Function captureMemoryDiagnostics

src/utils/heapDumpService.ts:88–212

(
  trigger: 'manual' | 'auto-1.5GB',
  dumpNumber = 0,
)

 * This helps identify if the leak is in V8 heap (captured) or native memory (not captured).
 */
export async function captureMemoryDiagnostics(
  trigger: 'manual' | 'auto-1.5GB',
  dumpNumber = 0,
): Promise<MemoryDiagnostics> {
  const usage = process.memoryUsage()
  const heapStats = getHeapStatistics()
  const resourceUsage = process.resourceUsage()
  const uptimeSeconds = process.uptime()

  // getHeapSpaceStatistics() is not available in Bun
  let heapSpaceStats: HeapSpaceInfo[] | undefined
  try {
    heapSpaceStats = getHeapSpaceStatistics()
  } catch {
    // Not available in Bun runtime
  }

  // Get active handles/requests count (these are internal APIs but stable)
  const activeHandles = (
    process as unknown as { _getActiveHandles: () => unknown[] }
  )._getActiveHandles().length
  const activeRequests = (
    process as unknown as { _getActiveRequests: () => unknown[] }
  )._getActiveRequests().length

  // Try to count open file descriptors (Linux/macOS)
  let openFileDescriptors: number | undefined
  try {
    openFileDescriptors = (await readdir('/proc/self/fd')).length
  } catch {
    // Not on Linux - try macOS approach would require lsof, skip for now
  }

  // Try to read Linux smaps_rollup for detailed memory breakdown
  let smapsRollup: string | undefined
  try {
    smapsRollup = await readFile('/proc/self/smaps_rollup', 'utf8')
  } catch {
    // Not on Linux or no access - this is fine
  }

  // Calculate native memory (RSS - heap) and growth rate
  const nativeMemory = usage.rss - usage.heapUsed
  const bytesPerSecond = uptimeSeconds > 0 ? usage.rss / uptimeSeconds : 0
  const mbPerHour = (bytesPerSecond * 3600) / (1024 * 1024)

  // Identify potential leaks
  const potentialLeaks: string[] = []
  if (heapStats.number_of_detached_contexts > 0) {
    potentialLeaks.push(
      `${heapStats.number_of_detached_contexts} detached context(s) - possible iframe/context leak`,
    )
  }
  if (activeHandles > 100) {
    potentialLeaks.push(
      `${activeHandles} active handles - possible timer/socket leak`,
    )
  }