64 lines
1.8 KiB
Go
64 lines
1.8 KiB
Go
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// Copyright (c) 2017 Uber Technologies, Inc.
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//
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// Licensed under the Apache License, Version 2.0 (the "License");
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// you may not use this file except in compliance with the License.
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// You may obtain a copy of the License at
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//
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// http://www.apache.org/licenses/LICENSE-2.0
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//
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// Unless required by applicable law or agreed to in writing, software
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// distributed under the License is distributed on an "AS IS" BASIS,
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// WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
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// See the License for the specific language governing permissions and
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// limitations under the License.
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package rpcmetrics
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import "sync"
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// normalizedEndpoints is a cache for endpointName -> safeName mappings.
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type normalizedEndpoints struct {
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names map[string]string
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maxSize int
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defaultName string
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normalizer NameNormalizer
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mux sync.RWMutex
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}
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func newNormalizedEndpoints(maxSize int, normalizer NameNormalizer) *normalizedEndpoints {
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return &normalizedEndpoints{
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maxSize: maxSize,
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normalizer: normalizer,
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names: make(map[string]string, maxSize),
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}
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}
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// normalize looks up the name in the cache, if not found it uses normalizer
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// to convert the name to a safe name. If called with more than maxSize unique
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// names it returns "" for all other names beyond those already cached.
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func (n *normalizedEndpoints) normalize(name string) string {
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n.mux.RLock()
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norm, ok := n.names[name]
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l := len(n.names)
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n.mux.RUnlock()
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if ok {
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return norm
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}
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if l >= n.maxSize {
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return ""
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}
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return n.normalizeWithLock(name)
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}
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func (n *normalizedEndpoints) normalizeWithLock(name string) string {
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norm := n.normalizer.Normalize(name)
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n.mux.Lock()
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defer n.mux.Unlock()
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// cache may have grown while we were not holding the lock
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if len(n.names) >= n.maxSize {
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return ""
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}
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n.names[name] = norm
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return norm
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}
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