/
Histogram.ts
79 lines (72 loc) · 2.37 KB
/
Histogram.ts
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
/*
* Copyright The OpenTelemetry 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
*
* https://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.
*/
import {
HistogramAggregatorType,
Point,
Histogram,
AggregatorKind,
} from '../types';
import { HrTime } from '@opentelemetry/api';
import { hrTime } from '@opentelemetry/core';
/**
* Basic aggregator which observes events and counts them in pre-defined buckets
* and provides the total sum and count of all observations.
*/
export class HistogramAggregator implements HistogramAggregatorType {
public kind: AggregatorKind.HISTOGRAM = AggregatorKind.HISTOGRAM;
private _current: Histogram;
private _lastUpdateTime: HrTime;
private readonly _boundaries: number[];
constructor(boundaries: number[]) {
if (boundaries === undefined || boundaries.length === 0) {
throw new Error('HistogramAggregator should be created with boundaries.');
}
// we need to an ordered set to be able to correctly compute count for each
// boundary since we'll iterate on each in order.
this._boundaries = boundaries.sort((a, b) => a - b);
this._current = this._newEmptyCheckpoint();
this._lastUpdateTime = hrTime();
}
update(value: number): void {
this._lastUpdateTime = hrTime();
this._current.count += 1;
this._current.sum += value;
for (let i = 0; i < this._boundaries.length; i++) {
if (value < this._boundaries[i]) {
this._current.buckets.counts[i] += 1;
return;
}
}
// value is above all observed boundaries
this._current.buckets.counts[this._boundaries.length] += 1;
}
toPoint(): Point<Histogram> {
return {
value: this._current,
timestamp: this._lastUpdateTime,
};
}
private _newEmptyCheckpoint(): Histogram {
return {
buckets: {
boundaries: this._boundaries,
counts: this._boundaries.map(() => 0).concat([0]),
},
sum: 0,
count: 0,
};
}
}