Moved to google.golang.org/genproto/googleapis/api/annotations

Fixes #52

vendor/github.com/go-kit/kit/ratelimit/token_bucket.go

@@ -0,0 +1,42 @@
+package ratelimit
+
+import (
+	"context"
+	"errors"
+	"time"
+
+	"github.com/juju/ratelimit"
+
+	"github.com/go-kit/kit/endpoint"
+)
+
+// ErrLimited is returned in the request path when the rate limiter is
+// triggered and the request is rejected.
+var ErrLimited = errors.New("rate limit exceeded")
+
+// NewTokenBucketLimiter returns an endpoint.Middleware that acts as a rate
+// limiter based on a token-bucket algorithm. Requests that would exceed the
+// maximum request rate are simply rejected with an error.
+func NewTokenBucketLimiter(tb *ratelimit.Bucket) endpoint.Middleware {
+	return func(next endpoint.Endpoint) endpoint.Endpoint {
+		return func(ctx context.Context, request interface{}) (interface{}, error) {
+			if tb.TakeAvailable(1) == 0 {
+				return nil, ErrLimited
+			}
+			return next(ctx, request)
+		}
+	}
+}
+
+// NewTokenBucketThrottler returns an endpoint.Middleware that acts as a
+// request throttler based on a token-bucket algorithm. Requests that would
+// exceed the maximum request rate are delayed via the parameterized sleep
+// function. By default you may pass time.Sleep.
+func NewTokenBucketThrottler(tb *ratelimit.Bucket, sleep func(time.Duration)) endpoint.Middleware {
+	return func(next endpoint.Endpoint) endpoint.Endpoint {
+		return func(ctx context.Context, request interface{}) (interface{}, error) {
+			sleep(tb.Take(1))
+			return next(ctx, request)
+		}
+	}
+}