snapshot of https://github.com/ThreeDotsLabs/watermill.git (master, 2026-09-15; blobs > 131072B omitted)

message/router/middleware/throttle.go

@@ -0,0 +1,31 @@
+package middleware
+
+import (
+	"time"
+
+	"github.com/ThreeDotsLabs/watermill/message"
+)
+
+// Throttle provides a middleware that limits the amount of messages processed per unit of time.
+// This may be done e.g. to prevent excessive load caused by running a handler on a long queue of unprocessed messages.
+type Throttle struct {
+	ticker *time.Ticker
+}
+
+// NewThrottle creates a new Throttle middleware.
+// Example duration and count: NewThrottle(10, time.Second) for 10 messages per second
+func NewThrottle(count int64, duration time.Duration) *Throttle {
+	return &Throttle{
+		ticker: time.NewTicker(duration / time.Duration(count)),
+	}
+}
+
+// Middleware returns the Throttle middleware.
+func (t Throttle) Middleware(h message.HandlerFunc) message.HandlerFunc {
+	return func(message *message.Message) ([]*message.Message, error) {
+		// throttle is shared by multiple handlers, which will wait for their "tick"
+		<-t.ticker.C
+
+		return h(message)
+	}
+}