started responder pool

2026-04-20 06:57:48 -04:00
parent 3066802f62
commit 9859796338
9 changed files with 585 additions and 0 deletions
@@ -0,0 +1,141 @@
+package responderpool
+
+import (
+	"container/list"
+	"context"
+	"errors"
+	"git.wisehodl.dev/jay/go-honeybee/transport"
+	"time"
+)
+
+type onExitFunc func(id string, kind PoolEventKind)
+
+type ReceivedMessage struct {
+	data       []byte
+	receivedAt time.Time
+}
+
+func RunReader(
+	ctx context.Context,
+	id string,
+	conn *transport.Connection,
+	messages chan<- ReceivedMessage,
+	heartbeat chan<- struct{},
+	onPeerClose onExitFunc,
+) {
+	for {
+		select {
+		case <-ctx.Done():
+			return
+		case data, ok := <-conn.Incoming():
+			if !ok {
+				// determine exit kind
+				// by default, the peer dropped unexpectedly
+				kind := EventPeerDropped
+				select {
+				case err := <-conn.Errors():
+					if errors.Is(err, transport.ErrPeerClosedClean) {
+						kind = EventPeerDisconnected
+					}
+				default:
+				}
+
+				onPeerClose(id, kind)
+				return
+			}
+
+			messages <- ReceivedMessage{data: data, receivedAt: time.Now()}
+
+			select {
+			case heartbeat <- struct{}{}:
+			case <-ctx.Done():
+				return
+			}
+		}
+	}
+}
+
+func RunForwarder(
+	ctx context.Context,
+	id string,
+	messages <-chan ReceivedMessage,
+	inbox chan<- InboxMessage,
+	maxQueueSize int,
+) {
+	queue := list.New()
+
+	for {
+		var out chan<- InboxMessage
+		var next ReceivedMessage
+
+		// enable inbox if it is populated
+		if queue.Len() > 0 {
+			out = inbox
+
+			// read the first message in the queue
+			next = queue.Front().Value.(ReceivedMessage)
+		}
+
+		select {
+		case <-ctx.Done():
+			return
+		case msg := <-messages:
+			// limit queue size if maximum is configured
+			if maxQueueSize > 0 && queue.Len() >= maxQueueSize {
+				// drop oldest message
+				queue.Remove(queue.Front())
+			}
+			// add new message
+			queue.PushBack(msg)
+		// send next message to inbox
+		case out <- InboxMessage{
+			ID:         id,
+			Data:       next.data,
+			ReceivedAt: next.receivedAt,
+		}:
+			// drop message from queue
+			queue.Remove(queue.Front())
+		}
+	}
+}
+
+func RunWatchdog(
+	ctx context.Context,
+	id string,
+	timeout time.Duration,
+	heartbeat <-chan struct{},
+	onTimeout onExitFunc,
+) {
+	// disable watchdog timeout if not configured
+	if timeout <= 0 {
+		// wait for cancel and exit
+		select {
+		case <-ctx.Done():
+		}
+		return
+	}
+
+	timer := time.NewTimer(timeout)
+	defer timer.Stop()
+
+	for {
+		select {
+		case <-ctx.Done():
+			return
+		case <-heartbeat:
+			// drain the timer channel and reset
+			if !timer.Stop() {
+				select {
+				case <-timer.C:
+				default:
+				}
+			}
+			timer.Reset(timeout)
+		// timer completed
+		case <-timer.C:
+			// evict inactive peer
+			onTimeout(id, EventPeerEvicted)
+			return
+		}
+	}
+}