69 lines
2.3 KiB
Go
69 lines
2.3 KiB
Go
// Copyright (c) 2017 Uber Technologies, Inc.
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//
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// Permission is hereby granted, free of charge, to any person obtaining a copy
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// of this software and associated documentation files (the "Software"), to deal
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// in the Software without restriction, including without limitation the rights
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// to use, copy, modify, merge, publish, distribute, sublicense, and/or sell
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// copies of the Software, and to permit persons to whom the Software is
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// furnished to do so, subject to the following conditions:
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//
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// The above copyright notice and this permission notice shall be included in
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// all copies or substantial portions of the Software.
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//
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// THE SOFTWARE IS PROVIDED "AS IS", WITHOUT WARRANTY OF ANY KIND, EXPRESS OR
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// IMPLIED, INCLUDING BUT NOT LIMITED TO THE WARRANTIES OF MERCHANTABILITY,
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// FITNESS FOR A PARTICULAR PURPOSE AND NONINFRINGEMENT. IN NO EVENT SHALL THE
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// AUTHORS OR COPYRIGHT HOLDERS BE LIABLE FOR ANY CLAIM, DAMAGES OR OTHER
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// LIABILITY, WHETHER IN AN ACTION OF CONTRACT, TORT OR OTHERWISE, ARISING FROM,
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// OUT OF OR IN CONNECTION WITH THE SOFTWARE OR THE USE OR OTHER DEALINGS IN
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// THE SOFTWARE.
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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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