pkg/ratelimit: refactor for BBR (tikv#7239)

ref tikv#7167

Signed-off-by: Cabinfever_B <[email protected]>

Co-authored-by: ti-chi-bot[bot] <108142056+ti-chi-bot[bot]@users.noreply.github.com>

pkg/ratelimit/controller.go

@@ -0,0 +1,79 @@
+// Copyright 2023 TiKV Project Authors.
+//
+// Licensed under the Apache License, Version 2.0 (the "License");
+// you may not use this file except in compliance with the License.
+// You may obtain a copy of the License at
+//
+//     http://www.apache.org/licenses/LICENSE-2.0
+//
+// Unless required by applicable law or agreed to in writing, software
+// distributed under the License is distributed on an "AS IS" BASIS,
+// WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
+// See the License for the specific language governing permissions and
+// limitations under the License.
+
+package ratelimit
+
+import (
+	"sync"
+
+	"golang.org/x/time/rate"
+)
+
+var emptyFunc = func() {}
+
+// Controller is a controller which holds multiple limiters to manage the request rate of different objects.
+type Controller struct {
+	limiters sync.Map
+	// the label which is in labelAllowList won't be limited, and only inited by hard code.
+	labelAllowList map[string]struct{}
+}
+
+// NewController returns a global limiter which can be updated in the later.
+func NewController() *Controller {
+	return &Controller{
+		labelAllowList: make(map[string]struct{}),
+	}
+}
+
+// Allow is used to check whether it has enough token.
+func (l *Controller) Allow(label string) (DoneFunc, error) {
+	var ok bool
+	lim, ok := l.limiters.Load(label)
+	if ok {
+		return lim.(*limiter).allow()
+	}
+	return emptyFunc, nil
+}
+
+// Update is used to update Ratelimiter with Options
+func (l *Controller) Update(label string, opts ...Option) UpdateStatus {
+	var status UpdateStatus
+	for _, opt := range opts {
+		status |= opt(label, l)
+	}
+	return status
+}
+
+// GetQPSLimiterStatus returns the status of a given label's QPS limiter.
+func (l *Controller) GetQPSLimiterStatus(label string) (limit rate.Limit, burst int) {
+	if limit, exist := l.limiters.Load(label); exist {
+		return limit.(*limiter).getQPSLimiterStatus()
+	}
+	return 0, 0
+}
+
+// GetConcurrencyLimiterStatus returns the status of a given label's concurrency limiter.
+func (l *Controller) GetConcurrencyLimiterStatus(label string) (limit uint64, current uint64) {
+	if limit, exist := l.limiters.Load(label); exist {
+		return limit.(*limiter).getConcurrencyLimiterStatus()
+	}
+	return 0, 0
+}
+
+// IsInAllowList returns whether this label is in allow list.
+// If returns true, the given label won't be limited
+func (l *Controller) IsInAllowList(label string) bool {
+	_, allow := l.labelAllowList[label]
+	return allow
+}