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Girish Gowdra631ef3d2020-06-15 10:45:52 -07001// Copyright (c) 2017 Uber Technologies, Inc.
2//
3// Licensed under the Apache License, Version 2.0 (the "License");
4// you may not use this file except in compliance with the License.
5// You may obtain a copy of the License at
6//
7// http://www.apache.org/licenses/LICENSE-2.0
8//
9// Unless required by applicable law or agreed to in writing, software
10// distributed under the License is distributed on an "AS IS" BASIS,
11// WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
12// See the License for the specific language governing permissions and
13// limitations under the License.
14
15package rpcmetrics
16
17import "sync"
18
19// normalizedEndpoints is a cache for endpointName -> safeName mappings.
20type normalizedEndpoints struct {
21 names map[string]string
22 maxSize int
23 defaultName string
24 normalizer NameNormalizer
25 mux sync.RWMutex
26}
27
28func newNormalizedEndpoints(maxSize int, normalizer NameNormalizer) *normalizedEndpoints {
29 return &normalizedEndpoints{
30 maxSize: maxSize,
31 normalizer: normalizer,
32 names: make(map[string]string, maxSize),
33 }
34}
35
36// normalize looks up the name in the cache, if not found it uses normalizer
37// to convert the name to a safe name. If called with more than maxSize unique
38// names it returns "" for all other names beyond those already cached.
39func (n *normalizedEndpoints) normalize(name string) string {
40 n.mux.RLock()
41 norm, ok := n.names[name]
42 l := len(n.names)
43 n.mux.RUnlock()
44 if ok {
45 return norm
46 }
47 if l >= n.maxSize {
48 return ""
49 }
50 return n.normalizeWithLock(name)
51}
52
53func (n *normalizedEndpoints) normalizeWithLock(name string) string {
54 norm := n.normalizer.Normalize(name)
55 n.mux.Lock()
56 defer n.mux.Unlock()
57 // cache may have grown while we were not holding the lock
58 if len(n.names) >= n.maxSize {
59 return ""
60 }
61 n.names[name] = norm
62 return norm
63}