issue #106: work in progress

example_user_rate_limit_test.go

@@ -0,0 +1,52 @@
+package semaphore_test
+
+import (
+	"context"
+	"sync"
+
+	"github.com/kamilsk/semaphore"
+)
+
+type User int
+
+type Config struct {
+	DefaultUser     User
+	DefaultCapacity int
+}
+
+func Example_userRateLimitation() {
+	var (
+		mx       sync.RWMutex
+		capacity map[User]int                 = make(map[User]int)
+		limiters map[User]semaphore.Semaphore = make(map[User]semaphore.Semaphore)
+
+		config Config = Config{
+			DefaultUser:     0,
+			DefaultCapacity: 10,
+		}
+	)
+
+	_ = func(ctx context.Context) semaphore.Semaphore {
+		user, ok := ctx.Value("user").(User)
+		if !ok {
+			user = config.DefaultUser
+		}
+
+		mx.RLock()
+		sem, ok := limiters[user]
+		mx.RUnlock()
+
+		if !ok {
+			c, ok := capacity[user]
+			if !ok {
+				c = config.DefaultCapacity
+			}
+			sem = semaphore.New(c)
+
+			mx.Lock()
+			limiters[user] = sem
+			mx.Unlock()
+		}
+		return sem
+	}
+}