@opentelemetry/sdk-trace-base
Version:
39 lines • 1.47 kB
JavaScript
/*
* Copyright The OpenTelemetry Authors
* SPDX-License-Identifier: Apache-2.0
*/
const SPAN_ID_BYTES = 8;
const TRACE_ID_BYTES = 16;
export class RandomIdGenerator {
/**
* Returns a random 16-byte trace ID formatted/encoded as a 32 lowercase hex
* characters corresponding to 128 bits.
*/
generateTraceId = getIdGenerator(TRACE_ID_BYTES);
/**
* Returns a random 8-byte span ID formatted/encoded as a 16 lowercase hex
* characters corresponding to 64 bits.
*/
generateSpanId = getIdGenerator(SPAN_ID_BYTES);
}
const SHARED_BUFFER = Buffer.allocUnsafe(TRACE_ID_BYTES);
function getIdGenerator(bytes) {
return function generateId() {
for (let i = 0; i < bytes / 4; i++) {
// unsigned right shift drops decimal part of the number
// it is required because if a number between 2**32 and 2**32 - 1 is generated, an out of range error is thrown by writeUInt32BE
SHARED_BUFFER.writeUInt32BE((Math.random() * 2 ** 32) >>> 0, i * 4);
}
// If buffer is all 0, set the last byte to 1 to guarantee a valid w3c id is generated
for (let i = 0; i < bytes; i++) {
if (SHARED_BUFFER[i] > 0) {
break;
}
else if (i === bytes - 1) {
SHARED_BUFFER[bytes - 1] = 1;
}
}
return SHARED_BUFFER.toString('hex', 0, bytes);
};
}
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