}
+
+			return nil
+		}()
+		if err != nil {
+			return subscriber, actualReceiver, err
+		}
+	}
+
+	return subscriber, actualReceiver, nil
+}
+
+// PublishWithTimeout sends `data` to all subscriber
+// buffered - if one is currently not listening, we wait (but wait at most `timeout` - if the timeout is exceeded then actualReceiver < subscriber)
+func (bb *Broadcaster[TData]) PublishWithTimeout(data TData, timeout time.Duration) (subscriber int, actualReceiver int) {
+	bb.masterLock.Lock()
+	subs := langext.ArrCopy(bb.subscriptions)
+	bb.masterLock.Unlock()
+
+	subscriber = len(subs)
+	actualReceiver = 0
+
+	for _, sub := range subs {
+		func() {
+			sub.subLock.Lock()
+			defer sub.subLock.Unlock()
+
+			if sub.Func != nil {
+				go func() { sub.Func(data) }()
+				actualReceiver++
+			} else if sub.Chan != nil {
+				ok := syncext.WriteChannelWithTimeout(sub.Chan, data, timeout)
+				if ok {
+					actualReceiver++
+				}
+			}
+		}()
+	}
+
+	return subscriber, actualReceiver
+}
+
+func (bb *Broadcaster[TData]) SubscribeByCallback(fn func(TData)) BroadcastSubscription {
+	bb.masterLock.Lock()
+	defer bb.masterLock.Unlock()
+
+	sub := &broadcastSubscription[TData]{ID: xid.New().String(), parent: bb, subLock: &sync.Mutex{}, Func: fn, UnsubChan: nil}
+
+	bb.subscriptions = append(bb.subscriptions, sub)
+
+	return sub
+}
+
+func (bb *Broadcaster[TData]) SubscribeByChan(chanBufferSize int) (chan TData, BroadcastSubscription) {
+	bb.masterLock.Lock()
+	defer bb.masterLock.Unlock()
+
+	msgCh := make(chan TData, chanBufferSize)
+
+	sub := &broadcastSubscription[TData]{ID: xid.New().String(), parent: bb, subLock: &sync.Mutex{}, Chan: msgCh, UnsubChan: nil}
+
+	bb.subscriptions = append(bb.subscriptions, sub)
+
+	return msgCh, sub
+}
+
+func (bb *Broadcaster[TData]) SubscribeByIter(chanBufferSize int) (iter.Seq[TData], BroadcastSubscription) {
+	bb.masterLock.Lock()
+	defer bb.masterLock.Unlock()
+
+	msgCh := make(chan TData, chanBufferSize)
+	unsubChan := make(chan bool, 8)
+
+	sub := &broadcastSubscription[TData]{ID: xid.New().String(), parent: bb, subLock: &sync.Mutex{}, Chan: msgCh, UnsubChan: unsubChan}
+
+	bb.subscriptions = append(bb.subscriptions, sub)
+
+	iterFun := func(yield func(TData) bool) {
+		for {
+			select {
+			case msg := <-msgCh:
+				if !yield(msg) {
+					sub.Unsubscribe()
+					return
+				}
+			case <-sub.UnsubChan:
+				sub.Unsubscribe()
+				return
+			}
+		}
+	}
+
+	return iterFun, sub
+}
+
+func (bb *Broadcaster[TData]) unsubscribe(p *broadcastSubscription[TData]) {
+	bb.masterLock.Lock()
+	defer bb.masterLock.Unlock()
+
+	p.subLock.Lock()
+	defer p.subLock.Unlock()
+
+	if p.Chan != nil {
+		close(p.Chan)
+		p.Chan = nil
+	}
+	if p.UnsubChan != nil {
+		syncext.WriteNonBlocking(p.UnsubChan, true)
+		close(p.UnsubChan)
+		p.UnsubChan = nil
+	}
+
+	bb.subscriptions = langext.ArrFilter(bb.subscriptions, func(v *broadcastSubscription[TData]) bool {
+		return v.ID != p.ID
+	})
+}

dataext/broadcaster_test.go

@@ -0,0 +1,332 @@
+package dataext
+
+import (
+	"context"
+	"sync"
+	"testing"
+	"time"
+)
+
+func TestNewBroadcast(t *testing.T) {
+	bb := NewBroadcast[string](10)
+	if bb == nil {
+		t.Fatal("NewBroadcast returned nil")
+	}
+	if bb.masterLock == nil {
+		t.Fatal("masterLock is nil")
+	}
+	if bb.subscriptions == nil {
+		t.Fatal("subscriptions is nil")
+	}
+}
+
+func TestBroadcast_SubscribeByCallback(t *testing.T) {
+	bb := NewBroadcast[string](10)
+
+	var received string
+	var wg sync.WaitGroup
+	wg.Add(1)
+
+	callback := func(msg string) {
+		received = msg
+		wg.Done()
+	}
+
+	sub := bb.SubscribeByCallback(callback)
+	defer sub.Unsubscribe()
+
+	// Publish a message
+	subs, receivers := bb.Publish("hello")
+
+	if subs != 1 {
+		t.Fatalf("Expected 1 subscriber, got %d", subs)
+	}
+
+	if receivers != 1 {
+		t.Fatalf("Expected 1 receiver, got %d", receivers)
+	}
+
+	// Wait for the callback to be executed
+	wg.Wait()
+
+	if received != "hello" {
+		t.Fatalf("Expected to receive 'hello', got '%s'", received)
+	}
+}
+
+func TestBroadcast_SubscribeByChan(t *testing.T) {
+	bb := NewBroadcast[string](10)
+
+	ch, sub := bb.SubscribeByChan(1)
+	defer sub.Unsubscribe()
+
+	// Publish a message
+	subs, receivers := bb.Publish("hello")
+
+	if subs != 1 {
+		t.Fatalf("Expected 1 subscriber, got %d", subs)
+	}
+
+	if receivers != 1 {
+		t.Fatalf("Expected 1 receiver, got %d", receivers)
+	}
+
+	// Read from the channel with a timeout to avoid blocking
+	select {
+	case msg := <-ch:
+		if msg != "hello" {
+			t.Fatalf("Expected to receive 'hello', got '%s'", msg)
+		}
+	case <-time.After(time.Second):
+		t.Fatal("Timed out waiting for message")
+	}
+}
+
+func TestBroadcast_SubscribeByIter(t *testing.T) {
+	bb := NewBroadcast[string](10)
+
+	iterSeq, sub := bb.SubscribeByIter(1)
+	defer sub.Unsubscribe()
+
+	// Channel to communicate when message is received
+	done := make(chan bool)
+	received := false
+
+	// Start a goroutine to use the iterator
+	go func() {
+		for msg := range iterSeq {
+			if msg == "hello" {
+				received = true
+				done <- true
+				return // Stop iteration
+			}
+		}
+	}()
+
+	// Give time for the iterator to start
+	time.Sleep(100 * time.Millisecond)
+
+	// Publish a message
+	bb.Publish("hello")
+
+	// Wait for the message to be received or timeout
+	select {
+	case <-done:
+		if !received {
+			t.Fatal("Message was received but not 'hello'")
+		}
+	case <-time.After(time.Second):
+		t.Fatal("Timed out waiting for message")
+	}
+
+	subCount := bb.SubscriberCount()
+	if subCount != 0 {
+		t.Fatalf("Expected 0 receivers, got %d", subCount)
+	}
+}
+
+func TestBroadcast_Publish(t *testing.T) {
+	bb := NewBroadcast[string](10)
+
+	// Test publishing with no subscribers
+	subs, receivers := bb.Publish("hello")
+	if subs != 0 {
+		t.Fatalf("Expected 0 subscribers, got %d", subs)
+	}
+	if receivers != 0 {
+		t.Fatalf("Expected 0 receivers, got %d", receivers)
+	}
+
+	// Add a subscriber
+	ch, sub := bb.SubscribeByChan(1)
+	defer sub.Unsubscribe()
+
+	// Publish a message
+	subs, receivers = bb.Publish("hello")
+	if subs != 1 {
+		t.Fatalf("Expected 1 subscriber, got %d", subs)
+	}
+	if receivers != 1 {
+		t.Fatalf("Expected 1 receiver, got %d", receivers)
+	}
+
+	// Verify the message was received
+	select {
+	case msg := <-ch:
+		if msg != "hello" {
+			t.Fatalf("Expected to receive 'hello', got '%s'", msg)
+		}
+	case <-time.After(time.Second):
+		t.Fatal("Timed out waiting for message")
+	}
+
+	// Test non-blocking behavior with a full channel
+	// First fill the channel
+	bb.Publish("fill")
+
+	// Now publish again - this should not block but may skip the receiver
+	subs, receivers = bb.Publish("overflow")
+	if subs != 1 {
+		t.Fatalf("Expected 1 subscriber, got %d", subs)
+	}
+	_ = receivers // may be 0 if channel is full
+
+	// Drain the channel
+	<-ch
+}
+
+func TestBroadcast_PublishWithTimeout(t *testing.T) {
+	bb := NewBroadcast[string](10)
+
+	// Add a subscriber with a channel
+	ch, sub := bb.SubscribeByChan(1)
+	defer sub.Unsubscribe()
+
+	// Publish with a timeout
+	subs, receivers := bb.PublishWithTimeout("hello", 100*time.Millisecond)
+	if subs != 1 {
+		t.Fatalf("Expected 1 subscriber, got %d", subs)
+	}
+	if receivers != 1 {
+		t.Fatalf("Expected 1 receiver, got %d", receivers)
+	}
+
+	// Verify the message was received
+	select {
+	case msg := <-ch:
+		if msg != "hello" {
+			t.Fatalf("Expected to receive 'hello', got '%s'", msg)
+		}
+	case <-time.After(time.Second):
+		t.Fatal("Timed out waiting for message")
+	}
+
+	// Fill the channel
+	bb.Publish("fill")
+
+	// Test timeout behavior with a full channel
+	start := time.Now()
+	subs, receivers = bb.PublishWithTimeout("timeout-test", 50*time.Millisecond)
+	elapsed := time.Since(start)
+
+	if subs != 1 {
+		t.Fatalf("Expected 1 subscriber, got %d", subs)
+	}
+
+	// The receiver count should be 0 if the timeout occurred
+	if elapsed < 50*time.Millisecond {
+		t.Fatalf("Expected to wait at least 50ms, only waited %v", elapsed)
+	}
+
+	// Drain the channel
+	<-ch
+}
+
+func TestBroadcast_PublishWithContext(t *testing.T) {
+	bb := NewBroadcast[string](10)
+
+	// Add a subscriber with a channel
+	ch, sub := bb.SubscribeByChan(1)
+	defer sub.Unsubscribe()
+
+	// Create a context
+	ctx, cancel := context.WithTimeout(context.Background(), 100*time.Millisecond)
+	defer cancel()
+
+	// Publish with context
+	subs, receivers, err := bb.PublishWithContext(ctx, "hello")
+	if err != nil {
+		t.Fatalf("Unexpected error: %v", err)
+	}
+	if subs != 1 {
+		t.Fatalf("Expected 1 subscriber, got %d", subs)
+	}
+	if receivers != 1 {
+		t.Fatalf("Expected 1 receiver, got %d", receivers)
+	}
+
+	// Verify the message was received
+	select {
+	case msg := <-ch:
+		if msg != "hello" {
+			t.Fatalf("Expected to receive 'hello', got '%s'", msg)
+		}
+	case <-time.After(time.Second):
+		t.Fatal("Timed out waiting for message")
+	}
+
+	// Fill the channel
+	bb.Publish("fill")
+
+	// Test context cancellation with a full channel
+	ctx, cancel = context.WithCancel(context.Background())
+
+	// Cancel the context after a short delay
+	go func() {
+		time.Sleep(50 * time.Millisecond)
+		cancel()
+	}()
+
+	start := time.Now()
+	subs, receivers, err = bb.PublishWithContext(ctx, "context-test")
+	elapsed := time.Since(start)
+
+	if subs != 1 {
+		t.Fatalf("Expected 1 subscriber, got %d", subs)
+	}
+
+	// Should get a context canceled error
+	if err == nil {
+		t.Fatal("Expected context canceled error, got nil")
+	}
+
+	if elapsed < 50*time.Millisecond {
+		t.Fatalf("Expected to wait at least 50ms, only waited %v", elapsed)
+	}
+
+	// Drain the channel
+	<-ch
+}
+
+func TestBroadcast_Unsubscribe(t *testing.T) {
+	bb := NewBroadcast[string](10)
+
+	// Add a subscriber
+	ch, sub := bb.SubscribeByChan(1)
+
+	// Publish a message
+	subs, receivers := bb.Publish("hello")
+	if subs != 1 {
+		t.Fatalf("Expected 1 subscriber, got %d", subs)
+	}
+	if receivers != 1 {
+		t.Fatalf("Expected 1 receiver, got %d", receivers)
+	}
+
+	// Verify the message was received
+	select {
+	case msg := <-ch:
+		if msg != "hello" {
+			t.Fatalf("Expected to receive 'hello', got '%s'", msg)
+		}
+	case <-time.After(time.Second):
+		t.Fatal("Timed out waiting for message")
+	}
+
+	// Unsubscribe
+	sub.Unsubscribe()
+
+	// Publish again
+	subs, receivers = bb.Publish("after-unsub")
+	if subs != 0 {
+		t.Fatalf("Expected 0 subscribers after unsubscribe, got %d", subs)
+	}
+	if receivers != 0 {
+		t.Fatalf("Expected 0 receivers after unsubscribe, got %d", receivers)
+	}
+
+	// Check that the subscriber count is 0
+	if bb.SubscriberCount() != 0 {
+		t.Fatalf("Expected SubscriberCount() == 0, got %d", bb.SubscriberCount())
+	}
+}