pearcord-platform/poll-db-read-budget.js

'use strict'

const DEFAULT_BUDGET_PER_SEC = Math.max(
  5,
  Number(process.env.PEARCORD_POLL_DB_READ_BUDGET_PER_SEC) || 120
)
const WINDOW_MS = 1000

function createPollDbReadBudget (budgetPerSec = DEFAULT_BUDGET_PER_SEC) {
  let windowStart = Date.now()
  let count = 0
  let warned = 0
  let lastWarnAt = 0

  return {
    record (n = 1, { log } = {}) {
      const now = Date.now()
      if (now - windowStart >= WINDOW_MS) {
        windowStart = now
        count = 0
      }
      count += Math.max(0, Number(n) || 0)
      if (count > budgetPerSec && now - lastWarnAt > WINDOW_MS) {
        warned += 1
        lastWarnAt = now
        log?.warn?.('poll-path db read budget exceeded', {
          count,
          budgetPerSec,
          windowMs: WINDOW_MS
        })
      }
      return { count, budgetPerSec, exceeded: count > budgetPerSec }
    },
    stats () {
      return { count, budgetPerSec, warned, windowStart }
    }
  }
}

module.exports = { createPollDbReadBudget, DEFAULT_BUDGET_PER_SEC }