1
2
3
4
5
6
7
8
9
10
11
12
13
14
15
16
17
18
19
20
21
22
23
24
25
26
27
28
29
30
31
32
33
34
35
36
37
38
39
40
41
42
43
44
45
46
47
48
49
50
51
52
53
54
55
56
57
58
59
60
61
62
63
64
65
66
67
68
69
70
71
72
73
74
75
76
77
78
79
80
81
82
83
84
85
86
87
88
89
90
91
92
93
94
95
96
97
98
99
100
101
102
103
104
105
106
107
108
109
110
111
112
113
114
115
116
117
118
119
120
121
122
123
124
125
126
127
128
129
130
|
// Copyright 2025 The Prometheus 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
package otlptranslator
import "strings"
// UnitNamer is a helper for building compliant unit names.
// It processes OpenTelemetry Protocol (OTLP) unit strings and converts them
// to Prometheus-compliant unit names.
//
// Example usage:
//
// namer := UnitNamer{UTF8Allowed: false}
// result := namer.Build("s") // "seconds"
// result = namer.Build("By/s") // "bytes_per_second"
type UnitNamer struct {
UTF8Allowed bool
}
// Build builds a unit name for the specified unit string.
// It processes the unit by splitting it into main and per components,
// applying unit mappings, and cleaning up invalid characters when UTF8Allowed is false.
//
// Unit mappings include:
// - Time: s→seconds, ms→milliseconds, h→hours
// - Bytes: By→bytes, KBy→kilobytes, MBy→megabytes
// - SI: m→meters, V→volts, W→watts
// - Special: 1→"" (empty), %→percent
//
// Examples:
//
// namer := UnitNamer{UTF8Allowed: false}
// namer.Build("s") // "seconds"
// namer.Build("requests/s") // "requests_per_second"
// namer.Build("1") // "" (dimensionless)
func (un *UnitNamer) Build(unit string) string {
mainUnit, perUnit := buildUnitSuffixes(unit)
if !un.UTF8Allowed {
mainUnit, perUnit = cleanUpUnit(mainUnit), cleanUpUnit(perUnit)
}
var u string
switch {
case mainUnit != "" && perUnit != "":
u = mainUnit + "_" + perUnit
case mainUnit != "":
u = mainUnit
default:
u = perUnit
}
// Clean up leading and trailing underscores
if len(u) > 0 && u[0:1] == "_" {
u = u[1:]
}
if len(u) > 0 && u[len(u)-1:] == "_" {
u = u[:len(u)-1]
}
return u
}
// Retrieve the Prometheus "basic" unit corresponding to the specified "basic" unit.
// Returns the specified unit if not found in unitMap.
func unitMapGetOrDefault(unit string) string {
if promUnit, ok := unitMap[unit]; ok {
return promUnit
}
return unit
}
// Retrieve the Prometheus "per" unit corresponding to the specified "per" unit.
// Returns the specified unit if not found in perUnitMap.
func perUnitMapGetOrDefault(perUnit string) string {
if promPerUnit, ok := perUnitMap[perUnit]; ok {
return promPerUnit
}
return perUnit
}
// buildUnitSuffixes builds the main and per unit suffixes for the specified unit
// but doesn't do any special character transformation to accommodate Prometheus naming conventions.
// Removing trailing underscores or appending suffixes is done in the caller.
func buildUnitSuffixes(unit string) (mainUnitSuffix, perUnitSuffix string) {
// Split unit at the '/' if any
unitTokens := strings.SplitN(unit, "/", 2)
if len(unitTokens) > 0 {
// Main unit
// Update if not blank and doesn't contain '{}'
mainUnitOTel := strings.TrimSpace(unitTokens[0])
if mainUnitOTel != "" && !strings.ContainsAny(mainUnitOTel, "{}") {
mainUnitSuffix = unitMapGetOrDefault(mainUnitOTel)
}
// Per unit
// Update if not blank and doesn't contain '{}'
if len(unitTokens) > 1 && unitTokens[1] != "" {
perUnitOTel := strings.TrimSpace(unitTokens[1])
if perUnitOTel != "" && !strings.ContainsAny(perUnitOTel, "{}") {
perUnitSuffix = perUnitMapGetOrDefault(perUnitOTel)
}
if perUnitSuffix != "" {
perUnitSuffix = "per_" + perUnitSuffix
}
}
}
return mainUnitSuffix, perUnitSuffix
}
// cleanUpUnit cleans up unit so it matches model.LabelNameRE.
func cleanUpUnit(unit string) string {
// Multiple consecutive underscores are replaced with a single underscore.
// This is part of the OTel to Prometheus specification: https://github.com/open-telemetry/opentelemetry-specification/blob/v1.38.0/specification/compatibility/prometheus_and_openmetrics.md#otlp-metric-points-to-prometheus.
return strings.TrimPrefix(multipleUnderscoresRE.ReplaceAllString(
strings.Map(replaceInvalidMetricChar, unit),
"_",
), "_")
}
|
