@multiplayer-app/otlp-core/src/MultiplayerIdGenerator.ts

Multiplayer otlp core

import {
  RandomIdGenerator,
  SamplingDecision,
} from '@opentelemetry/sdk-trace-base'
import { DebugSessionType } from './type'
import { MultiplayerTraceIdRatioBasedSampler } from './MultiplayerTraceIdRatioBasedSampler'
import {
  MULTIPLAYER_TRACE_DEBUG_PREFIX,
  MULTIPLAYER_TRACE_DOC_PREFIX,
  MULTIPLAYER_TRACE_CONTINUOUS_DEBUG_PREFIX,
} from './constants.base'

const SHARED_CHAR_CODES_ARRAY = Array(32)
function getIdGenerator(bytes: number): () => string {
  return function generateId() {
    for (let i = 0; i < bytes * 2; i++) {
      SHARED_CHAR_CODES_ARRAY[i] = Math.floor(Math.random() * 16) + 48
      // valid hex characters in the range 48-57 and 97-102
      if (SHARED_CHAR_CODES_ARRAY[i] >= 58) {
        SHARED_CHAR_CODES_ARRAY[i] += 39
      }
    }
    return String.fromCharCode.apply(
      null,
      SHARED_CHAR_CODES_ARRAY.slice(0, bytes * 2),
    )
  }
}

export class MultiplayerIdGenerator extends RandomIdGenerator {
  debugSessionShortId: string
  debugSessionType: DebugSessionType
  docSpanSampler: MultiplayerTraceIdRatioBasedSampler

  generateLongId: () => string

  constructor({ autoDocTracesRatio = 0 }: { autoDocTracesRatio: number }) {
    super()

    this.docSpanSampler = new MultiplayerTraceIdRatioBasedSampler(autoDocTracesRatio)

    this.generateLongId = getIdGenerator(16)
    this.debugSessionShortId = ''
    this.debugSessionType = DebugSessionType.PLAIN

    this.generateTraceId = () => {
      const traceId = this.generateLongId()

      if (this.debugSessionShortId) {
        let debugSessionTypePrefix: string = ''
        switch (this.debugSessionType) {
          case DebugSessionType.CONTINUOUS:
            debugSessionTypePrefix = MULTIPLAYER_TRACE_CONTINUOUS_DEBUG_PREFIX
            break
          default:
            debugSessionTypePrefix = MULTIPLAYER_TRACE_DEBUG_PREFIX
        }

        const prefix = `${debugSessionTypePrefix}${this.debugSessionShortId}`

        const debugSessionTraceId = `${prefix}${traceId.substring(prefix.length, traceId.length)}`

        return debugSessionTraceId
      } else if (this._isDocTrace(traceId)) {
        return `${MULTIPLAYER_TRACE_DOC_PREFIX}${traceId.slice(MULTIPLAYER_TRACE_DOC_PREFIX.length, traceId.length)}`
      }

      return traceId
    }
  }

  setSessionId(
    debugSessionShortId: string,
    debugSessionType: DebugSessionType = DebugSessionType.PLAIN,
  ) {
    this.debugSessionShortId = debugSessionShortId
    this.debugSessionType = debugSessionType
  }

  _isDocTrace(traceId: string) {
    return this.docSpanSampler.shouldSample(
      undefined,
      traceId,
    ).decision === SamplingDecision.RECORD_AND_SAMPLED
  }
}