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
|
// Copyright 2017, OpenCensus 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
// limitations under the License.
//
package stats
import (
"sync"
"sync/atomic"
)
// Measure represents a type of metric to be tracked and recorded.
// For example, latency, request Mb/s, and response Mb/s are measures
// to collect from a server.
//
// Each measure needs to be registered before being used.
// Measure constructors such as Int64 and
// Float64 automatically registers the measure
// by the given name.
// Each registered measure needs to be unique by name.
// Measures also have a description and a unit.
type Measure interface {
Name() string
Description() string
Unit() string
}
// measureDescriptor is the untyped descriptor associated with each measure.
// Int64Measure and Float64Measure wrap measureDescriptor to provide typed
// recording APIs.
// Two Measures with the same name will have the same measureDescriptor.
type measureDescriptor struct {
subs int32 // access atomically
name string
description string
unit string
}
func (m *measureDescriptor) subscribe() {
atomic.StoreInt32(&m.subs, 1)
}
func (m *measureDescriptor) subscribed() bool {
return atomic.LoadInt32(&m.subs) == 1
}
var (
mu sync.RWMutex
measures = make(map[string]*measureDescriptor)
)
func registerMeasureHandle(name, desc, unit string) *measureDescriptor {
mu.Lock()
defer mu.Unlock()
if stored, ok := measures[name]; ok {
return stored
}
m := &measureDescriptor{
name: name,
description: desc,
unit: unit,
}
measures[name] = m
return m
}
// Measurement is the numeric value measured when recording stats. Each measure
// provides methods to create measurements of their kind. For example, Int64Measure
// provides M to convert an int64 into a measurement.
type Measurement struct {
v float64
m Measure
}
// Value returns the value of the Measurement as a float64.
func (m Measurement) Value() float64 {
return m.v
}
// Measure returns the Measure from which this Measurement was created.
func (m Measurement) Measure() Measure {
return m.m
}
|
