108 lines
3 KiB
Go
108 lines
3 KiB
Go
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// 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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// NameNormalizer is used to convert the endpoint names to strings
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// that can be safely used as tags in the metrics.
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type NameNormalizer interface {
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Normalize(name string) string
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}
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// DefaultNameNormalizer converts endpoint names so that they contain only characters
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// from the safe charset [a-zA-Z0-9-./_]. All other characters are replaced with '-'.
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var DefaultNameNormalizer = &SimpleNameNormalizer{
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SafeSets: []SafeCharacterSet{
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&Range{From: 'a', To: 'z'},
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&Range{From: 'A', To: 'Z'},
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&Range{From: '0', To: '9'},
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&Char{'-'},
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&Char{'_'},
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&Char{'/'},
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&Char{'.'},
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},
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Replacement: '-',
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}
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// SimpleNameNormalizer uses a set of safe character sets.
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type SimpleNameNormalizer struct {
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SafeSets []SafeCharacterSet
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Replacement byte
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}
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// SafeCharacterSet determines if the given character is "safe"
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type SafeCharacterSet interface {
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IsSafe(c byte) bool
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}
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// Range implements SafeCharacterSet
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type Range struct {
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From, To byte
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}
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// IsSafe implements SafeCharacterSet
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func (r *Range) IsSafe(c byte) bool {
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return c >= r.From && c <= r.To
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}
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// Char implements SafeCharacterSet
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type Char struct {
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Val byte
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}
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// IsSafe implements SafeCharacterSet
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func (ch *Char) IsSafe(c byte) bool {
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return c == ch.Val
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}
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// Normalize checks each character in the string against SafeSets,
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// and if it's not safe substitutes it with Replacement.
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func (n *SimpleNameNormalizer) Normalize(name string) string {
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var retMe []byte
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nameBytes := []byte(name)
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for i, b := range nameBytes {
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if n.safeByte(b) {
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if retMe != nil {
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retMe[i] = b
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}
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} else {
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if retMe == nil {
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retMe = make([]byte, len(nameBytes))
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copy(retMe[0:i], nameBytes[0:i])
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}
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retMe[i] = n.Replacement
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}
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}
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if retMe == nil {
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return name
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}
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return string(retMe)
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}
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// safeByte checks if b against all safe charsets.
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func (n *SimpleNameNormalizer) safeByte(b byte) bool {
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for i := range n.SafeSets {
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if n.SafeSets[i].IsSafe(b) {
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return true
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}
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}
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return false
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}
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