/
TraceIdRatioBasedSampler.ts
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/
TraceIdRatioBasedSampler.ts
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/*
* 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 {
Sampler,
SamplingDecision,
SamplingResult,
isValidTraceId,
} from '@opentelemetry/api';
/**
* @deprecated Use the one defined in @opentelemetry/sdk-trace-base instead.
* Sampler that samples a given fraction of traces based of trace id deterministically.
*/
export class TraceIdRatioBasedSampler implements Sampler {
private _upperBound: number;
constructor(private readonly _ratio: number = 0) {
this._ratio = this._normalize(_ratio);
this._upperBound = Math.floor(this._ratio * 0xffffffff);
}
shouldSample(context: unknown, traceId: string): SamplingResult {
return {
decision:
isValidTraceId(traceId) && this._accumulate(traceId) < this._upperBound
? SamplingDecision.RECORD_AND_SAMPLED
: SamplingDecision.NOT_RECORD,
};
}
toString(): string {
return `TraceIdRatioBased{${this._ratio}}`;
}
private _normalize(ratio: number): number {
if (typeof ratio !== 'number' || isNaN(ratio)) return 0;
return ratio >= 1 ? 1 : ratio <= 0 ? 0 : ratio;
}
private _accumulate(traceId: string): number {
let accumulation = 0;
for (let i = 0; i < traceId.length / 8; i++) {
const pos = i * 8;
const part = parseInt(traceId.slice(pos, pos + 8), 16);
accumulation = (accumulation ^ part) >>> 0;
}
return accumulation;
}
}